diff --git a/docs/whitedoc/validation.rst b/docs/whitedoc/validation.rst
index 8f13becc1..5226d13d6 100644
--- a/docs/whitedoc/validation.rst
+++ b/docs/whitedoc/validation.rst
@@ -26,20 +26,18 @@ considers to be the current head of the blockchain.
 The validator is written as a collection of workers: local event loops
 communicating with each other via message passing. Workers are spawned
 and killed dynamically, according to connected peers, incoming blocks
-to validate, and active (test)nets.
+to validate, and active (test)chains.
 
-A *net validator* worker is launched by the validator for each *net*
-that it considers alive. A *net* is how we call subset of block chains
-that go through a given root block. This should not be mixed up with
-the *net* in *peer-to-peer network*. Each net validator is responsible
-for handling blocks that belong to this net, and select the best head
-for this net. A main net validator is spawned for the main chain that
+A *chain validator* worker is launched by the validator for each
+*chain* that it considers alive. Each chain validator is responsible for
+handling blocks that belong to this chain, and select the best head for
+this chain. A main chain validator is spawned for the main chain that
 starts at the genesis, a second one when there is an active test
-chain. Forking a net is decided from within the economic protocol.
-In version Alpha, this is only used to try new protocols before self
-amending the main net.
+chain. Forking a chain is decided from within the economic protocol.  In
+version Alpha, this is only used to try new protocols before self
+amending the main chain.
 
-The net validator spawns one *peer validator* worker per connected
+The chain validator spawns one *peer validator* worker per connected
 peer. This set updated, grown or shrinked on the fly, according to the
 connections and deconnection signals from the peer-to-peer component.
 Each peer validator will treat new head proposals from the associated
@@ -78,8 +76,8 @@ everything needed for a block, they will call the *block validator*.
 The *block validator* validates blocks (currently in sequence),
 assuming that all the necessary data have already been retrieved from
 the peer-to-peer network. When a block is valid, it will notify the
-correspondig net validator, that may update its head. In this case,
-the net validator will propagate this information to its associated
+correspondig chain validator, that may update its head. In this case,
+the chain validator will propagate this information to its associated
 *prevalidator*, and may decide to kill or spawn the test network
 according to the protocol's decision.
 
@@ -87,10 +85,10 @@ Prevalidator
 ------------
 .. _prevalidator_component:
 
-To each net validator is associated a *prevalidator* (this may become
+To each chain validator is associated a *prevalidator* (this may become
 an option in the future, to allow running nodes on machines with less
 RAM), that is responsible for the transmission of operations for this
-net over the peer-to-peer network.
+chain over the peer-to-peer network.
 
 To prevent spam, this prevalidator must select the set of operations
 that it considers valid, and the ones that it chooses to broadcast.
diff --git a/src/bin_attacker/attacker_minimal.ml b/src/bin_attacker/attacker_minimal.ml
index 3205a7ccb..cdca9ba6a 100644
--- a/src/bin_attacker/attacker_minimal.ml
+++ b/src/bin_attacker/attacker_minimal.ml
@@ -16,7 +16,7 @@ module Proto = Client_embedded_proto_alpha
 let genesis_block_hashed = Block_hash.of_b58check
     "BLockGenesisGenesisGenesisGenesisGenesisGeneskvg68z"
 let network = Store.Net genesis_block_hashed
-let network = Store.Net_id.Id genesis_block_hashed
+let network = Store.Chain_id.Id genesis_block_hashed
 
 (* the bootstrap accounts and actions like signing to do with them *)
 let source_account = List.nth Proto.Bootstrap_storage.accounts 4
@@ -32,7 +32,7 @@ let block_forged ?prev ops =
     [ MBytes.of_string Proto.Constants_repr.version_number ;
       Proto.Fitness_repr.int64_to_bytes x ] in
   let pred = match prev with None -> genesis_block_hashed | Some x -> x in
-  let block ops = Store.Block_header.{ net_id = network ;
+  let block ops = Store.Block_header.{ chain_id = network ;
                                        predecessor = pred ;
                                        timestamp = Time.now () ;
                                        fitness = from_int64 1L;
@@ -75,7 +75,7 @@ let tx_forged ?dest amount fee =
             fee = of_cents_exn fee ;
             counter = 1l ;
             operations = [tx] ; }) in
-  forge { net_id = network } op
+  forge { chain_id = network } op
 
 (* forge a list of proposals, california eat your heart out *)
 let props_forged period props =
@@ -87,7 +87,7 @@ let props_forged period props =
   let op = Sourced_operations (Delegate_operations {
       source = src.public_key ;
       operations = [props] }) in
-  forge { net_id = network } op
+  forge { chain_id = network } op
 
 (* "forge" a ballot *)
 let ballot_forged period prop vote =
@@ -101,7 +101,7 @@ let ballot_forged period prop vote =
   let op = Sourced_operations (Delegate_operations {
       source = src.public_key ;
       operations = [ballot] }) in
-  forge { net_id = network } op
+  forge { chain_id = network } op
 
 let identity = P2p_identity.generate Crypto_box.default_target
 
diff --git a/src/bin_client/main_admin.ml b/src/bin_client/main_admin.ml
index 5178aed25..6df3c51e8 100644
--- a/src/bin_client/main_admin.ml
+++ b/src/bin_client/main_admin.ml
@@ -12,7 +12,7 @@ let select_commands _ _ =
     (List.flatten
        [ Client_report_commands.commands () ;
          Client_admin_commands.commands () ;
-         Client_network_commands.commands () ;
+         Client_p2p_commands.commands () ;
          Client_protocols_commands.commands () ;
          Client_rpc_commands.commands ])
 
diff --git a/src/bin_client/main_client.ml b/src/bin_client/main_client.ml
index 44c43748d..6a1a205c2 100644
--- a/src/bin_client/main_client.ml
+++ b/src/bin_client/main_client.ml
@@ -42,7 +42,7 @@ let get_commands_for_version ctxt block protocol =
 let select_commands ctxt { block ; protocol } =
   get_commands_for_version ctxt block protocol >>|? fun (_, commands_for_version)  ->
   Client_rpc_commands.commands @
-  Client_network_commands.commands () @
+  Client_p2p_commands.commands () @
   Client_keys_commands.commands () @
   Client_helpers_commands.commands () @
   commands_for_version
diff --git a/src/bin_client/test/test_multinode.sh b/src/bin_client/test/test_multinode.sh
index c03875437..5c055ca88 100755
--- a/src/bin_client/test/test_multinode.sh
+++ b/src/bin_client/test/test_multinode.sh
@@ -19,10 +19,10 @@ done
 
 for client in "${client_instances[@]}"; do
     echo
-    echo "### $client network stat"
+    echo "### $client p2p stat"
     echo
     $client bootstrapped
-    $client network stat
+    $client p2p stat
     echo
 done
 
diff --git a/src/bin_node/node_config_file.ml b/src/bin_node/node_config_file.ml
index cadf68296..3351b8fc2 100644
--- a/src/bin_node/node_config_file.ml
+++ b/src/bin_node/node_config_file.ml
@@ -14,18 +14,18 @@ let home =
   with Not_found -> "/root"
 
 let default_data_dir = home // ".tezos-node"
-let default_net_port = 9732
+let default_p2p_port = 9732
 let default_rpc_port = 8732
 
 type t = {
   data_dir : string ;
-  net : net ;
+  p2p : p2p ;
   rpc : rpc ;
   log : log ;
   shell : shell ;
 }
 
-and net = {
+and p2p = {
   expected_pow : float ;
   bootstrap_peers : string list ;
   listen_addr : string option ;
@@ -56,10 +56,10 @@ and shell = {
   block_validator_limits : Node.block_validator_limits ;
   prevalidator_limits : Node.prevalidator_limits ;
   peer_validator_limits : Node.peer_validator_limits ;
-  net_validator_limits : Node.net_validator_limits ;
+  chain_validator_limits : Node.chain_validator_limits ;
 }
 
-let default_net_limits : P2p.limits = {
+let default_p2p_limits : P2p.limits = {
   authentification_timeout = 5. ;
   min_connections = 10 ;
   expected_connections = 50 ;
@@ -82,12 +82,12 @@ let default_net_limits : P2p.limits = {
   binary_chunks_size = None ;
 }
 
-let default_net = {
+let default_p2p = {
   expected_pow = 24. ;
   bootstrap_peers  = ["bootstrap.tezos.com"] ;
-  listen_addr  = Some ("[::]:" ^ string_of_int default_net_port) ;
+  listen_addr  = Some ("[::]:" ^ string_of_int default_p2p_port) ;
   closed  = false ;
-  limits = default_net_limits ;
+  limits = default_p2p_limits ;
 }
 
 let default_rpc = {
@@ -136,7 +136,7 @@ let default_shell = {
       zombie_memory = 120. ;
     }
   } ;
-  net_validator_limits = {
+  chain_validator_limits = {
     bootstrap_threshold = 4 ;
     worker_limits = {
       backlog_size = 1000 ;
@@ -149,7 +149,7 @@ let default_shell = {
 
 let default_config = {
   data_dir = default_data_dir ;
-  net = default_net ;
+  p2p = default_p2p ;
   rpc = default_rpc ;
   log = default_log ;
   shell = default_shell ;
@@ -202,38 +202,38 @@ let limit : P2p.limits Data_encoding.t =
     (merge_objs
        (obj10
           (dft "authentification-timeout"
-             float default_net_limits.authentification_timeout)
+             float default_p2p_limits.authentification_timeout)
           (dft "min-connections" uint16
-             default_net_limits.min_connections)
+             default_p2p_limits.min_connections)
           (dft "expected-connections" uint16
-             default_net_limits.expected_connections)
+             default_p2p_limits.expected_connections)
           (dft "max-connections" uint16
-             default_net_limits.max_connections)
+             default_p2p_limits.max_connections)
           (dft "backlog" uint8
-             default_net_limits.backlog)
+             default_p2p_limits.backlog)
           (dft "max-incoming-connections" uint8
-             default_net_limits.max_incoming_connections)
+             default_p2p_limits.max_incoming_connections)
           (opt "max-download-speed" int31)
           (opt "max-upload-speed" int31)
-          (dft "swap-linger" float default_net_limits.swap_linger)
+          (dft "swap-linger" float default_p2p_limits.swap_linger)
           (opt "binary-chunks-size" uint8))
        (obj10
           (dft "read-buffer-size" int31
-             default_net_limits.read_buffer_size)
+             default_p2p_limits.read_buffer_size)
           (opt "read-queue-size" int31)
           (opt "write-queue-size" int31)
           (opt "incoming-app-message-queue-size" int31)
           (opt "incoming-message-queue-size" int31)
           (opt "outgoing-message-queue-size" int31)
           (dft "known_points_history_size" uint16
-             default_net_limits.known_points_history_size)
+             default_p2p_limits.known_points_history_size)
           (dft "known_peer_ids_history_size" uint16
-             default_net_limits.known_points_history_size)
+             default_p2p_limits.known_points_history_size)
           (opt "max_known_points" (tup2 uint16 uint16))
           (opt "max_known_peer_ids" (tup2 uint16 uint16))
        ))
 
-let net =
+let p2p =
   let open Data_encoding in
   conv
     (fun { expected_pow ; bootstrap_peers ;
@@ -245,12 +245,12 @@ let net =
       { expected_pow ; bootstrap_peers ;
         listen_addr ; closed ; limits })
     (obj5
-       (dft "expected-proof-of-work" float default_net.expected_pow)
+       (dft "expected-proof-of-work" float default_p2p.expected_pow)
        (dft "bootstrap-peers"
-          (list string) default_net.bootstrap_peers)
+          (list string) default_p2p.bootstrap_peers)
        (opt "listen-addr" string)
        (dft "closed" bool false)
-       (dft "limits" limit default_net_limits))
+       (dft "limits" limit default_p2p_limits))
 
 let rpc : rpc Data_encoding.t =
   let open Data_encoding in
@@ -389,7 +389,7 @@ let peer_validator_limits_encoding =
           default_limits.worker_limits.zombie_lifetime
           default_limits.worker_limits.zombie_memory))
 
-let net_validator_limits_encoding =
+let chain_validator_limits_encoding =
   let open Data_encoding in
   conv
     (fun { Node.bootstrap_threshold ; worker_limits } ->
@@ -399,42 +399,42 @@ let net_validator_limits_encoding =
     (merge_objs
        (obj1
           (dft "bootstrap_threshold" uint8
-             default_shell.net_validator_limits.bootstrap_threshold))
+             default_shell.chain_validator_limits.bootstrap_threshold))
        (worker_limits_encoding
-          default_shell.net_validator_limits.worker_limits.backlog_size
-          default_shell.net_validator_limits.worker_limits.backlog_level
-          default_shell.net_validator_limits.worker_limits.zombie_lifetime
-          default_shell.net_validator_limits.worker_limits.zombie_memory))
+          default_shell.chain_validator_limits.worker_limits.backlog_size
+          default_shell.chain_validator_limits.worker_limits.backlog_level
+          default_shell.chain_validator_limits.worker_limits.zombie_lifetime
+          default_shell.chain_validator_limits.worker_limits.zombie_memory))
 
 let shell =
   let open Data_encoding in
   conv
     (fun { peer_validator_limits ; block_validator_limits ;
-           prevalidator_limits ; net_validator_limits } ->
+           prevalidator_limits ; chain_validator_limits } ->
       (peer_validator_limits, block_validator_limits,
-       prevalidator_limits, net_validator_limits))
+       prevalidator_limits, chain_validator_limits))
     (fun (peer_validator_limits, block_validator_limits,
-          prevalidator_limits, net_validator_limits) ->
+          prevalidator_limits, chain_validator_limits) ->
       { peer_validator_limits ; block_validator_limits ;
-        prevalidator_limits ; net_validator_limits })
+        prevalidator_limits ; chain_validator_limits })
     (obj4
        (dft "peer_validator" peer_validator_limits_encoding default_shell.peer_validator_limits)
        (dft "block_validator" block_validator_limits_encoding default_shell.block_validator_limits)
        (dft "prevalidator" prevalidator_limits_encoding default_shell.prevalidator_limits)
-       (dft "net_validator" net_validator_limits_encoding default_shell.net_validator_limits)
+       (dft "chain_validator" chain_validator_limits_encoding default_shell.chain_validator_limits)
     )
 
 let encoding =
   let open Data_encoding in
   conv
-    (fun { data_dir ; rpc ; net ; log ; shell } ->
-       (data_dir, rpc, net, log, shell))
-    (fun (data_dir, rpc, net, log, shell) ->
-       { data_dir ; rpc ; net ; log ; shell })
+    (fun { data_dir ; rpc ; p2p ; log ; shell } ->
+       (data_dir, rpc, p2p, log, shell))
+    (fun (data_dir, rpc, p2p, log, shell) ->
+       { data_dir ; rpc ; p2p ; log ; shell })
     (obj5
        (dft "data-dir" string default_data_dir)
        (dft "rpc" rpc default_rpc)
-       (req "net" net)
+       (req "p2p" p2p)
        (dft "log" log default_log)
        (dft "shell" shell default_shell))
 
@@ -482,42 +482,42 @@ let update
     | [] -> default
     | l -> l in
   let limits : P2p.limits = {
-    cfg.net.limits with
+    cfg.p2p.limits with
     min_connections =
       Option.unopt
-        ~default:cfg.net.limits.min_connections
+        ~default:cfg.p2p.limits.min_connections
         min_connections ;
     expected_connections =
       Option.unopt
-        ~default:cfg.net.limits.expected_connections
+        ~default:cfg.p2p.limits.expected_connections
         expected_connections ;
     max_connections =
       Option.unopt
-        ~default:cfg.net.limits.max_connections
+        ~default:cfg.p2p.limits.max_connections
         max_connections ;
     max_download_speed =
       Option.first_some
-        max_download_speed cfg.net.limits.max_download_speed ;
+        max_download_speed cfg.p2p.limits.max_download_speed ;
     max_upload_speed =
       Option.first_some
-        max_upload_speed cfg.net.limits.max_upload_speed ;
+        max_upload_speed cfg.p2p.limits.max_upload_speed ;
     max_known_points =
       Option.first_some
-        peer_table_size cfg.net.limits.max_known_points ;
+        peer_table_size cfg.p2p.limits.max_known_points ;
     max_known_peer_ids =
       Option.first_some
-        peer_table_size cfg.net.limits.max_known_peer_ids ;
+        peer_table_size cfg.p2p.limits.max_known_peer_ids ;
     binary_chunks_size =
       Option.map ~f:(fun x -> x lsl 10) binary_chunks_size ;
   } in
-  let net : net = {
+  let p2p : p2p = {
     expected_pow =
-      Option.unopt ~default:cfg.net.expected_pow expected_pow ;
+      Option.unopt ~default:cfg.p2p.expected_pow expected_pow ;
     bootstrap_peers =
-      Option.unopt ~default:cfg.net.bootstrap_peers bootstrap_peers ;
+      Option.unopt ~default:cfg.p2p.bootstrap_peers bootstrap_peers ;
     listen_addr =
-      Option.first_some listen_addr cfg.net.listen_addr ;
-    closed = cfg.net.closed || closed ;
+      Option.first_some listen_addr cfg.p2p.listen_addr ;
+    closed = cfg.p2p.closed || closed ;
     limits ;
   }
   and rpc : rpc = {
@@ -538,16 +538,16 @@ let update
     peer_validator_limits = cfg.shell.peer_validator_limits ;
     block_validator_limits = cfg.shell.block_validator_limits ;
     prevalidator_limits = cfg.shell.prevalidator_limits ;
-    net_validator_limits =
+    chain_validator_limits =
       Option.unopt_map
-        ~default:cfg.shell.net_validator_limits
+        ~default:cfg.shell.chain_validator_limits
         ~f:(fun bootstrap_threshold ->
-            { cfg.shell.net_validator_limits
+            { cfg.shell.chain_validator_limits
               with bootstrap_threshold })
         bootstrap_threshold
   }
   in
-  return { data_dir ; net ; rpc ; log ; shell }
+  return { data_dir ; p2p ; rpc ; log ; shell }
 
 let resolve_addr ?default_port ?(passive = false) peer =
   let addr, port = P2p_point.Id.parse_addr_port peer in
@@ -568,7 +568,7 @@ let resolve_addrs ?default_port ?passive peers =
 
 let resolve_listening_addrs listen_addr =
   resolve_addr
-    ~default_port:default_net_port
+    ~default_port:default_p2p_port
     ~passive:true
     listen_addr
 
@@ -580,10 +580,10 @@ let resolve_rpc_listening_addrs listen_addr =
 
 let resolve_bootstrap_addrs peers =
   resolve_addrs
-    ~default_port:default_net_port
+    ~default_port:default_p2p_port
     peers
 let check_listening_addr config =
-  match config.net.listen_addr with
+  match config.p2p.listen_addr with
   | None -> Lwt.return_unit
   | Some addr ->
       Lwt.catch begin fun () ->
@@ -635,7 +635,7 @@ let check_bootstrap_peer addr =
 
 
 let check_bootstrap_peers config =
-  Lwt_list.iter_p check_bootstrap_peer config.net.bootstrap_peers
+  Lwt_list.iter_p check_bootstrap_peer config.p2p.bootstrap_peers
 
 let check config =
   check_listening_addr config >>= fun () ->
diff --git a/src/bin_node/node_config_file.mli b/src/bin_node/node_config_file.mli
index f296ef761..b11479352 100644
--- a/src/bin_node/node_config_file.mli
+++ b/src/bin_node/node_config_file.mli
@@ -9,13 +9,13 @@
 
 type t = {
   data_dir : string ;
-  net : net ;
+  p2p : p2p ;
   rpc : rpc ;
   log : log ;
   shell : shell ;
 }
 
-and net = {
+and p2p = {
   expected_pow : float ;
   bootstrap_peers : string list ;
   listen_addr : string option ;
@@ -46,13 +46,13 @@ and shell = {
   block_validator_limits : Node.block_validator_limits ;
   prevalidator_limits : Node.prevalidator_limits ;
   peer_validator_limits : Node.peer_validator_limits ;
-  net_validator_limits : Node.net_validator_limits ;
+  chain_validator_limits : Node.chain_validator_limits ;
 }
 
 val default_data_dir: string
-val default_net_port: int
+val default_p2p_port: int
 val default_rpc_port: int
-val default_net: net
+val default_p2p: p2p
 val default_config: t
 
 val update:
diff --git a/src/bin_node/node_identity_command.ml b/src/bin_node/node_identity_command.ml
index a79df3075..d9034cd8f 100644
--- a/src/bin_node/node_identity_command.ml
+++ b/src/bin_node/node_identity_command.ml
@@ -18,13 +18,13 @@ let show { Node_config_file.data_dir } =
   Format.printf "Peer_id: %a.@." P2p_peer.Id.pp id.peer_id ;
   return ()
 
-let generate { Node_config_file.data_dir ; net } =
+let generate { Node_config_file.data_dir ; p2p } =
   let identity_file = identity_file data_dir in
   if Sys.file_exists identity_file then
     fail (Node_identity_file.Existent_identity_file identity_file)
   else
-    let target = Crypto_box.make_target net.expected_pow in
-    Format.eprintf "Generating a new identity... (level: %.2f) " net.expected_pow ;
+    let target = Crypto_box.make_target p2p.expected_pow in
+    Format.eprintf "Generating a new identity... (level: %.2f) " p2p.expected_pow ;
     let id =
       P2p_identity.generate_with_animation Format.err_formatter target in
     Node_identity_file.write identity_file id >>=? fun () ->
@@ -33,7 +33,7 @@ let generate { Node_config_file.data_dir ; net } =
       P2p_peer.Id.pp id.peer_id identity_file ;
     return ()
 
-let check { Node_config_file.data_dir ; net = { expected_pow } } =
+let check { Node_config_file.data_dir ; p2p = { expected_pow } } =
   Node_identity_file.read
     ~expected_pow (identity_file data_dir) >>=? fun id ->
   Format.printf
diff --git a/src/bin_node/node_run_command.ml b/src/bin_node/node_run_command.ml
index 28bf0b847..9ff2ec401 100644
--- a/src/bin_node/node_run_command.ml
+++ b/src/bin_node/node_run_command.ml
@@ -9,7 +9,7 @@
 
 open Logging.Node.Main
 
-let genesis : State.Net.genesis = {
+let genesis : State.Chain.genesis = {
   time =
     Time.of_notation_exn "2017-10-19T00:00:00Z" ;
   block =
@@ -120,7 +120,7 @@ let init_node ?sandbox (config : Node_config_file.t) =
   end >>= fun patch_context ->
   (* TODO "WARN" when pow is below our expectation. *)
   begin
-    match config.net.listen_addr with
+    match config.p2p.listen_addr with
     | None ->
         lwt_log_notice "Not listening to P2P calls." >>= fun () ->
         return (None, None)
@@ -140,7 +140,7 @@ let init_node ?sandbox (config : Node_config_file.t) =
     | None, Some _ -> return None
     | _ ->
         (Node_config_file.resolve_bootstrap_addrs
-           config.net.bootstrap_peers) >>= fun trusted_points ->
+           config.p2p.bootstrap_peers) >>= fun trusted_points ->
         Node_identity_file.read
           (config.data_dir //
            Node_data_version.default_identity_file_name) >>=? fun identity ->
@@ -153,13 +153,13 @@ let init_node ?sandbox (config : Node_config_file.t) =
             trusted_points ;
             peers_file =
               (config.data_dir // "peers.json") ;
-            closed_network = config.net.closed ;
+            closed_network = config.p2p.closed ;
             identity ;
             proof_of_work_target =
-              Crypto_box.make_target config.net.expected_pow ;
+              Crypto_box.make_target config.p2p.expected_pow ;
           }
         in
-        return (Some (p2p_config, config.net.limits))
+        return (Some (p2p_config, config.p2p.limits))
   end >>=? fun p2p_config ->
   let node_config : Node.config = {
     genesis ;
@@ -167,14 +167,14 @@ let init_node ?sandbox (config : Node_config_file.t) =
     store_root = store_dir config.data_dir ;
     context_root = context_dir config.data_dir ;
     p2p = p2p_config ;
-    test_network_max_tll = Some (48 * 3600) ; (* 2 days *)
+    test_chain_max_tll = Some (48 * 3600) ; (* 2 days *)
   } in
   Node.create
     node_config
     config.shell.peer_validator_limits
     config.shell.block_validator_limits
     config.shell.prevalidator_limits
-    config.shell.net_validator_limits
+    config.shell.chain_validator_limits
 
 let () =
   let old_hook = !Lwt.async_exception_hook in
diff --git a/src/bin_node/node_shared_arg.ml b/src/bin_node/node_shared_arg.ml
index 6c5c3867b..dc0fd0d31 100644
--- a/src/bin_node/node_shared_arg.ml
+++ b/src/bin_node/node_shared_arg.ml
@@ -87,11 +87,11 @@ let wrap
 module Manpage = struct
 
   let misc_section = "MISC OPTIONS"
-  let network_section = "NETWORK OPTIONS"
+  let p2p_section = "P2P OPTIONS"
   let rpc_section = "RPC OPTIONS"
 
   let args = [
-    `S network_section ;
+    `S p2p_section ;
     `S rpc_section ;
     `S misc_section ;
   ]
@@ -133,9 +133,9 @@ module Term = struct
     Arg.(value & opt (some string) None &
          info ~docs ~doc ~docv:"FILE" ["config-file"])
 
-  (* net args *)
+  (* P2p args *)
 
-  let docs = Manpage.network_section
+  let docs = Manpage.p2p_section
 
   let connections =
     let doc =
@@ -270,7 +270,7 @@ let read_and_patch_config_file ?(ignore_bootstrap_peers=false) args =
       log_info "Ignoring bootstrap peers" ;
       peers
     end else
-      cfg.net.bootstrap_peers @ peers in
+      cfg.p2p.bootstrap_peers @ peers in
   Node_config_file.update
     ?data_dir ?min_connections ?expected_connections ?max_connections
     ?max_download_speed ?max_upload_speed ?binary_chunks_size
diff --git a/src/lib_base/net_id.ml b/src/lib_base/chain_id.ml
similarity index 97%
rename from src/lib_base/net_id.ml
rename to src/lib_base/chain_id.ml
index aed7ee66e..a902e5861 100644
--- a/src/lib_base/net_id.ml
+++ b/src/lib_base/chain_id.ml
@@ -11,7 +11,7 @@ module Raw = struct
 
   type t = string
 
-  let name = "Net_id"
+  let name = "Chain_id"
   let title = "Network identifier"
 
   let extract bh =
@@ -83,7 +83,7 @@ module Raw = struct
 
   let b58check_encoding =
     Tezos_crypto.Base58.register_encoding
-      ~prefix: Tezos_crypto.Base58.Prefix.net_id
+      ~prefix: Tezos_crypto.Base58.Prefix.chain_id
       ~length: size
       ~wrap: (fun s -> Hash s)
       ~of_raw:of_string ~to_raw: (fun h -> h)
diff --git a/src/lib_base/net_id.mli b/src/lib_base/chain_id.mli
similarity index 100%
rename from src/lib_base/net_id.mli
rename to src/lib_base/chain_id.mli
diff --git a/src/lib_base/protocol_environment.ml b/src/lib_base/protocol_environment.ml
index 2b40ff836..6c8f746d3 100644
--- a/src/lib_base/protocol_environment.ml
+++ b/src/lib_base/protocol_environment.ml
@@ -52,7 +52,7 @@ module type UPDATER = sig
 
   val compile: Protocol_hash.t -> Protocol.t -> bool Lwt.t
   val activate: Context.t -> Protocol_hash.t -> Context.t Lwt.t
-  val fork_test_network:
+  val fork_test_chain:
     Context.t -> protocol:Protocol_hash.t -> expiration:Time.t -> Context.t Lwt.t
 
 end
diff --git a/src/lib_base/protocol_environment.mli b/src/lib_base/protocol_environment.mli
index 664102f3b..f0d56bb07 100644
--- a/src/lib_base/protocol_environment.mli
+++ b/src/lib_base/protocol_environment.mli
@@ -45,7 +45,7 @@ module type UPDATER = sig
 
   val compile: Protocol_hash.t -> Protocol.t -> bool Lwt.t
   val activate: Context.t -> Protocol_hash.t -> Context.t Lwt.t
-  val fork_test_network:
+  val fork_test_chain:
     Context.t -> protocol:Protocol_hash.t -> expiration:Time.t -> Context.t Lwt.t
 
 end
diff --git a/src/lib_base/test_network_status.ml b/src/lib_base/test_chain_status.ml
similarity index 83%
rename from src/lib_base/test_network_status.ml
rename to src/lib_base/test_chain_status.ml
index 7877b75fe..d3550bfb3 100644
--- a/src/lib_base/test_network_status.ml
+++ b/src/lib_base/test_chain_status.ml
@@ -14,7 +14,7 @@ type t =
       expiration: Time.t ;
     }
   | Running of {
-      net_id: Net_id.t ;
+      chain_id: Chain_id.t ;
       genesis: Block_hash.t ;
       protocol: Protocol_hash.t ;
       expiration: Time.t ;
@@ -41,16 +41,16 @@ let encoding =
     case (Tag 2)
       (obj5
          (req "status" (constant "running"))
-         (req "net_id" Net_id.encoding)
+         (req "chain_id" Chain_id.encoding)
          (req "genesis" Block_hash.encoding)
          (req "protocol" Protocol_hash.encoding)
          (req "expiration" Time.encoding))
       (function
-        | Running { net_id ; genesis ; protocol ; expiration } ->
-            Some ((), net_id, genesis, protocol, expiration)
+        | Running { chain_id ; genesis ; protocol ; expiration } ->
+            Some ((), chain_id, genesis, protocol, expiration)
         | _ -> None)
-      (fun ((), net_id, genesis, protocol, expiration) ->
-         Running { net_id ; genesis ; protocol ; expiration }) ;
+      (fun ((), chain_id, genesis, protocol, expiration) ->
+         Running { chain_id ; genesis ; protocol ; expiration }) ;
   ]
 
 let pp ppf = function
@@ -62,7 +62,7 @@ let pp ppf = function
         protocol
         Time.pp_hum
         expiration
-  | Running { net_id ; genesis ; protocol ; expiration } ->
+  | Running { chain_id ; genesis ; protocol ; expiration } ->
       Format.fprintf ppf
         "@[<v 2>Running %a\
          @ Genesis: %a\
@@ -70,5 +70,5 @@ let pp ppf = function
          @ Expiration: %a@]"
         Protocol_hash.pp protocol
         Block_hash.pp genesis
-        Net_id.pp net_id
+        Chain_id.pp chain_id
         Time.pp_hum expiration
diff --git a/src/lib_base/test_network_status.mli b/src/lib_base/test_chain_status.mli
similarity index 96%
rename from src/lib_base/test_network_status.mli
rename to src/lib_base/test_chain_status.mli
index 03907fcf2..12670227c 100644
--- a/src/lib_base/test_network_status.mli
+++ b/src/lib_base/test_chain_status.mli
@@ -14,7 +14,7 @@ type t =
       expiration: Time.t ;
     }
   | Running of {
-      net_id: Net_id.t ;
+      chain_id: Chain_id.t ;
       genesis: Block_hash.t ;
       protocol: Protocol_hash.t ;
       expiration: Time.t ;
diff --git a/src/lib_base/tzPervasives.ml b/src/lib_base/tzPervasives.ml
index 33849e003..4cf06a14d 100644
--- a/src/lib_base/tzPervasives.ml
+++ b/src/lib_base/tzPervasives.ml
@@ -33,7 +33,7 @@ module Block_header = Block_header
 module Operation = Operation
 module Protocol = Protocol
 
-module Net_id = Net_id
+module Chain_id = Chain_id
 module Block_hash = Block_hash
 module Operation_hash = Operation_hash
 module Operation_list_hash = Operation_list_hash
@@ -41,7 +41,7 @@ module Operation_list_list_hash = Operation_list_list_hash
 module Context_hash = Context_hash
 module Protocol_hash = Protocol_hash
 
-module Test_network_status = Test_network_status
+module Test_chain_status = Test_chain_status
 module Preapply_result = Preapply_result
 
 module Block_locator = Block_locator
diff --git a/src/lib_base/tzPervasives.mli b/src/lib_base/tzPervasives.mli
index fd66bf8c3..3f60cef4e 100644
--- a/src/lib_base/tzPervasives.mli
+++ b/src/lib_base/tzPervasives.mli
@@ -31,12 +31,12 @@ module Fitness = Fitness
 module Block_header = Block_header
 module Operation = Operation
 module Protocol = Protocol
-module Test_network_status = Test_network_status
+module Test_chain_status = Test_chain_status
 module Preapply_result = Preapply_result
 module Block_locator = Block_locator
 module Mempool = Mempool
 
-module Net_id = Net_id
+module Chain_id = Chain_id
 module Block_hash = Block_hash
 module Operation_hash = Operation_hash
 module Operation_list_hash = Operation_list_hash
diff --git a/src/lib_client_base_unix/client_signer_unencrypted.ml b/src/lib_client_base_unix/client_signer_unencrypted.ml
index 8125ad26f..7a7080f8c 100644
--- a/src/lib_client_base_unix/client_signer_unencrypted.ml
+++ b/src/lib_client_base_unix/client_signer_unencrypted.ml
@@ -16,7 +16,7 @@ module Unencrypted_signer : SIGNER = struct
     "Built-in signer using raw unencrypted keys."
 
   let description =
-    "Do not use this signer except for playing on the test network.\n\
+    "Do not use this signer except for playing on the test chain.\n\
      The format for importing secret keys is either no argument (will \
      generate a key) or the raw Base58-encoded key (starting with \
      'edsk').\n\
diff --git a/src/lib_client_commands/client_network_commands.ml b/src/lib_client_commands/client_p2p_commands.ml
similarity index 93%
rename from src/lib_client_commands/client_network_commands.ml
rename to src/lib_client_commands/client_p2p_commands.ml
index fc2f31bf7..fe42e8356 100644
--- a/src/lib_client_commands/client_network_commands.ml
+++ b/src/lib_client_commands/client_p2p_commands.ml
@@ -8,14 +8,14 @@
 (**************************************************************************)
 
 let group =
-  { Cli_entries.name = "network" ;
-    title = "Commands for monitoring and controlling network state" }
+  { Cli_entries.name = "p2p" ;
+    title = "Commands for monitoring and controlling p2p-layer state" }
 
 let commands () = [
   let open Cli_entries in
   command ~group ~desc: "show global network status"
     no_options
-    (prefixes ["network" ; "stat"] stop) begin fun () (cctxt : #Client_context.full_context) ->
+    (prefixes ["p2p" ; "stat"] stop) begin fun () (cctxt : #Client_context.full_context) ->
     P2p_services.stat cctxt >>=? fun stat ->
     P2p_services.Connections.list cctxt >>=? fun conns ->
     P2p_services.Peers.list cctxt >>=? fun peers ->
diff --git a/src/lib_client_commands/client_network_commands.mli b/src/lib_client_commands/client_p2p_commands.mli
similarity index 100%
rename from src/lib_client_commands/client_network_commands.mli
rename to src/lib_client_commands/client_p2p_commands.mli
diff --git a/src/lib_client_commands/client_report_commands.ml b/src/lib_client_commands/client_report_commands.ml
index 52b4690ef..6658ba21e 100644
--- a/src/lib_client_commands/client_report_commands.ml
+++ b/src/lib_client_commands/client_report_commands.ml
@@ -10,13 +10,13 @@
 (* Commands used to introspect the node's state *)
 
 let pp_block ppf
-    { Block_services.hash ; net_id ; level ;
+    { Block_services.hash ; chain_id ; level ;
       proto_level ; predecessor ; timestamp ;
       operations_hash ; fitness ; data ;
-      operations ; protocol ; test_network } =
+      operations ; protocol ; test_chain } =
   Format.fprintf ppf
     "@[<v 2>Hash: %a\
-     @ Test network: %a\
+     @ Test chain: %a\
      @ Level: %ld\
      @ Proto_level: %d\
      @ Predecessor: %a\
@@ -28,12 +28,12 @@ let pp_block ppf
      @ Operations: @[<v>%a@]\
      @ Data (hex encoded): \"%a\"@]"
     Block_hash.pp hash
-    Test_network_status.pp test_network
+    Test_chain_status.pp test_chain
     level
     proto_level
     Block_hash.pp predecessor
     Protocol_hash.pp protocol
-    Net_id.pp net_id
+    Chain_id.pp chain_id
     Time.pp_hum timestamp
     Fitness.pp fitness
     Operation_list_list_hash.pp operations_hash
diff --git a/src/lib_crypto/base58.ml b/src/lib_crypto/base58.ml
index 757a5ac26..af54c2dd2 100644
--- a/src/lib_crypto/base58.ml
+++ b/src/lib_crypto/base58.ml
@@ -319,6 +319,6 @@ module Prefix = struct
   let ed25519_signature = "\009\245\205\134\018" (* edsig(99) *)
 
   (* 4 *)
-  let net_id = "\087\082\000" (* Net(15) *)
+  let chain_id = "\087\082\000" (* Net(15) *)
 
 end
diff --git a/src/lib_crypto/base58.mli b/src/lib_crypto/base58.mli
index d9c4b7557..6ccc224d3 100644
--- a/src/lib_crypto/base58.mli
+++ b/src/lib_crypto/base58.mli
@@ -23,7 +23,7 @@ module Prefix : sig
   val ed25519_public_key: string
   val ed25519_secret_key: string
   val ed25519_signature: string
-  val net_id: string
+  val chain_id: string
 
 end
 
diff --git a/src/lib_protocol_environment_client/fake_updater.ml b/src/lib_protocol_environment_client/fake_updater.ml
index 43cac36c9..7d2298cd9 100644
--- a/src/lib_protocol_environment_client/fake_updater.ml
+++ b/src/lib_protocol_environment_client/fake_updater.ml
@@ -73,6 +73,6 @@ module Make(Context : Protocol_environment.CONTEXT) = struct
 
   let compile _ _ = assert false
   let activate _ _ = assert false
-  let fork_test_network _ ~protocol:_ ~expiration:_ = assert false
+  let fork_test_chain _ ~protocol:_ ~expiration:_ = assert false
 
 end
diff --git a/src/lib_protocol_environment_sigs/v1/lwt_sequence.mli b/src/lib_protocol_environment_sigs/v1/lwt_sequence.mli
index 214be9dc3..6271654fd 100644
--- a/src/lib_protocol_environment_sigs/v1/lwt_sequence.mli
+++ b/src/lib_protocol_environment_sigs/v1/lwt_sequence.mli
@@ -58,7 +58,7 @@ val is_empty : 'a t -> bool
 (** Returns [true] iff the given sequence is empty *)
 
 val length : 'a t -> int
-(** Returns the number of elemenets in the given sequence. This is a
+(** Returns the number of elements in the given sequence. This is a
     O(n) operation where [n] is the number of elements in the
     sequence. *)
 
diff --git a/src/lib_protocol_environment_sigs/v1/updater.mli b/src/lib_protocol_environment_sigs/v1/updater.mli
index 505feb6cc..f4b3ffa3a 100644
--- a/src/lib_protocol_environment_sigs/v1/updater.mli
+++ b/src/lib_protocol_environment_sigs/v1/updater.mli
@@ -95,7 +95,7 @@ module type PROTOCOL = sig
 
   (** Checks that a block is well formed in a given context. This
       function should run quickly, as its main use is to reject bad
-      blocks from the network as early as possible. The input context
+      blocks from the chain as early as possible. The input context
       is the one resulting of an ancestor block of same protocol
       version, not necessarily the one of its predecessor. *)
   val precheck_block:
@@ -169,10 +169,10 @@ val compile: Protocol_hash.t -> Protocol.t -> bool Lwt.t
     been previously compiled successfully. *)
 val activate: Context.t -> Protocol_hash.t -> Context.t Lwt.t
 
-(** Fork a test network. The forkerd network will use the current block
-    as genesis, and [protocol] as economic protocol. The network will
+(** Fork a test chain. The forkerd chain will use the current block
+    as genesis, and [protocol] as economic protocol. The chain will
     be destroyed when a (successor) block will have a timestamp greater
     than [expiration]. The protocol must have been previously compiled
     successfully. *)
-val fork_test_network:
+val fork_test_chain:
   Context.t -> protocol:Protocol_hash.t -> expiration:Time.t -> Context.t Lwt.t
diff --git a/src/lib_protocol_updater/updater.ml b/src/lib_protocol_updater/updater.ml
index 894c949f3..c3beaeeca 100644
--- a/src/lib_protocol_updater/updater.ml
+++ b/src/lib_protocol_updater/updater.ml
@@ -35,7 +35,7 @@ module Raw = struct
   }
 
   let activate = Context.set_protocol
-  let fork_test_network = Context.fork_test_network
+  let fork_test_chain = Context.fork_test_chain
 
   (** Compiler *)
 
diff --git a/src/lib_protocol_updater/updater.mli b/src/lib_protocol_updater/updater.mli
index 82c2cb716..a7b85b5ec 100644
--- a/src/lib_protocol_updater/updater.mli
+++ b/src/lib_protocol_updater/updater.mli
@@ -11,7 +11,7 @@
 
 val compile: Protocol_hash.t -> Protocol.t -> bool Lwt.t
 val activate: Context.t -> Protocol_hash.t -> Context.t Lwt.t
-val fork_test_network:
+val fork_test_chain:
   Context.t -> protocol:Protocol_hash.t -> expiration:Time.t -> Context.t Lwt.t
 
 val init: string -> unit
diff --git a/src/lib_shell/block_locator_iterator.ml b/src/lib_shell/block_locator_iterator.ml
index 923009816..c20c3fb8c 100644
--- a/src/lib_shell/block_locator_iterator.ml
+++ b/src/lib_shell/block_locator_iterator.ml
@@ -49,45 +49,45 @@ let to_steps locator =
     end
     [] locator
 
-let block_validity net_state block : Block_locator.validity Lwt.t =
-  State.Block.known net_state block >>= function
+let block_validity chain_state block : Block_locator.validity Lwt.t =
+  State.Block.known chain_state block >>= function
   | false ->
-      if Block_hash.equal block (State.Net.faked_genesis_hash net_state) then
+      if Block_hash.equal block (State.Chain.faked_genesis_hash chain_state) then
         Lwt.return Block_locator.Known_valid
       else
         Lwt.return Block_locator.Unknown
   | true ->
-      State.Block.known_invalid net_state block >>= function
+      State.Block.known_invalid chain_state block >>= function
       | true ->
           Lwt.return Block_locator.Known_invalid
       | false ->
           Lwt.return Block_locator.Known_valid
 
-let known_ancestor net_state locator =
-  Block_locator.unknown_prefix (block_validity net_state) locator >>= function
+let known_ancestor chain_state locator =
+  Block_locator.unknown_prefix (block_validity chain_state) locator >>= function
   | None -> Lwt.return_none
   | Some (tail, locator) ->
-      if Block_hash.equal tail (State.Net.faked_genesis_hash net_state) then
+      if Block_hash.equal tail (State.Chain.faked_genesis_hash chain_state) then
         State.Block.read_exn
-          net_state (State.Net.genesis net_state).block >>= fun genesis ->
+          chain_state (State.Chain.genesis chain_state).block >>= fun genesis ->
         Lwt.return_some (genesis, locator)
       else
-        State.Block.read_exn net_state tail >>= fun block ->
+        State.Block.read_exn chain_state tail >>= fun block ->
         Lwt.return_some (block, locator)
 
-let find_new net_state locator sz =
+let find_new chain_state locator sz =
   let rec path sz acc h =
     if sz <= 0 then Lwt.return (List.rev acc)
     else
-      State.read_chain_store net_state begin fun chain_store _data ->
-        Store.Chain.In_chain.read_opt (chain_store, h)
+      State.read_chain_data chain_state begin fun chain_store _data ->
+        Store.Chain_data.In_main_branch.read_opt (chain_store, h)
       end >>= function
       | None -> Lwt.return (List.rev acc)
       | Some s -> path (sz-1) (s :: acc) s in
-  known_ancestor net_state locator >>= function
+  known_ancestor chain_state locator >>= function
   | None -> Lwt.return_nil
   | Some (known, _) ->
-      Chain.head net_state >>= fun head ->
+      Chain.head chain_state >>= fun head ->
       Chain_traversal.common_ancestor known head >>= fun ancestor ->
       path sz [] (State.Block.hash ancestor)
 
diff --git a/src/lib_shell/block_locator_iterator.mli b/src/lib_shell/block_locator_iterator.mli
index 54ee1ae3b..a97cc6e64 100644
--- a/src/lib_shell/block_locator_iterator.mli
+++ b/src/lib_shell/block_locator_iterator.mli
@@ -40,16 +40,16 @@ val estimated_length: Block_locator.t -> int
     represented by [locator]. *)
 
 val known_ancestor:
-  State.Net.t -> Block_locator.t -> (State.Block.t * Block_locator.t) option Lwt.t
-(** [known_ancestor net_state locator] computes the first block of
+  State.Chain.t -> Block_locator.t -> (State.Block.t * Block_locator.t) option Lwt.t
+(** [known_ancestor chain_state locator] computes the first block of
     [locator] that is known to be a valid block. It also computes the
     'prefix' of [locator] with end at the first valid block.  The
     function returns [None] when no block in the locator are known or
     if the first known block is invalid. *)
 
 val find_new:
-  State.Net.t -> Block_locator.t -> int -> Block_hash.t list Lwt.t
-(** [find_new net locator max_length] returns the blocks from our
+  State.Chain.t -> Block_locator.t -> int -> Block_hash.t list Lwt.t
+(** [find_new chain locator max_length] returns the blocks from our
     current branch that would be unknown to a peer that sends us the
     [locator]. *)
 
diff --git a/src/lib_shell/block_validator.ml b/src/lib_shell/block_validator.ml
index f7086c575..696f6ff77 100644
--- a/src/lib_shell/block_validator.ml
+++ b/src/lib_shell/block_validator.ml
@@ -37,7 +37,7 @@ module Request = struct
   include Request
   type 'a t =
     | Request_validation : {
-        net_db: Distributed_db.net_db ;
+        chain_db: Distributed_db.chain_db ;
         notify_new_block: State.Block.t -> unit ;
         canceler: Lwt_canceler.t option ;
         peer: P2p_peer.Id.t option ;
@@ -47,9 +47,9 @@ module Request = struct
       } -> State.Block.t tzresult t
   let view
     : type a. a t -> view
-    = fun (Request_validation { net_db ; peer ; hash }) ->
-      let net_id = net_db |> Distributed_db.net_state |> State.Net.id in
-      { net_id ; block = hash ; peer = peer }
+    = fun (Request_validation { chain_db ; peer ; hash }) ->
+      let chain_id = chain_db |> Distributed_db.chain_state |> State.Chain.id in
+      { chain_id ; block = hash ; peer = peer }
 end
 
 module Worker = Worker.Make (Name) (Event) (Request) (Types)
@@ -98,9 +98,9 @@ let assert_operation_liveness block live_blocks operations =
                               originating_block = op.shell.branch })))
     operations
 
-let check_liveness net_state pred hash operations_hashes operations =
+let check_liveness chain_state pred hash operations_hashes operations =
   begin
-    Chain.data net_state >>= fun chain_data ->
+    Chain.data chain_state >>= fun chain_data ->
     if State.Block.equal chain_data.current_head pred then
       Lwt.return (chain_data.live_blocks, chain_data.live_operations)
     else
@@ -113,7 +113,7 @@ let check_liveness net_state pred hash operations_hashes operations =
   return ()
 
 let apply_block
-    net_state
+    chain_state
     pred (module Proto : Registred_protocol.T)
     hash (header: Block_header.t)
     operations =
@@ -141,7 +141,7 @@ let apply_block
        return ())
     operations Proto.validation_passes >>=? fun () ->
   let operation_hashes = List.map (List.map Operation.hash) operations in
-  check_liveness net_state pred hash operation_hashes operations >>=? fun () ->
+  check_liveness chain_state pred hash operation_hashes operations >>=? fun () ->
   mapi2_s (fun pass -> map2_s begin fun op_hash raw ->
       Lwt.return (Proto.parse_operation op_hash raw)
       |> trace (invalid_block hash (Cannot_parse_operation op_hash)) >>=? fun op ->
@@ -155,7 +155,7 @@ let apply_block
     operation_hashes
     operations >>=? fun parsed_operations ->
   State.Block.context pred >>= fun pred_context ->
-  Context.reset_test_network
+  Context.reset_test_chain
     pred_context pred_hash header.shell.timestamp >>= fun context ->
   (* TODO wrap 'proto_error' into 'block_error' *)
   Proto.begin_application
@@ -194,14 +194,14 @@ let apply_block
     { new_context with max_operations_ttl } in
   return new_context
 
-let check_net_liveness net_db hash (header: Block_header.t) =
-  let net_state = Distributed_db.net_state net_db in
-  match State.Net.expiration net_state with
+let check_chain_liveness chain_db hash (header: Block_header.t) =
+  let chain_state = Distributed_db.chain_state chain_db in
+  match State.Chain.expiration chain_state with
   | Some eol when Time.(eol <= header.shell.timestamp) ->
       fail @@ invalid_block hash @@
-      Expired_network { net_id = State.Net.id net_state ;
-                        expiration = eol ;
-                        timestamp = header.shell.timestamp }
+      Expired_chain { chain_id = State.Chain.id chain_state ;
+                      expiration = eol ;
+                      timestamp = header.shell.timestamp }
   | None | Some _ -> return ()
 
 let get_proto pred hash =
@@ -217,11 +217,11 @@ let on_request
   : type r. t -> r Request.t -> r tzresult Lwt.t
   = fun w
     (Request.Request_validation
-       { net_db ; notify_new_block ; canceler ;
+       { chain_db ; notify_new_block ; canceler ;
          peer ; hash ; header ; operations }) ->
     let bv = Worker.state w in
-    let net_state = Distributed_db.net_state net_db in
-    State.Block.read_opt net_state hash >>= function
+    let chain_state = Distributed_db.chain_state chain_db in
+    State.Block.read_opt chain_state hash >>= function
     | Some block ->
         debug w "previously validated block %a (after pipe)"
           Block_hash.pp_short hash ;
@@ -231,26 +231,26 @@ let on_request
           block ;
         return (Ok block)
     | None ->
-        State.Block.read_invalid net_state hash >>= function
+        State.Block.read_invalid chain_state hash >>= function
         | Some { errors } ->
             return (Error errors)
         | None ->
             begin
               debug w "validating block %a" Block_hash.pp_short hash ;
               State.Block.read
-                net_state header.shell.predecessor >>=? fun pred ->
+                chain_state header.shell.predecessor >>=? fun pred ->
               get_proto pred hash >>=? fun proto ->
               (* TODO also protect with [Worker.canceler w]. *)
               protect ?canceler begin fun () ->
                 apply_block
-                  (Distributed_db.net_state net_db)
+                  (Distributed_db.chain_state chain_db)
                   pred proto hash header operations
               end
             end >>= function
             | Ok result -> begin
                 Worker.protect w begin fun () ->
                   Distributed_db.commit_block
-                    net_db hash header operations result
+                    chain_db hash header operations result
                 end >>=? function
                 | None ->
                     assert false (* should not happen *)
@@ -269,7 +269,7 @@ let on_request
             | Error errors ->
                 Worker.protect w begin fun () ->
                   Distributed_db.commit_invalid_block
-                    net_db hash header errors
+                    chain_db hash header errors
                 end >>=? fun commited ->
                 assert commited ;
                 return (Error errors)
@@ -318,10 +318,10 @@ let shutdown = Worker.shutdown
 
 let validate w
     ?canceler ?peer ?(notify_new_block = fun _ -> ())
-    net_db hash (header : Block_header.t) operations =
+    chain_db hash (header : Block_header.t) operations =
   let bv = Worker.state w in
-  let net_state = Distributed_db.net_state net_db in
-  State.Block.read_opt net_state hash >>= function
+  let chain_state = Distributed_db.chain_state chain_db in
+  State.Block.read_opt chain_state hash >>= function
   | Some block ->
       debug w "previously validated block %a (before pipe)"
         Block_hash.pp_short hash ;
@@ -346,10 +346,10 @@ let validate w
             expected = header.shell.operations_hash ;
             found = computed_hash ;
           }) >>=? fun () ->
-      check_net_liveness net_db hash header >>=? fun () ->
+      check_chain_liveness chain_db hash header >>=? fun () ->
       Worker.push_request_and_wait w
         (Request_validation
-           { net_db ; notify_new_block ; canceler ;
+           { chain_db ; notify_new_block ; canceler ;
              peer ; hash ; header ; operations }) >>=? fun result ->
       Lwt.return result
 
diff --git a/src/lib_shell/block_validator.mli b/src/lib_shell/block_validator.mli
index 58575d068..59c2dc8a1 100644
--- a/src/lib_shell/block_validator.mli
+++ b/src/lib_shell/block_validator.mli
@@ -24,7 +24,7 @@ val validate:
   ?canceler:Lwt_canceler.t ->
   ?peer:P2p_peer.Id.t ->
   ?notify_new_block:(State.Block.t -> unit) ->
-  Distributed_db.net_db ->
+  Distributed_db.chain_db ->
   Block_hash.t -> Block_header.t -> Operation.t list list ->
   State.Block.t tzresult Lwt.t
 
diff --git a/src/lib_shell/bootstrap_pipeline.ml b/src/lib_shell/bootstrap_pipeline.ml
index 891ff8672..f935ad87a 100644
--- a/src/lib_shell/bootstrap_pipeline.ml
+++ b/src/lib_shell/bootstrap_pipeline.ml
@@ -19,7 +19,7 @@ type t = {
   mutable operations_fetch_worker: unit Lwt.t ;
   mutable validation_worker: unit Lwt.t ;
   peer_id: P2p_peer.Id.t ;
-  net_db: Distributed_db.net_db ;
+  chain_db: Distributed_db.chain_db ;
   locator: Block_locator.t ;
   block_validator: Block_validator.t ;
   notify_new_block: State.Block.t -> unit ;
@@ -58,7 +58,7 @@ let fetch_step pipeline (step : Block_locator_iterator.step)  =
       protect ~canceler:pipeline.canceler begin fun () ->
         Distributed_db.Block_header.fetch
           ~timeout:pipeline.block_header_timeout
-          pipeline.net_db ~peer:pipeline.peer_id
+          pipeline.chain_db ~peer:pipeline.peer_id
           hash ()
       end >>=? fun header ->
       lwt_debug "fetched block header %a from peer %a."
@@ -116,7 +116,7 @@ let rec operations_fetch_worker_loop pipeline =
          protect ~canceler:pipeline.canceler begin fun () ->
            Distributed_db.Operations.fetch
              ~timeout:pipeline.block_operations_timeout
-             pipeline.net_db ~peer:pipeline.peer_id
+             pipeline.chain_db ~peer:pipeline.peer_id
              (hash, i) header.shell.operations_hash
          end)
       (0 -- (header.shell.validation_passes - 1)) >>=? fun operations ->
@@ -160,7 +160,7 @@ let rec validation_worker_loop pipeline =
         ~canceler:pipeline.canceler
         ~notify_new_block:pipeline.notify_new_block
         pipeline.block_validator
-        pipeline.net_db hash header operations
+        pipeline.chain_db hash header operations
     end >>=? fun _block ->
     lwt_log_info "validated block %a from peer %a."
       Block_hash.pp_short hash
@@ -186,7 +186,7 @@ let rec validation_worker_loop pipeline =
 let create
     ?(notify_new_block = fun _ -> ())
     ~block_header_timeout ~block_operations_timeout
-    block_validator peer_id net_db locator =
+    block_validator peer_id chain_db locator =
   let canceler = Lwt_canceler.create () in
   let fetched_headers =
     Lwt_pipe.create ~size:(50, fun _ -> 1) () in
@@ -199,7 +199,7 @@ let create
     operations_fetch_worker = Lwt.return_unit ;
     validation_worker = Lwt.return_unit ;
     notify_new_block ;
-    peer_id ; net_db ; locator ;
+    peer_id ; chain_db ; locator ;
     block_validator ;
     fetched_headers ; fetched_blocks ;
     errors = [] ;
diff --git a/src/lib_shell/bootstrap_pipeline.mli b/src/lib_shell/bootstrap_pipeline.mli
index cedbceba7..59f0a5b87 100644
--- a/src/lib_shell/bootstrap_pipeline.mli
+++ b/src/lib_shell/bootstrap_pipeline.mli
@@ -16,7 +16,7 @@ val create:
   block_header_timeout:float ->
   block_operations_timeout: float ->
   Block_validator.t ->
-  P2p_peer.Id.t -> Distributed_db.net_db ->
+  P2p_peer.Id.t -> Distributed_db.chain_db ->
   Block_locator.t -> t
 
 val wait: t -> unit tzresult Lwt.t
diff --git a/src/lib_shell/chain.ml b/src/lib_shell/chain.ml
index 7187a44f4..cfe2addf4 100644
--- a/src/lib_shell/chain.ml
+++ b/src/lib_shell/chain.ml
@@ -8,76 +8,76 @@
 (**************************************************************************)
 
 open Logging.Node.State
-open State
 
 let mempool_encoding = Mempool.encoding
 
-let genesis net_state =
-  let genesis = Net.genesis net_state in
-  Block.read_exn net_state genesis.block
+let genesis chain_state =
+  let genesis = State.Chain.genesis chain_state in
+  State.Block.read_exn chain_state genesis.block
 
-let known_heads net_state =
-  read_chain_store net_state begin fun chain_store _data ->
-    Store.Chain.Known_heads.elements chain_store
+let known_heads chain_state =
+  State.read_chain_data chain_state begin fun chain_store _data ->
+    Store.Chain_data.Known_heads.elements chain_store
   end >>= fun hashes ->
-  Lwt_list.map_p (Block.read_exn net_state) hashes
+  Lwt_list.map_p (State.Block.read_exn chain_state) hashes
 
-let head net_state =
-  read_chain_store net_state begin fun _chain_store data ->
+let head chain_state =
+  State.read_chain_data chain_state begin fun _chain_store data ->
     Lwt.return data.current_head
   end
 
-let mem net_state hash =
-  read_chain_store net_state begin fun chain_store data ->
-    if Block_hash.equal (Block.hash data.current_head) hash then
+let mem chain_state hash =
+  State.read_chain_data chain_state begin fun chain_store data ->
+    if Block_hash.equal (State.Block.hash data.current_head) hash then
       Lwt.return true
     else
-      Store.Chain.In_chain.known (chain_store, hash)
+      Store.Chain_data.In_main_branch.known (chain_store, hash)
   end
 
 type data = State.chain_data = {
-  current_head: Block.t ;
+  current_head: State.Block.t ;
   current_mempool: Mempool.t ;
   live_blocks: Block_hash.Set.t ;
   live_operations: Operation_hash.Set.t ;
   locator: Block_locator.t Lwt.t lazy_t ;
 }
 
-let data net_state =
-  read_chain_store net_state begin fun _chain_store data ->
+let data chain_state =
+  State.read_chain_data chain_state begin fun _chain_store data ->
     Lwt.return data
   end
 
-let locator net_state =
-  data net_state >>= begin fun data ->
+let locator chain_state =
+  data chain_state >>= begin fun data ->
     Lazy.force data.locator
   end
 
-let locked_set_head net_state chain_store data block =
+let locked_set_head chain_state chain_store data block =
   let rec pop_blocks ancestor block =
-    let hash = Block.hash block in
+    let hash = State.Block.hash block in
     if Block_hash.equal hash ancestor then
       Lwt.return_unit
     else
       lwt_debug "pop_block %a" Block_hash.pp_short hash >>= fun () ->
-      Store.Chain.In_chain.remove (chain_store, hash) >>= fun () ->
-      Block.predecessor block >>= function
+      Store.Chain_data.In_main_branch.remove (chain_store, hash) >>= fun () ->
+      State.Block.predecessor block >>= function
       | Some predecessor ->
           pop_blocks ancestor predecessor
       | None -> assert false (* Cannot pop the genesis... *)
   in
   let push_block pred_hash block =
-    let hash = Block.hash block in
+    let hash = State.Block.hash block in
     lwt_debug "push_block %a" Block_hash.pp_short hash >>= fun () ->
-    Store.Chain.In_chain.store (chain_store, pred_hash) hash >>= fun () ->
+    Store.Chain_data.In_main_branch.store
+      (chain_store, pred_hash) hash >>= fun () ->
     Lwt.return hash
   in
   Chain_traversal.new_blocks
     ~from_block:data.current_head ~to_block:block >>= fun (ancestor, path) ->
-  let ancestor = Block.hash ancestor in
+  let ancestor = State.Block.hash ancestor in
   pop_blocks ancestor data.current_head >>= fun () ->
   Lwt_list.fold_left_s push_block ancestor path >>= fun _ ->
-  Store.Chain.Current_head.store chain_store (Block.hash block) >>= fun () ->
+  Store.Chain_data.Current_head.store chain_store (State.Block.hash block) >>= fun () ->
   (* TODO more optimized updated of live_{blocks/operations} when the
      new head is a direct successor of the current head...
      Make sure to do the live blocks computation in `init_head`
@@ -89,27 +89,27 @@ let locked_set_head net_state chain_store data block =
                current_mempool = Mempool.empty ;
                live_blocks ;
                live_operations ;
-               locator = lazy (State.compute_locator net_state block) ;
+               locator = lazy (State.compute_locator chain_state block) ;
              }
 
-let set_head net_state block =
-  update_chain_store net_state begin fun chain_store data ->
-    locked_set_head net_state chain_store data block >>= fun new_chain_data ->
+let set_head chain_state block =
+  State.update_chain_data chain_state begin fun chain_store data ->
+    locked_set_head chain_state chain_store data block >>= fun new_chain_data ->
     Lwt.return (Some new_chain_data,
                 data.current_head)
   end
 
-let test_and_set_head net_state ~old block =
-  update_chain_store net_state begin fun chain_store data ->
-    if not (Block.equal data.current_head old) then
+let test_and_set_head chain_state ~old block =
+  State.update_chain_data chain_state begin fun chain_store data ->
+    if not (State.Block.equal data.current_head old) then
       Lwt.return (None, false)
     else
-      locked_set_head net_state chain_store data block >>= fun new_chain_data ->
+      locked_set_head chain_state chain_store data block >>= fun new_chain_data ->
       Lwt.return (Some new_chain_data, true)
   end
 
-let init_head net_state =
-  head net_state >>= fun block ->
-  set_head net_state block >>= fun _ ->
+let init_head chain_state =
+  head chain_state >>= fun block ->
+  set_head chain_state block >>= fun _ ->
   Lwt.return_unit
 
diff --git a/src/lib_shell/chain.mli b/src/lib_shell/chain.mli
index 792abc51b..8da902444 100644
--- a/src/lib_shell/chain.mli
+++ b/src/lib_shell/chain.mli
@@ -9,19 +9,17 @@
 
 (** Tezos Shell Module - Manging the current head. *)
 
-open State
-
-(** The genesis block of the network's blockchain. On a test network,
+(** The genesis block of the chain. On a test chain,
     the test protocol has been promoted as "main" protocol. *)
-val genesis: Net.t -> Block.t Lwt.t
+val genesis: State.Chain.t -> State.Block.t Lwt.t
 
-(** The current head of the network's blockchain. *)
-val head: Net.t -> Block.t Lwt.t
-val locator: Net.t -> Block_locator.t Lwt.t
+(** The current head of the chain. *)
+val head: State.Chain.t -> State.Block.t Lwt.t
+val locator: State.Chain.t -> Block_locator.t Lwt.t
 
 (** All the available chain data. *)
 type data = {
-  current_head: Block.t ;
+  current_head: State.Block.t ;
   current_mempool: Mempool.t ;
   live_blocks: Block_hash.Set.t ;
   live_operations: Operation_hash.Set.t ;
@@ -29,25 +27,25 @@ type data = {
 }
 
 (** Reading atomically all the chain data. *)
-val data: Net.t -> data Lwt.t
+val data: State.Chain.t -> data Lwt.t
 
 
 (** The current head and all the known (valid) alternate heads. *)
-val known_heads: Net.t -> Block.t list Lwt.t
+val known_heads: State.Chain.t -> State.Block.t list Lwt.t
 
-(** Test whether a block belongs to the current mainnet. *)
-val mem: Net.t -> Block_hash.t -> bool Lwt.t
+(** Test whether a block belongs to the current mainchain. *)
+val mem: State.Chain.t -> Block_hash.t -> bool Lwt.t
 
-(** Record a block as the current head of the network's blockchain.
+(** Record a block as the current head of the chain.
     It returns the previous head. *)
-val set_head: Net.t -> Block.t -> Block.t Lwt.t
+val set_head: State.Chain.t -> State.Block.t -> State.Block.t Lwt.t
 
-(** Atomically change the current head of the network's blockchain.
+(** Atomically change the current head of the chain.
     This returns [true] whenever the change succeeded, or [false]
     when the current head os not equal to the [old] argument. *)
 val test_and_set_head:
-  Net.t -> old:Block.t -> Block.t -> bool Lwt.t
+  State.Chain.t -> old:State.Block.t -> State.Block.t -> bool Lwt.t
 
 (** Restores the data about the current head at startup
     (recomputes the sets of live blocks and operations). *)
-val init_head: Net.t -> unit Lwt.t
+val init_head: State.Chain.t -> unit Lwt.t
diff --git a/src/lib_shell/chain_traversal.ml b/src/lib_shell/chain_traversal.ml
index 75c35d24f..46a049337 100644
--- a/src/lib_shell/chain_traversal.ml
+++ b/src/lib_shell/chain_traversal.ml
@@ -10,7 +10,7 @@
 open State
 
 let path (b1: Block.t) (b2: Block.t) =
-  if not (Net_id.equal (Block.net_id b1) (Block.net_id b2)) then
+  if not (Chain_id.equal (Block.chain_id b1) (Block.chain_id b2)) then
     invalid_arg "Chain_traversal.path" ;
   let rec loop acc current =
     if Block.equal b1 current then
@@ -22,7 +22,7 @@ let path (b1: Block.t) (b2: Block.t) =
   loop [] b2
 
 let common_ancestor (b1: Block.t) (b2: Block.t) =
-  if not ( Net_id.equal (Block.net_id b1) (Block.net_id b2)) then
+  if not ( Chain_id.equal (Block.chain_id b1) (Block.chain_id b2)) then
     invalid_arg "Chain_traversal.path" ;
   let rec loop (b1: Block.t) (b2: Block.t) =
     if Block.equal b1 b2 then
@@ -103,8 +103,8 @@ let iter_predecessors ?max ?min_fitness ?min_date heads ~f =
   match heads with
   | [] -> Lwt.return_unit
   | b :: _ ->
-      let net_id = Block.net_id b in
-      if not (List.for_all (fun b -> Net_id.equal net_id (Block.net_id b)) heads) then
+      let chain_id = Block.chain_id b in
+      if not (List.for_all (fun b -> Chain_id.equal chain_id (Block.chain_id b)) heads) then
         invalid_arg "State.Helpers.iter_predecessors" ;
       iter_predecessors ?max ?min_fitness ?min_date heads ~f
 
diff --git a/src/lib_shell/chain_traversal.mli b/src/lib_shell/chain_traversal.mli
index f9f366d5c..d0fa1e971 100644
--- a/src/lib_shell/chain_traversal.mli
+++ b/src/lib_shell/chain_traversal.mli
@@ -43,7 +43,7 @@ val new_blocks:
     and [to_block] and where [path] is the chain from [ancestor]
     (excluded) to [to_block] (included).  The function raises an
     exception when the two provided blocks do not belong the the same
-    [net].  *)
+    [chain].  *)
 
 val live_blocks:
   Block.t -> int -> (Block_hash.Set.t * Operation_hash.Set.t) Lwt.t
diff --git a/src/lib_shell/net_validator.ml b/src/lib_shell/chain_validator.ml
similarity index 81%
rename from src/lib_shell/net_validator.ml
rename to src/lib_shell/chain_validator.ml
index 5a80fd04a..8abe16788 100644
--- a/src/lib_shell/net_validator.ml
+++ b/src/lib_shell/chain_validator.ml
@@ -7,13 +7,13 @@
 (*                                                                        *)
 (**************************************************************************)
 
-open Net_validator_worker_state
+open Chain_validator_worker_state
 
 module Name = struct
-  type t = Net_id.t
-  let encoding = Net_id.encoding
-  let base = [ "net_validator" ]
-  let pp = Net_id.pp_short
+  type t = Chain_id.t
+  let encoding = Chain_id.encoding
+  let base = [ "chain_validator" ]
+  let pp = Chain_id.pp_short
 end
 
 module Request = struct
@@ -34,8 +34,8 @@ module Types = struct
   type parameters = {
     parent: Name.t option ;
     db: Distributed_db.t ;
-    net_state: State.Net.t ;
-    net_db: Distributed_db.net_db ;
+    chain_state: State.Chain.t ;
+    chain_db: Distributed_db.chain_db ;
     block_validator: Block_validator.t ;
     global_valid_block_input: State.Block.t Lwt_watcher.input ;
 
@@ -96,7 +96,7 @@ let notify_new_block w block =
   Lwt_watcher.notify nv.parameters.global_valid_block_input block ;
   Worker.push_request_now w (Validated block)
 
-let may_toggle_bootstrapped_network w =
+let may_toggle_bootstrapped_chain w =
   let nv = Worker.state w in
   if not nv.bootstrapped &&
      P2p_peer.Table.length nv.bootstrapped_peers >= nv.parameters.limits.bootstrap_threshold
@@ -114,7 +114,7 @@ let may_activate_peer_validator w peer_id =
         ~notify_new_block:(notify_new_block w)
         ~notify_bootstrapped: begin fun () ->
           P2p_peer.Table.add nv.bootstrapped_peers peer_id () ;
-          may_toggle_bootstrapped_network w
+          may_toggle_bootstrapped_chain w
         end
         ~notify_termination: begin fun _pv ->
           P2p_peer.Table.remove nv.active_peers peer_id ;
@@ -122,36 +122,36 @@ let may_activate_peer_validator w peer_id =
         end
         nv.parameters.peer_validator_limits
         nv.parameters.block_validator
-        nv.parameters.net_db
+        nv.parameters.chain_db
         peer_id in
     P2p_peer.Table.add nv.active_peers peer_id pv ;
     pv
 
-let may_switch_test_network w spawn_child block =
+let may_switch_test_chain w spawn_child block =
   let nv = Worker.state w in
   let create_child genesis protocol expiration =
-    if State.Net.allow_forked_network nv.parameters.net_state then begin
+    if State.Chain.allow_forked_chain nv.parameters.chain_state then begin
       shutdown_child nv >>= fun () ->
       begin
-        let net_id = Net_id.of_block_hash (State.Block.hash genesis) in
-        State.Net.get
-          (State.Net.global_state nv.parameters.net_state) net_id >>= function
-        | Ok net_state -> return net_state
+        let chain_id = Chain_id.of_block_hash (State.Block.hash genesis) in
+        State.Chain.get
+          (State.Chain.global_state nv.parameters.chain_state) chain_id >>= function
+        | Ok chain_state -> return chain_state
         | Error _ ->
-            State.fork_testnet
-              genesis protocol expiration >>=? fun net_state ->
-            Chain.head net_state >>= fun new_genesis_block ->
+            State.fork_testchain
+              genesis protocol expiration >>=? fun chain_state ->
+            Chain.head chain_state >>= fun new_genesis_block ->
             Lwt_watcher.notify nv.parameters.global_valid_block_input new_genesis_block ;
             Lwt_watcher.notify nv.valid_block_input new_genesis_block ;
-            return net_state
-      end >>=? fun net_state ->
+            return chain_state
+      end >>=? fun chain_state ->
       spawn_child
-        ~parent:(State.Net.id net_state)
+        ~parent:(State.Chain.id chain_state)
         nv.parameters.peer_validator_limits
         nv.parameters.prevalidator_limits
         nv.parameters.block_validator
         nv.parameters.global_valid_block_input
-        nv.parameters.db net_state
+        nv.parameters.db chain_state
         nv.parameters.limits (* TODO: different limits main/test ? *) >>= fun child ->
       nv.child <- Some child ;
       return ()
@@ -166,9 +166,9 @@ let may_switch_test_network w spawn_child block =
       | None -> false
       | Some (child , _) ->
           Block_hash.equal
-            (State.Net.genesis child.parameters.net_state).block
+            (State.Chain.genesis child.parameters.chain_state).block
             genesis in
-    State.Block.read nv.parameters.net_state genesis >>=? fun genesis ->
+    State.Block.read nv.parameters.chain_state genesis >>=? fun genesis ->
     begin
       match nv.parameters.max_child_ttl with
       | None -> Lwt.return expiration
@@ -187,7 +187,7 @@ let may_switch_test_network w spawn_child block =
 
   begin
     let block_header = State.Block.header block in
-    State.Block.test_network block >>= function
+    State.Block.test_chain block >>= function
     | Not_running -> shutdown_child nv >>= return
     | Running { genesis ; protocol ; expiration } ->
         check_child genesis protocol expiration
@@ -197,7 +197,7 @@ let may_switch_test_network w spawn_child block =
   end >>= function
   | Ok () -> Lwt.return_unit
   | Error err ->
-      Worker.record_event w (Could_not_switch_testnet err) ;
+      Worker.record_event w (Could_not_switch_testchain err) ;
       Lwt.return_unit
 
 let broadcast_head w ~previous block =
@@ -213,20 +213,20 @@ let broadcast_head w ~previous block =
     end >>= fun successor ->
     if successor then begin
       Distributed_db.Advertise.current_head
-        nv.parameters.net_db block ;
+        nv.parameters.chain_db block ;
       Lwt.return_unit
     end else begin
-      let net_state = Distributed_db.net_state nv.parameters.net_db in
-      Chain.locator net_state >>= fun locator ->
+      let chain_state = Distributed_db.chain_state nv.parameters.chain_db in
+      Chain.locator chain_state >>= fun locator ->
       Distributed_db.Advertise.current_branch
-        nv.parameters.net_db locator
+        nv.parameters.chain_db locator
     end
   end
 
 let on_request (type a) w spawn_child (req : a Request.t) : a tzresult Lwt.t =
   let Request.Validated block = req in
   let nv = Worker.state w in
-  Chain.head nv.parameters.net_state >>= fun head ->
+  Chain.head nv.parameters.chain_state >>= fun head ->
   let head_header = State.Block.header head
   and head_hash = State.Block.hash head
   and block_header = State.Block.header block
@@ -236,10 +236,10 @@ let on_request (type a) w spawn_child (req : a Request.t) : a tzresult Lwt.t =
   then
     return Event.Ignored_head
   else begin
-    Chain.set_head nv.parameters.net_state block >>= fun previous ->
+    Chain.set_head nv.parameters.chain_state block >>= fun previous ->
     broadcast_head w ~previous block >>= fun () ->
     Prevalidator.flush nv.prevalidator block_hash >>=? fun () ->
-    may_switch_test_network w spawn_child block >>= fun () ->
+    may_switch_test_chain w spawn_child block >>= fun () ->
     Lwt_watcher.notify nv.new_head_input block ;
     if Block_hash.equal head_hash block_header.shell.predecessor then
       return Event.Head_incrememt
@@ -256,7 +256,7 @@ let on_completion (type a) w  (req : a Request.t) (update : a) request_status =
 
 let on_close w =
   let nv = Worker.state w in
-  Distributed_db.deactivate nv.parameters.net_db >>= fun () ->
+  Distributed_db.deactivate nv.parameters.chain_db >>= fun () ->
   Lwt.join
     (Prevalidator.shutdown nv.prevalidator ::
      Lwt_utils.may ~f:(fun (_, shutdown) -> shutdown ()) nv.child ::
@@ -266,9 +266,9 @@ let on_close w =
   Lwt.return_unit
 
 let on_launch w _ parameters =
-  Chain.init_head parameters.net_state >>= fun () ->
+  Chain.init_head parameters.chain_state >>= fun () ->
   Prevalidator.create
-    parameters.prevalidator_limits parameters.net_db >>= fun prevalidator ->
+    parameters.prevalidator_limits parameters.chain_db >>= fun prevalidator ->
   let valid_block_input = Lwt_watcher.create_input () in
   let new_head_input = Lwt_watcher.create_input () in
   let bootstrapped_waiter, bootstrapped_wakener = Lwt.wait () in
@@ -286,7 +286,7 @@ let on_launch w _ parameters =
       child = None ;
       prevalidator } in
   if nv.bootstrapped then Lwt.wakeup_later bootstrapped_wakener () ;
-  Distributed_db.set_callback parameters.net_db {
+  Distributed_db.set_callback parameters.chain_db {
     notify_branch = begin fun peer_id locator ->
       Lwt.async begin fun () ->
         may_activate_peer_validator w peer_id >>= fun pv ->
@@ -316,7 +316,7 @@ let on_launch w _ parameters =
 let rec create
     ?max_child_ttl ?parent
     peer_validator_limits prevalidator_limits block_validator
-    global_valid_block_input db net_state limits =
+    global_valid_block_input db chain_state limits =
   let spawn_child ~parent pvl pl bl gvbi db n l =
     create ~parent pvl pl bl gvbi db n l >>= fun w ->
     Lwt.return (Worker.state w, (fun () -> Worker.shutdown w)) in
@@ -337,12 +337,12 @@ let rec create
       block_validator ;
       global_valid_block_input ;
       db ;
-      net_db = Distributed_db.activate db net_state ;
-      net_state ;
+      chain_db = Distributed_db.activate db chain_state ;
+      chain_state ;
       limits } in
   Worker.launch table
     prevalidator_limits.worker_limits
-    (State.Net.id net_state)
+    (State.Chain.id chain_state)
     parameters
     (module Handlers)
 
@@ -358,33 +358,33 @@ let create
     peer_validator_limits prevalidator_limits
     block_validator global_valid_block_input global_db state limits
 
-let net_id w =
-  let { parameters = { net_state } } = Worker.state w in
-  State.Net.id net_state
+let chain_id w =
+  let { parameters = { chain_state } } = Worker.state w in
+  State.Chain.id chain_state
 
-let net_state w =
-  let { parameters = { net_state } } = Worker.state w in
-  net_state
+let chain_state w =
+  let { parameters = { chain_state } } = Worker.state w in
+  chain_state
 
 let prevalidator w =
   let { prevalidator } = Worker.state w in
   prevalidator
 
-let net_db w =
-  let { parameters = { net_db } } = Worker.state w in
-  net_db
+let chain_db w =
+  let { parameters = { chain_db } } = Worker.state w in
+  chain_db
 
 let child w =
   match (Worker.state w).child with
   | None -> None
-  | Some ({ parameters = { net_state } }, _) ->
-      try Some (List.assoc (State.Net.id net_state) (Worker.list table))
+  | Some ({ parameters = { chain_state } }, _) ->
+      try Some (List.assoc (State.Chain.id chain_state) (Worker.list table))
       with Not_found -> None
 
 let validate_block w ?(force = false) hash block operations =
   let nv = Worker.state w in
   assert (Block_hash.equal hash (Block_header.hash block)) ;
-  Chain.head nv.parameters.net_state >>= fun head ->
+  Chain.head nv.parameters.chain_state >>= fun head ->
   let head = State.Block.header head in
   if
     force || Fitness.(head.shell.fitness <= block.shell.fitness)
@@ -393,7 +393,7 @@ let validate_block w ?(force = false) hash block operations =
       ~canceler:(Worker.canceler w)
       ~notify_new_block:(notify_new_block w)
       nv.parameters.block_validator
-      nv.parameters.net_db
+      nv.parameters.chain_db
       hash block operations
   else
     failwith "Fitness too low"
diff --git a/src/lib_shell/net_validator.mli b/src/lib_shell/chain_validator.mli
similarity index 75%
rename from src/lib_shell/net_validator.mli
rename to src/lib_shell/chain_validator.mli
index ac5a36668..e64d48ca8 100644
--- a/src/lib_shell/net_validator.mli
+++ b/src/lib_shell/chain_validator.mli
@@ -21,16 +21,16 @@ val create:
   Block_validator.t ->
   State.Block.t Lwt_watcher.input ->
   Distributed_db.t ->
-  State.Net.t ->
+  State.Chain.t ->
   limits ->
   t Lwt.t
 
 val bootstrapped: t -> unit Lwt.t
 
-val net_id: t -> Net_id.t
-val net_state: t -> State.Net.t
+val chain_id: t -> Chain_id.t
+val chain_state: t -> State.Chain.t
 val prevalidator: t -> Prevalidator.t
-val net_db: t -> Distributed_db.net_db
+val chain_db: t -> Distributed_db.chain_db
 val child: t -> t option
 
 val validate_block:
@@ -44,9 +44,9 @@ val shutdown: t -> unit Lwt.t
 val valid_block_watcher: t -> State.Block.t Lwt_stream.t * Lwt_watcher.stopper
 val new_head_watcher: t -> State.Block.t Lwt_stream.t * Lwt_watcher.stopper
 
-val running_workers: unit -> (Net_id.t * t) list
+val running_workers: unit -> (Chain_id.t * t) list
 val status: t -> Worker_types.worker_status
 
-val pending_requests : t -> (Time.t * Net_validator_worker_state.Request.view) list
-val current_request : t -> (Time.t * Time.t * Net_validator_worker_state.Request.view) option
-val last_events : t -> (Lwt_log_core.level * Net_validator_worker_state.Event.t list) list
+val pending_requests : t -> (Time.t * Chain_validator_worker_state.Request.view) list
+val current_request : t -> (Time.t * Time.t * Chain_validator_worker_state.Request.view) option
+val last_events : t -> (Lwt_log_core.level * Chain_validator_worker_state.Event.t list) list
diff --git a/src/lib_shell/distributed_db.ml b/src/lib_shell/distributed_db.ml
index 921b684dc..28768da15 100644
--- a/src/lib_shell/distributed_db.ml
+++ b/src/lib_shell/distributed_db.ml
@@ -68,7 +68,7 @@ module Make_raw
 end
 
 module Fake_operation_storage = struct
-  type store = State.Net.t
+  type store = State.Chain.t
   type value = Operation.t
   let known _ _ = Lwt.return_false
   let read _ _ = Lwt.return (Error_monad.error_exn Not_found)
@@ -92,17 +92,17 @@ module Raw_operation =
     end)
 
 module Block_header_storage = struct
-  type store = State.Net.t
+  type store = State.Chain.t
   type value = Block_header.t
   let known = State.Block.known_valid
-  let read net_state h =
-    State.Block.read net_state h >>=? fun b ->
+  let read chain_state h =
+    State.Block.read chain_state h >>=? fun b ->
     return (State.Block.header b)
-  let read_opt net_state h =
-    State.Block.read_opt net_state h >>= fun b ->
+  let read_opt chain_state h =
+    State.Block.read_opt chain_state h >>= fun b ->
     Lwt.return (Option.map ~f:State.Block.header b)
-  let read_exn net_state h =
-    State.Block.read_exn net_state h >>= fun b ->
+  let read_exn chain_state h =
+    State.Block.read_exn chain_state h >>= fun b ->
     Lwt.return (State.Block.header b)
 end
 
@@ -122,21 +122,21 @@ module Raw_block_header =
     end)
 
 module Operation_hashes_storage = struct
-  type store = State.Net.t
+  type store = State.Chain.t
   type value = Operation_hash.t list
-  let known net_state (h, _) = State.Block.known_valid net_state h
-  let read net_state (h, i) =
-    State.Block.read net_state h >>=? fun b ->
+  let known chain_state (h, _) = State.Block.known_valid chain_state h
+  let read chain_state (h, i) =
+    State.Block.read chain_state h >>=? fun b ->
     State.Block.operation_hashes b i >>= fun (ops, _) ->
     return ops
-  let read_opt net_state (h, i) =
-    State.Block.read_opt net_state h >>= function
+  let read_opt chain_state (h, i) =
+    State.Block.read_opt chain_state h >>= function
     | None -> Lwt.return_none
     | Some b ->
         State.Block.operation_hashes b i >>= fun (ops, _) ->
         Lwt.return (Some ops)
-  let read_exn net_state (h, i) =
-    State.Block.read_exn net_state h >>= fun b ->
+  let read_exn chain_state (h, i) =
+    State.Block.read_exn chain_state h >>= fun b ->
     State.Block.operation_hashes b i >>= fun (ops, _) ->
     Lwt.return ops
 end
@@ -199,21 +199,21 @@ module Raw_operation_hashes = struct
 end
 
 module Operations_storage = struct
-  type store = State.Net.t
+  type store = State.Chain.t
   type value = Operation.t list
-  let known net_state (h, _) = State.Block.known_valid net_state h
-  let read net_state (h, i) =
-    State.Block.read net_state h >>=? fun b ->
+  let known chain_state (h, _) = State.Block.known_valid chain_state h
+  let read chain_state (h, i) =
+    State.Block.read chain_state h >>=? fun b ->
     State.Block.operations b i >>= fun (ops, _) ->
     return ops
-  let read_opt net_state (h, i) =
-    State.Block.read_opt net_state h >>= function
+  let read_opt chain_state (h, i) =
+    State.Block.read_opt chain_state h >>= function
     | None -> Lwt.return_none
     | Some b ->
         State.Block.operations b i >>= fun (ops, _) ->
         Lwt.return (Some ops)
-  let read_exn net_state (h, i) =
-    State.Block.read_exn net_state h >>= fun b ->
+  let read_exn chain_state (h, i) =
+    State.Block.read_exn chain_state h >>= fun b ->
     State.Block.operations b i >>= fun (ops, _) ->
     Lwt.return ops
 end
@@ -302,14 +302,14 @@ type db = {
   p2p: p2p ;
   p2p_readers: p2p_reader P2p_peer.Table.t ;
   disk: State.t ;
-  active_nets: net_db Net_id.Table.t ;
+  active_chains: chain_db Chain_id.Table.t ;
   protocol_db: Raw_protocol.t ;
   block_input: (Block_hash.t * Block_header.t) Lwt_watcher.input ;
   operation_input: (Operation_hash.t * Operation.t) Lwt_watcher.input ;
 }
 
-and net_db = {
-  net_state: State.Net.t ;
+and chain_db = {
+  chain_state: State.Chain.t ;
   global_db: db ;
   operation_db: Raw_operation.t ;
   block_header_db: Raw_block_header.t ;
@@ -323,7 +323,7 @@ and net_db = {
 and p2p_reader = {
   gid: P2p_peer.Id.t ;
   conn: connection ;
-  peer_active_nets: net_db Net_id.Table.t ;
+  peer_active_chains: chain_db Chain_id.Table.t ;
   canceler: Lwt_canceler.t ;
   mutable worker: unit Lwt.t ;
 }
@@ -337,116 +337,116 @@ let noop_callback = {
 type t = db
 
 let state { disk } = disk
-let net_state { net_state } = net_state
+let chain_state { chain_state } = chain_state
 let db { global_db } = global_db
 
 let read_block_header { disk } h =
   State.read_block disk h >>= function
   | Some b ->
-      Lwt.return_some (State.Block.net_id b, State.Block.header b)
+      Lwt.return_some (State.Block.chain_id b, State.Block.header b)
   | None ->
       Lwt.return_none
 
-let find_pending_block_header { peer_active_nets } h  =
-  Net_id.Table.fold
-    (fun _net_id net_db acc ->
+let find_pending_block_header { peer_active_chains } h  =
+  Chain_id.Table.fold
+    (fun _chain_id chain_db acc ->
        match acc with
        | Some _ -> acc
        | None when Raw_block_header.Table.pending
-             net_db.block_header_db.table h ->
-           Some net_db
+             chain_db.block_header_db.table h ->
+           Some chain_db
        | None -> None)
-    peer_active_nets
+    peer_active_chains
     None
 
-let find_pending_operations { peer_active_nets } h i =
-  Net_id.Table.fold
-    (fun _net_id net_db acc ->
+let find_pending_operations { peer_active_chains } h i =
+  Chain_id.Table.fold
+    (fun _chain_id chain_db acc ->
        match acc with
        | Some _ -> acc
        | None when Raw_operations.Table.pending
-             net_db.operations_db.table (h, i) ->
-           Some net_db
+             chain_db.operations_db.table (h, i) ->
+           Some chain_db
        | None -> None)
-    peer_active_nets
+    peer_active_chains
     None
 
-let find_pending_operation_hashes { peer_active_nets } h i =
-  Net_id.Table.fold
-    (fun _net_id net_db acc ->
+let find_pending_operation_hashes { peer_active_chains } h i =
+  Chain_id.Table.fold
+    (fun _chain_id chain_db acc ->
        match acc with
        | Some _ -> acc
        | None when Raw_operation_hashes.Table.pending
-             net_db.operation_hashes_db.table (h, i) ->
-           Some net_db
+             chain_db.operation_hashes_db.table (h, i) ->
+           Some chain_db
        | None -> None)
-    peer_active_nets
+    peer_active_chains
     None
 
-let find_pending_operation { peer_active_nets } h =
-  Net_id.Table.fold
-    (fun _net_id net_db acc ->
+let find_pending_operation { peer_active_chains } h =
+  Chain_id.Table.fold
+    (fun _chain_id chain_db acc ->
        match acc with
        | Some _ -> acc
        | None when Raw_operation.Table.pending
-             net_db.operation_db.table h ->
-           Some net_db
+             chain_db.operation_db.table h ->
+           Some chain_db
        | None -> None)
-    peer_active_nets
+    peer_active_chains
     None
 
-let read_operation { active_nets } h =
-  Net_id.Table.fold
-    (fun net_id net_db acc ->
+let read_operation { active_chains } h =
+  Chain_id.Table.fold
+    (fun chain_id chain_db acc ->
        acc >>= function
        | Some _ -> acc
        | None ->
            Raw_operation.Table.read_opt
-             net_db.operation_db.table h >>= function
+             chain_db.operation_db.table h >>= function
            | None -> Lwt.return_none
-           | Some bh -> Lwt.return_some (net_id, bh))
-    active_nets
+           | Some bh -> Lwt.return_some (chain_id, bh))
+    active_chains
     Lwt.return_none
 
 module P2p_reader = struct
 
-  let may_activate global_db state net_id f =
-    match Net_id.Table.find state.peer_active_nets net_id with
-    | net_db ->
-        f net_db
+  let may_activate global_db state chain_id f =
+    match Chain_id.Table.find state.peer_active_chains chain_id with
+    | chain_db ->
+        f chain_db
     | exception Not_found ->
-        match Net_id.Table.find global_db.active_nets net_id with
-        | net_db ->
-            net_db.active_peers :=
-              P2p_peer.Set.add state.gid !(net_db.active_peers) ;
-            P2p_peer.Table.add net_db.active_connections
+        match Chain_id.Table.find global_db.active_chains chain_id with
+        | chain_db ->
+            chain_db.active_peers :=
+              P2p_peer.Set.add state.gid !(chain_db.active_peers) ;
+            P2p_peer.Table.add chain_db.active_connections
               state.gid state ;
-            Net_id.Table.add state.peer_active_nets net_id net_db ;
-            f net_db
+            Chain_id.Table.add state.peer_active_chains chain_id chain_db ;
+            f chain_db
         | exception Not_found ->
             (* TODO  decrease peer score. *)
             Lwt.return_unit
 
-  let deactivate state net_db =
-    net_db.callback.disconnection state.gid ;
-    net_db.active_peers :=
-      P2p_peer.Set.remove state.gid !(net_db.active_peers) ;
-    P2p_peer.Table.remove net_db.active_connections state.gid
+  let deactivate state chain_db =
+    chain_db.callback.disconnection state.gid ;
+    chain_db.active_peers :=
+      P2p_peer.Set.remove state.gid !(chain_db.active_peers) ;
+    P2p_peer.Table.remove chain_db.active_connections state.gid
 
-  let may_handle state net_id f =
-    match Net_id.Table.find state.peer_active_nets net_id with
+  let may_handle state chain_id f =
+    match Chain_id.Table.find state.peer_active_chains chain_id with
     | exception Not_found ->
         (* TODO decrease peer score *)
         Lwt.return_unit
-    | net_db ->
-        f net_db
+    | chain_db ->
+        f chain_db
 
-  let may_handle_global global_db net_id f =
-    match Net_id.Table.find global_db.active_nets net_id with
+  let may_handle_global global_db chain_id f =
+    match Chain_id.Table.find global_db.active_chains chain_id with
     | exception Not_found ->
         Lwt.return_unit
-    | net_db ->
-        f net_db
+    | chain_db ->
+        f chain_db
 
   let handle_msg global_db state msg =
 
@@ -460,50 +460,50 @@ module P2p_reader = struct
 
     match msg with
 
-    | Get_current_branch net_id ->
-        may_handle_global global_db net_id @@ fun net_db ->
-        if not (Net_id.Table.mem state.peer_active_nets net_id) then
+    | Get_current_branch chain_id ->
+        may_handle_global global_db chain_id @@ fun chain_db ->
+        if not (Chain_id.Table.mem state.peer_active_chains chain_id) then
           ignore
           @@ P2p.try_send global_db.p2p state.conn
-          @@ Get_current_branch net_id ;
-        Chain.locator net_db.net_state >>= fun locator ->
+          @@ Get_current_branch chain_id ;
+        Chain.locator chain_db.chain_state >>= fun locator ->
         ignore
         @@ P2p.try_send global_db.p2p state.conn
-        @@ Current_branch (net_id, locator) ;
+        @@ Current_branch (chain_id, locator) ;
         Lwt.return_unit
 
-    | Current_branch (net_id, locator) ->
-        may_activate global_db state net_id @@ fun net_db ->
+    | Current_branch (chain_id, locator) ->
+        may_activate global_db state chain_id @@ fun chain_db ->
         let head, hist = (locator :> Block_header.t * Block_hash.t list) in
         Lwt_list.exists_p
-          (State.Block.known_invalid net_db.net_state)
+          (State.Block.known_invalid chain_db.chain_state)
           (Block_header.hash head :: hist) >>= fun known_invalid ->
         if not known_invalid then
-          net_db.callback.notify_branch state.gid locator ;
+          chain_db.callback.notify_branch state.gid locator ;
         (* TODO Kickban *)
         Lwt.return_unit
 
-    | Deactivate net_id ->
-        may_handle state net_id @@ fun net_db ->
-        deactivate state net_db ;
-        Net_id.Table.remove state.peer_active_nets net_id ;
+    | Deactivate chain_id ->
+        may_handle state chain_id @@ fun chain_db ->
+        deactivate state chain_db ;
+        Chain_id.Table.remove state.peer_active_chains chain_id ;
         Lwt.return_unit
 
-    | Get_current_head net_id ->
-        may_handle state net_id @@ fun net_db ->
-        State.Current_mempool.get net_db.net_state >>= fun (head, mempool) ->
+    | Get_current_head chain_id ->
+        may_handle state chain_id @@ fun chain_db ->
+        State.Current_mempool.get chain_db.chain_state >>= fun (head, mempool) ->
         (* TODO bound the sent mempool size *)
         ignore
         @@ P2p.try_send global_db.p2p state.conn
-        @@ Current_head (net_id, head, mempool) ;
+        @@ Current_head (chain_id, head, mempool) ;
         Lwt.return_unit
 
-    | Current_head (net_id, header, mempool) ->
-        may_handle state net_id @@ fun net_db ->
+    | Current_head (chain_id, header, mempool) ->
+        may_handle state chain_id @@ fun chain_db ->
         let head = Block_header.hash header in
-        State.Block.known_invalid net_db.net_state head >>= fun known_invalid ->
+        State.Block.known_invalid chain_db.chain_state head >>= fun known_invalid ->
         if not known_invalid then
-          net_db.callback.notify_head state.gid header mempool ;
+          chain_db.callback.notify_head state.gid header mempool ;
         (* TODO Kickban *)
         Lwt.return_unit
 
@@ -514,7 +514,7 @@ module P2p_reader = struct
              | None ->
                  (* TODO: Blame request of unadvertised blocks ? *)
                  Lwt.return_unit
-             | Some (_net_id, header) ->
+             | Some (_chain_id, header) ->
                  ignore @@
                  P2p.try_send global_db.p2p state.conn (Block_header header) ;
                  Lwt.return_unit)
@@ -526,9 +526,9 @@ module P2p_reader = struct
         | None ->
             (* TODO some penalty. *)
             Lwt.return_unit
-        | Some net_db ->
+        | Some chain_db ->
             Raw_block_header.Table.notify
-              net_db.block_header_db.table state.gid hash block >>= fun () ->
+              chain_db.block_header_db.table state.gid hash block >>= fun () ->
             Lwt.return_unit
       end
 
@@ -539,7 +539,7 @@ module P2p_reader = struct
              | None ->
                  (* TODO: Blame request of unadvertised operations ? *)
                  Lwt.return_unit
-             | Some (_net_id, op) ->
+             | Some (_chain_id, op) ->
                  ignore @@
                  P2p.try_send global_db.p2p state.conn (Operation op) ;
                  Lwt.return_unit)
@@ -551,9 +551,9 @@ module P2p_reader = struct
         | None ->
             (* TODO some penalty. *)
             Lwt.return_unit
-        | Some net_db ->
+        | Some chain_db ->
             Raw_operation.Table.notify
-              net_db.operation_db.table state.gid hash operation >>= fun () ->
+              chain_db.operation_db.table state.gid hash operation >>= fun () ->
             Lwt.return_unit
       end
 
@@ -595,9 +595,9 @@ module P2p_reader = struct
         | None ->
             (* TODO some penalty. *)
             Lwt.return_unit
-        | Some net_db ->
+        | Some chain_db ->
             Raw_operation_hashes.Table.notify
-              net_db.operation_hashes_db.table state.gid
+              chain_db.operation_hashes_db.table state.gid
               (block, ofs) (ops, path) >>= fun () ->
             Lwt.return_unit
       end
@@ -621,9 +621,9 @@ module P2p_reader = struct
         | None ->
             (* TODO some penalty. *)
             Lwt.return_unit
-        | Some net_db ->
+        | Some chain_db ->
             Raw_operations.Table.notify
-              net_db.operations_db.table state.gid
+              chain_db.operations_db.table state.gid
               (block, ofs) (ops, path) >>= fun () ->
             Lwt.return_unit
       end
@@ -636,9 +636,9 @@ module P2p_reader = struct
         handle_msg global_db state msg >>= fun () ->
         worker_loop global_db state
     | Error _ ->
-        Net_id.Table.iter
+        Chain_id.Table.iter
           (fun _ -> deactivate state)
-          state.peer_active_nets ;
+          state.peer_active_chains ;
         P2p_peer.Table.remove global_db.p2p_readers state.gid ;
         Lwt.return_unit
 
@@ -646,14 +646,14 @@ module P2p_reader = struct
     let canceler = Lwt_canceler.create () in
     let state = {
       conn ; gid ; canceler ;
-      peer_active_nets = Net_id.Table.create 17 ;
+      peer_active_chains = Chain_id.Table.create 17 ;
       worker = Lwt.return_unit ;
     } in
-    Net_id.Table.iter (fun net_id _net_db ->
+    Chain_id.Table.iter (fun chain_id _chain_db ->
         Lwt.async begin fun () ->
-          P2p.send db.p2p conn (Get_current_branch net_id)
+          P2p.send db.p2p conn (Get_current_branch chain_id)
         end)
-      db.active_nets ;
+      db.active_chains ;
     state.worker <-
       Lwt_utils.worker
         (Format.asprintf "db_network_reader.%a"
@@ -688,21 +688,21 @@ let create disk p2p =
       send = raw_try_send p2p ;
     } in
   let protocol_db = Raw_protocol.create global_request disk in
-  let active_nets = Net_id.Table.create 17 in
+  let active_chains = Chain_id.Table.create 17 in
   let p2p_readers = P2p_peer.Table.create 17 in
   let block_input = Lwt_watcher.create_input () in
   let operation_input = Lwt_watcher.create_input () in
   let db =
     { p2p ; p2p_readers ; disk ;
-      active_nets ; protocol_db ;
+      active_chains ; protocol_db ;
       block_input ; operation_input } in
   P2p.on_new_connection p2p (P2p_reader.run db) ;
   P2p.iter_connections p2p (P2p_reader.run db) ;
   db
 
-let activate ({ p2p ; active_nets } as global_db) net_state =
-  let net_id = State.Net.id net_state in
-  match Net_id.Table.find active_nets net_id with
+let activate ({ p2p ; active_chains } as global_db) chain_state =
+  let chain_id = State.Chain.id chain_state in
+  match Chain_id.Table.find active_chains chain_id with
   | exception Not_found ->
       let active_peers = ref P2p_peer.Set.empty in
       let p2p_request =
@@ -712,50 +712,50 @@ let activate ({ p2p ; active_nets } as global_db) net_state =
         } in
       let operation_db =
         Raw_operation.create
-          ~global_input:global_db.operation_input p2p_request net_state in
+          ~global_input:global_db.operation_input p2p_request chain_state in
       let block_header_db =
         Raw_block_header.create
-          ~global_input:global_db.block_input p2p_request net_state in
+          ~global_input:global_db.block_input p2p_request chain_state in
       let operation_hashes_db =
-        Raw_operation_hashes.create p2p_request net_state in
+        Raw_operation_hashes.create p2p_request chain_state in
       let operations_db =
-        Raw_operations.create p2p_request net_state in
-      let net = {
+        Raw_operations.create p2p_request chain_state in
+      let chain = {
         global_db ; operation_db ; block_header_db ;
         operation_hashes_db ; operations_db ;
-        net_state ; callback = noop_callback ; active_peers ;
+        chain_state ; callback = noop_callback ; active_peers ;
         active_connections = P2p_peer.Table.create 53 ;
       } in
       P2p.iter_connections p2p (fun _peer_id conn ->
           Lwt.async begin fun () ->
-            P2p.send p2p conn (Get_current_branch net_id)
+            P2p.send p2p conn (Get_current_branch chain_id)
           end) ;
-      Net_id.Table.add active_nets net_id net ;
-      net
-  | net ->
-      net
+      Chain_id.Table.add active_chains chain_id chain ;
+      chain
+  | chain ->
+      chain
 
-let set_callback net_db callback =
-  net_db.callback <- callback
+let set_callback chain_db callback =
+  chain_db.callback <- callback
 
-let deactivate net_db =
-  let { active_nets ; p2p } = net_db.global_db in
-  let net_id = State.Net.id net_db.net_state in
-  Net_id.Table.remove active_nets net_id ;
+let deactivate chain_db =
+  let { active_chains ; p2p } = chain_db.global_db in
+  let chain_id = State.Chain.id chain_db.chain_state in
+  Chain_id.Table.remove active_chains chain_id ;
   P2p_peer.Table.iter
     (fun _peer_id reader ->
-       P2p_reader.deactivate reader net_db  ;
+       P2p_reader.deactivate reader chain_db  ;
        Lwt.async begin fun () ->
-         P2p.send p2p reader.conn (Deactivate net_id)
+         P2p.send p2p reader.conn (Deactivate chain_id)
        end)
-    net_db.active_connections ;
-  Raw_operation.shutdown net_db.operation_db >>= fun () ->
-  Raw_block_header.shutdown net_db.block_header_db >>= fun () ->
+    chain_db.active_connections ;
+  Raw_operation.shutdown chain_db.operation_db >>= fun () ->
+  Raw_block_header.shutdown chain_db.block_header_db >>= fun () ->
   Lwt.return_unit >>= fun () ->
   Lwt.return_unit
 
-let get_net { active_nets } net_id =
-  try Some (Net_id.Table.find active_nets net_id)
+let get_chain { active_chains } chain_id =
+  try Some (Chain_id.Table.find active_chains chain_id)
   with Not_found -> None
 
 let disconnect { global_db = { p2p } } peer_id =
@@ -763,43 +763,43 @@ let disconnect { global_db = { p2p } } peer_id =
   | None -> Lwt.return_unit
   | Some conn -> P2p.disconnect p2p conn
 
-let shutdown { p2p ; p2p_readers ; active_nets } =
+let shutdown { p2p ; p2p_readers ; active_chains } =
   P2p_peer.Table.fold
     (fun _peer_id reader acc ->
        P2p_reader.shutdown reader >>= fun () -> acc)
     p2p_readers
     Lwt.return_unit >>= fun () ->
-  Net_id.Table.fold
-    (fun _ net_db acc ->
-       Raw_operation.shutdown net_db.operation_db >>= fun () ->
-       Raw_block_header.shutdown net_db.block_header_db >>= fun () ->
+  Chain_id.Table.fold
+    (fun _ chain_db acc ->
+       Raw_operation.shutdown chain_db.operation_db >>= fun () ->
+       Raw_block_header.shutdown chain_db.block_header_db >>= fun () ->
        acc)
-    active_nets
+    active_chains
     Lwt.return_unit >>= fun () ->
   P2p.shutdown p2p >>= fun () ->
   Lwt.return_unit
 
-let clear_block net_db hash n =
-  Raw_operations.clear_all net_db.operations_db.table hash n ;
-  Raw_operation_hashes.clear_all net_db.operation_hashes_db.table hash n ;
-  Raw_block_header.Table.clear_or_cancel net_db.block_header_db.table hash
+let clear_block chain_db hash n =
+  Raw_operations.clear_all chain_db.operations_db.table hash n ;
+  Raw_operation_hashes.clear_all chain_db.operation_hashes_db.table hash n ;
+  Raw_block_header.Table.clear_or_cancel chain_db.block_header_db.table hash
 
-let commit_block net_db hash header operations result =
+let commit_block chain_db hash header operations result =
   assert (Block_hash.equal hash (Block_header.hash header)) ;
   assert (List.length operations = header.shell.validation_passes) ;
-  State.Block.store net_db.net_state header operations result >>=? fun res ->
-  clear_block net_db hash header.shell.validation_passes ;
+  State.Block.store chain_db.chain_state header operations result >>=? fun res ->
+  clear_block chain_db hash header.shell.validation_passes ;
   return res
 
-let commit_invalid_block net_db hash header errors =
+let commit_invalid_block chain_db hash header errors =
   assert (Block_hash.equal hash (Block_header.hash header)) ;
-  State.Block.store_invalid net_db.net_state header errors >>=? fun res ->
-  clear_block net_db hash header.shell.validation_passes ;
+  State.Block.store_invalid chain_db.chain_state header errors >>=? fun res ->
+  clear_block chain_db hash header.shell.validation_passes ;
   return res
 
-let inject_operation net_db h op =
+let inject_operation chain_db h op =
   assert (Operation_hash.equal h (Operation.hash op)) ;
-  Raw_operation.Table.inject net_db.operation_db.table h op
+  Raw_operation.Table.inject chain_db.operation_db.table h op
 
 let commit_protocol db h p =
   State.Protocol.store db.disk p >>= fun res ->
@@ -844,9 +844,9 @@ end
 module Block_header = struct
   type t = Block_header.t
   include (Make (Raw_block_header.Table) (struct
-             type t = net_db
-             let proj net = net.block_header_db.table
-           end) : Distributed_db_functors.DISTRIBUTED_DB with type t := net_db
+             type t = chain_db
+             let proj chain = chain.block_header_db.table
+           end) : Distributed_db_functors.DISTRIBUTED_DB with type t := chain_db
                                                           and type key := Block_hash.t
                                                           and type value := Block_header.t
                                                           and type param := unit)
@@ -854,22 +854,22 @@ end
 
 module Operation_hashes =
   Make (Raw_operation_hashes.Table) (struct
-    type t = net_db
-    let proj net = net.operation_hashes_db.table
+    type t = chain_db
+    let proj chain = chain.operation_hashes_db.table
   end)
 
 module Operations =
   Make (Raw_operations.Table) (struct
-    type t = net_db
-    let proj net = net.operations_db.table
+    type t = chain_db
+    let proj chain = chain.operations_db.table
   end)
 
 module Operation = struct
   include Operation
   include (Make (Raw_operation.Table) (struct
-             type t = net_db
-             let proj net = net.operation_db.table
-           end) : Distributed_db_functors.DISTRIBUTED_DB with type t := net_db
+             type t = chain_db
+             let proj chain = chain.operation_db.table
+           end) : Distributed_db_functors.DISTRIBUTED_DB with type t := chain_db
                                                           and type key := Operation_hash.t
                                                           and type value := Operation.t
                                                           and type param := unit)
@@ -887,46 +887,46 @@ module Protocol = struct
 end
 
 
-let broadcast net_db msg =
+let broadcast chain_db msg =
   P2p_peer.Table.iter
     (fun _peer_id state ->
-       ignore (P2p.try_send net_db.global_db.p2p state.conn msg))
-    net_db.active_connections
+       ignore (P2p.try_send chain_db.global_db.p2p state.conn msg))
+    chain_db.active_connections
 
-let try_send net_db peer_id msg =
+let try_send chain_db peer_id msg =
   try
-    let conn = P2p_peer.Table.find net_db.active_connections peer_id in
-    ignore (P2p.try_send net_db.global_db.p2p conn.conn msg : bool)
+    let conn = P2p_peer.Table.find chain_db.active_connections peer_id in
+    ignore (P2p.try_send chain_db.global_db.p2p conn.conn msg : bool)
   with Not_found -> ()
 
-let send net_db ?peer msg =
+let send chain_db ?peer msg =
   match peer with
-  | Some peer -> try_send net_db peer msg
-  | None -> broadcast net_db msg
+  | Some peer -> try_send chain_db peer msg
+  | None -> broadcast chain_db msg
 
 module Request = struct
 
-  let current_head net_db ?peer () =
-    let net_id = State.Net.id net_db.net_state in
-    send net_db ?peer @@ Get_current_head net_id
+  let current_head chain_db ?peer () =
+    let chain_id = State.Chain.id chain_db.chain_state in
+    send chain_db ?peer @@ Get_current_head chain_id
 
-  let current_branch net_db ?peer () =
-    let net_id = State.Net.id net_db.net_state in
-    send net_db ?peer @@ Get_current_branch net_id
+  let current_branch chain_db ?peer () =
+    let chain_id = State.Chain.id chain_db.chain_state in
+    send chain_db ?peer @@ Get_current_branch chain_id
 
 end
 
 module Advertise = struct
 
-  let current_head net_db ?peer ?(mempool = Mempool.empty) head =
-    let net_id = State.Net.id net_db.net_state in
-    assert (Net_id.equal net_id (State.Block.net_id head)) ;
-    send net_db ?peer @@
-    Current_head (net_id, State.Block.header head, mempool)
+  let current_head chain_db ?peer ?(mempool = Mempool.empty) head =
+    let chain_id = State.Chain.id chain_db.chain_state in
+    assert (Chain_id.equal chain_id (State.Block.chain_id head)) ;
+    send chain_db ?peer @@
+    Current_head (chain_id, State.Block.header head, mempool)
 
-  let current_branch net_db ?peer locator =
-    let net_id = State.Net.id net_db.net_state in
-    send net_db ?peer @@ Current_branch (net_id, locator) ;
+  let current_branch chain_db ?peer locator =
+    let chain_id = State.Chain.id chain_db.chain_state in
+    send chain_db ?peer @@ Current_branch (chain_id, locator) ;
     Lwt.return_unit
 
 end
diff --git a/src/lib_shell/distributed_db.mli b/src/lib_shell/distributed_db.mli
index 822ada482..44dfaf1e9 100644
--- a/src/lib_shell/distributed_db.mli
+++ b/src/lib_shell/distributed_db.mli
@@ -25,21 +25,21 @@ val shutdown: t -> unit Lwt.t
 
 (** {1 Network database} *)
 
-(** An instance of the distributed DB for a given network (mainnet,
-    current testnet, ...) *)
-type net_db
+(** An instance of the distributed DB for a given chain (mainchain,
+    current testchain, ...) *)
+type chain_db
 
-(** Activate a given network. The node will notify its neighbours that
-    it now handles the given network and that it expects notification
+(** Activate a given chain. The node will notify its neighbours that
+    it now handles the given chain and that it expects notification
     for new head or new operations. *)
-val activate: t -> State.Net.t -> net_db
+val activate: t -> State.Chain.t -> chain_db
 
-(** Look for the database of an active network. *)
-val get_net: t -> Net_id.t -> net_db option
+(** Look for the database of an active chain. *)
+val get_chain: t -> Chain_id.t -> chain_db option
 
-(** Deactivate a given network. The node will notify its neighbours
-    that it does not care anymore about this network. *)
-val deactivate: net_db -> unit Lwt.t
+(** Deactivate a given chain. The node will notify its neighbours
+    that it does not care anymore about this chain. *)
+val deactivate: chain_db -> unit Lwt.t
 
 type callback = {
   notify_branch: P2p_peer.Id.t -> Block_locator.t -> unit ;
@@ -49,43 +49,43 @@ type callback = {
 
 (** Register all the possible callback from the distributed DB to the
     validator. *)
-val set_callback: net_db -> callback -> unit
+val set_callback: chain_db -> callback -> unit
 
 (** Kick a given peer. *)
-val disconnect: net_db -> P2p_peer.Id.t -> unit Lwt.t
+val disconnect: chain_db -> P2p_peer.Id.t -> unit Lwt.t
 
 (** Various accessors. *)
-val net_state: net_db -> State.Net.t
-val db: net_db -> db
+val chain_state: chain_db -> State.Chain.t
+val db: chain_db -> db
 
 (** {1 Sending messages} *)
 
 module Request : sig
 
   (** Send to a given peer, or to all known active peers for the
-      network, a friendly request "Hey, what's your current branch
+      chain, a friendly request "Hey, what's your current branch
       ?". The expected answer is a `Block_locator.t.`. *)
-  val current_branch: net_db -> ?peer:P2p_peer.Id.t -> unit -> unit
+  val current_branch: chain_db -> ?peer:P2p_peer.Id.t -> unit -> unit
 
   (** Send to a given peer, or to all known active peers for the
-      given network, a friendly request "Hey, what's your current
+      given chain, a friendly request "Hey, what's your current
       branch ?". The expected answer is a `Block_locator.t.`. *)
-  val current_head: net_db -> ?peer:P2p_peer.Id.t -> unit -> unit
+  val current_head: chain_db -> ?peer:P2p_peer.Id.t -> unit -> unit
 
 end
 
 module Advertise : sig
 
   (** Notify a given peer, or all known active peers for the
-      network, of a new head and possibly of new operations. *)
+      chain, of a new head and possibly of new operations. *)
   val current_head:
-    net_db -> ?peer:P2p_peer.Id.t ->
+    chain_db -> ?peer:P2p_peer.Id.t ->
     ?mempool:Mempool.t -> State.Block.t -> unit
 
   (** Notify a given peer, or all known active peers for the
-      network, of a new head and its sparse history. *)
+      chain, of a new head and its sparse history. *)
   val current_branch:
-    net_db -> ?peer:P2p_peer.Id.t ->
+    chain_db -> ?peer:P2p_peer.Id.t ->
     Block_locator.t -> unit Lwt.t
 
 end
@@ -95,19 +95,19 @@ end
 (** Index of block headers. *)
 module Block_header : sig
   type t = Block_header.t (* avoid shadowing. *)
-  include DISTRIBUTED_DB with type t := net_db
+  include DISTRIBUTED_DB with type t := chain_db
                           and type key := Block_hash.t
                           and type value := Block_header.t
                           and type param := unit
 end
 
-(** Lookup for block header in any active networks *)
+(** Lookup for block header in any active chains *)
 val read_block_header:
-  db -> Block_hash.t -> (Net_id.t * Block_header.t) option Lwt.t
+  db -> Block_hash.t -> (Chain_id.t * Block_header.t) option Lwt.t
 
 (** Index of all the operations of a given block (per validation pass). *)
 module Operations :
-  DISTRIBUTED_DB with type t := net_db
+  DISTRIBUTED_DB with type t := chain_db
                   and type key = Block_hash.t * int
                   and type value = Operation.t list
                   and type param := Operation_list_list_hash.t
@@ -115,14 +115,14 @@ module Operations :
 (** Index of all the hashes of operations of a given block (per
     validation pass). *)
 module Operation_hashes :
-  DISTRIBUTED_DB with type t := net_db
+  DISTRIBUTED_DB with type t := chain_db
                   and type key = Block_hash.t * int
                   and type value = Operation_hash.t list
                   and type param := Operation_list_list_hash.t
 
 (** Store on disk all the data associated to a valid block. *)
 val commit_block:
-  net_db ->
+  chain_db ->
   Block_hash.t ->
   Block_header.t -> Operation.t list list ->
   Updater.validation_result ->
@@ -130,11 +130,11 @@ val commit_block:
 
 (** Store on disk all the data associated to an invalid block. *)
 val commit_invalid_block:
-  net_db ->
+  chain_db ->
   Block_hash.t -> Block_header.t -> Error_monad.error list ->
   bool tzresult Lwt.t
 
-(** Monitor all the fetched block headers (for all activate networks). *)
+(** Monitor all the fetched block headers (for all activate chains). *)
 val watch_block_header:
   t -> (Block_hash.t * Block_header.t) Lwt_stream.t * Lwt_watcher.stopper
 
@@ -144,7 +144,7 @@ val watch_block_header:
 (** Index of operations (for the mempool). *)
 module Operation : sig
   type t = Operation.t (* avoid shadowing. *)
-  include DISTRIBUTED_DB with type t := net_db
+  include DISTRIBUTED_DB with type t := chain_db
                           and type key := Operation_hash.t
                           and type value := Operation.t
                           and type param := unit
@@ -152,9 +152,9 @@ end
 
 (** Inject a new operation in the local index (memory only). *)
 val inject_operation:
-  net_db -> Operation_hash.t -> Operation.t -> bool Lwt.t
+  chain_db -> Operation_hash.t -> Operation.t -> bool Lwt.t
 
-(** Monitor all the fetched operations (for all activate networks). *)
+(** Monitor all the fetched operations (for all activate chains). *)
 val watch_operation:
   t -> (Operation_hash.t * Operation.t) Lwt_stream.t * Lwt_watcher.stopper
 
diff --git a/src/lib_shell/distributed_db_message.ml b/src/lib_shell/distributed_db_message.ml
index 9b7e601c9..912e39c4d 100644
--- a/src/lib_shell/distributed_db_message.ml
+++ b/src/lib_shell/distributed_db_message.ml
@@ -9,12 +9,12 @@
 
 type t =
 
-  | Get_current_branch of Net_id.t
-  | Current_branch of Net_id.t * Block_locator.t
-  | Deactivate of Net_id.t
+  | Get_current_branch of Chain_id.t
+  | Current_branch of Chain_id.t * Block_locator.t
+  | Deactivate of Chain_id.t
 
-  | Get_current_head of Net_id.t
-  | Current_head of Net_id.t * Block_header.t * Mempool.t
+  | Get_current_head of Chain_id.t
+  | Current_head of Chain_id.t * Block_header.t * Mempool.t
 
   | Get_block_headers of Block_hash.t list
   | Block_header of Block_header.t
@@ -42,46 +42,46 @@ let encoding =
   [
     case ~tag:0x10
       (obj1
-         (req "get_current_branch" Net_id.encoding))
+         (req "get_current_branch" Chain_id.encoding))
       (function
-        | Get_current_branch net_id -> Some net_id
+        | Get_current_branch chain_id -> Some chain_id
         | _ -> None)
-      (fun net_id -> Get_current_branch net_id) ;
+      (fun chain_id -> Get_current_branch chain_id) ;
 
     case ~tag:0x11
       (obj2
-         (req "net_id" Net_id.encoding)
+         (req "chain_id" Chain_id.encoding)
          (req "current_branch" Block_locator.encoding))
       (function
-        | Current_branch (net_id, locator) -> Some (net_id, locator)
+        | Current_branch (chain_id, locator) -> Some (chain_id, locator)
         | _ -> None)
-      (fun (net_id, locator) -> Current_branch (net_id, locator)) ;
+      (fun (chain_id, locator) -> Current_branch (chain_id, locator)) ;
 
     case ~tag:0x12
       (obj1
-         (req "deactivate" Net_id.encoding))
+         (req "deactivate" Chain_id.encoding))
       (function
-        | Deactivate net_id -> Some net_id
+        | Deactivate chain_id -> Some chain_id
         | _ -> None)
-      (fun net_id -> Deactivate net_id) ;
+      (fun chain_id -> Deactivate chain_id) ;
 
     case ~tag:0x13
       (obj1
-         (req "get_current_head" Net_id.encoding))
+         (req "get_current_head" Chain_id.encoding))
       (function
-        | Get_current_head net_id -> Some net_id
+        | Get_current_head chain_id -> Some chain_id
         | _ -> None)
-      (fun net_id -> Get_current_branch net_id) ;
+      (fun chain_id -> Get_current_branch chain_id) ;
 
     case ~tag:0x14
       (obj3
-         (req "net_id" Net_id.encoding)
+         (req "chain_id" Chain_id.encoding)
          (req "current_block_header" (dynamic_size Block_header.encoding))
          (req "current_mempool" Mempool.encoding))
       (function
-        | Current_head (net_id, bh, mempool) -> Some (net_id, bh, mempool)
+        | Current_head (chain_id, bh, mempool) -> Some (chain_id, bh, mempool)
         | _ -> None)
-      (fun (net_id, bh, mempool) -> Current_head (net_id, bh, mempool)) ;
+      (fun (chain_id, bh, mempool) -> Current_head (chain_id, bh, mempool)) ;
 
     case ~tag:0x20
       (obj1 (req "get_block_headers" (list Block_hash.encoding)))
diff --git a/src/lib_shell/distributed_db_message.mli b/src/lib_shell/distributed_db_message.mli
index 294554b8f..29d43cdbe 100644
--- a/src/lib_shell/distributed_db_message.mli
+++ b/src/lib_shell/distributed_db_message.mli
@@ -11,12 +11,12 @@
 
 type t =
 
-  | Get_current_branch of Net_id.t
-  | Current_branch of Net_id.t * Block_locator.t
-  | Deactivate of Net_id.t
+  | Get_current_branch of Chain_id.t
+  | Current_branch of Chain_id.t * Block_locator.t
+  | Deactivate of Chain_id.t
 
-  | Get_current_head of Net_id.t
-  | Current_head of Net_id.t * Block_header.t * Mempool.t
+  | Get_current_head of Chain_id.t
+  | Current_head of Chain_id.t * Block_header.t * Mempool.t
 
   | Get_block_headers of Block_hash.t list
   | Block_header of Block_header.t
diff --git a/src/lib_shell/node.ml b/src/lib_shell/node.ml
index dc50483ce..85884c493 100644
--- a/src/lib_shell/node.ml
+++ b/src/lib_shell/node.ml
@@ -10,12 +10,12 @@
 open Lwt.Infix
 open Logging.Node.Worker
 
-let inject_operation validator ?net_id bytes =
+let inject_operation validator ?chain_id bytes =
   let t =
     match Data_encoding.Binary.of_bytes Operation.encoding bytes with
     | None -> failwith "Can't parse the operation"
     | Some op ->
-        Validator.inject_operation validator ?net_id op
+        Validator.inject_operation validator ?chain_id op
   in
   let hash = Operation_hash.hash_bytes [bytes] in
   Lwt.return (hash, t)
@@ -40,23 +40,23 @@ let inject_protocol state ?force:_ proto =
   in
   Lwt.return (hash, validation)
 
-let inject_block validator ?force ?net_id bytes operations =
+let inject_block validator ?force ?chain_id bytes operations =
   Validator.validate_block
-    validator ?force ?net_id bytes operations >>=? fun (hash, block) ->
+    validator ?force ?chain_id bytes operations >>=? fun (hash, block) ->
   return (hash, (block >>=? fun _ -> return ()))
 
 type t = {
   state: State.t ;
   distributed_db: Distributed_db.t ;
   validator: Validator.t ;
-  mainnet_validator: Net_validator.t ;
+  mainchain_validator: Chain_validator.t ;
   inject_block:
     ?force:bool ->
-    ?net_id:Net_id.t ->
+    ?chain_id:Chain_id.t ->
     MBytes.t -> Operation.t list list ->
     (Block_hash.t * unit tzresult Lwt.t) tzresult Lwt.t ;
   inject_operation:
-    ?net_id:Net_id.t -> MBytes.t ->
+    ?chain_id:Chain_id.t -> MBytes.t ->
     (Operation_hash.t * unit tzresult Lwt.t) Lwt.t ;
   inject_protocol:
     ?force:bool -> Protocol.t ->
@@ -65,13 +65,13 @@ type t = {
   shutdown: unit -> unit Lwt.t ;
 }
 
-let init_p2p net_params =
-  match net_params with
+let init_p2p p2p_params =
+  match p2p_params with
   | None ->
       lwt_log_notice "P2P layer is disabled" >>= fun () ->
       Error_monad.return (P2p.faked_network Distributed_db_metadata.cfg)
   | Some (config, limits) ->
-      lwt_log_notice "bootstraping network..." >>= fun () ->
+      lwt_log_notice "bootstraping chain..." >>= fun () ->
       P2p.create
         ~config ~limits
         Distributed_db_metadata.cfg
@@ -80,12 +80,12 @@ let init_p2p net_params =
       Error_monad.return p2p
 
 type config = {
-  genesis: State.Net.genesis ;
+  genesis: State.Chain.genesis ;
   store_root: string ;
   context_root: string ;
   patch_context: (Context.t -> Context.t Lwt.t) option ;
   p2p: (P2p.config * P2p.limits) option ;
-  test_network_max_tll: int option ;
+  test_chain_max_tll: int option ;
 }
 
 and peer_validator_limits = Peer_validator.limits = {
@@ -107,25 +107,25 @@ and block_validator_limits = Block_validator.limits = {
   worker_limits : Worker_types.limits ;
 }
 
-and net_validator_limits = Net_validator.limits = {
+and chain_validator_limits = Chain_validator.limits = {
   bootstrap_threshold: int ;
   worker_limits : Worker_types.limits ;
 }
 
-let may_create_net state genesis =
-  State.Net.get state (Net_id.of_block_hash genesis.State.Net.block) >>= function
-  | Ok net -> Lwt.return net
+let may_create_chain state genesis =
+  State.Chain.get state (Chain_id.of_block_hash genesis.State.Chain.block) >>= function
+  | Ok chain -> Lwt.return chain
   | Error _ ->
-      State.Net.create state genesis
+      State.Chain.create state genesis
 
 let create { genesis ; store_root ; context_root ;
-             patch_context ; p2p = net_params ;
-             test_network_max_tll = max_child_ttl }
+             patch_context ; p2p = p2p_params ;
+             test_chain_max_tll = max_child_ttl }
     peer_validator_limits
     block_validator_limits
     prevalidator_limits
-    net_validator_limits =
-  init_p2p net_params >>=? fun p2p ->
+    chain_validator_limits =
+  init_p2p p2p_params >>=? fun p2p ->
   State.read
     ~store_root ~context_root ?patch_context () >>=? fun state ->
   let distributed_db = Distributed_db.create state p2p in
@@ -133,10 +133,10 @@ let create { genesis ; store_root ; context_root ;
     peer_validator_limits
     block_validator_limits
     prevalidator_limits
-    net_validator_limits >>= fun validator ->
-  may_create_net state genesis >>= fun mainnet_state ->
+    chain_validator_limits >>= fun validator ->
+  may_create_chain state genesis >>= fun mainchain_state ->
   Validator.activate validator
-    ?max_child_ttl mainnet_state >>= fun mainnet_validator ->
+    ?max_child_ttl mainchain_state >>= fun mainchain_validator ->
   let shutdown () =
     P2p.shutdown p2p >>= fun () ->
     Validator.shutdown validator >>= fun () ->
@@ -147,7 +147,7 @@ let create { genesis ; store_root ; context_root ;
     state ;
     distributed_db ;
     validator ;
-    mainnet_validator ;
+    mainchain_validator ;
     inject_block = inject_block validator ;
     inject_operation = inject_operation validator ;
     inject_protocol = inject_protocol state ;
@@ -162,7 +162,7 @@ module RPC = struct
   type block = Block_services.block
   type block_info = Block_services.block_info = {
     hash: Block_hash.t ;
-    net_id: Net_id.t ;
+    chain_id: Chain_id.t ;
     level: Int32.t ;
     proto_level: int ; (* uint8 *)
     predecessor: Block_hash.t ;
@@ -174,7 +174,7 @@ module RPC = struct
     data: MBytes.t ;
     operations: (Operation_hash.t * Operation.t) list list option ;
     protocol: Protocol_hash.t ;
-    test_network: Test_network_status.t ;
+    test_chain: Test_chain_status.t ;
   }
 
   let convert (block: State.Block.t) =
@@ -185,10 +185,10 @@ module RPC = struct
       List.map (List.map (fun op -> (Operation.hash op, op))) operations in
     State.Block.context block >>= fun context ->
     Context.get_protocol context >>= fun protocol ->
-    Context.get_test_network context >>= fun test_network ->
+    Context.get_test_chain context >>= fun test_chain ->
     Lwt.return {
       hash ;
-      net_id = State.Block.net_id block ;
+      chain_id = State.Block.chain_id block ;
       level = header.shell.level ;
       proto_level = header.shell.proto_level ;
       predecessor = header.shell.predecessor ;
@@ -200,7 +200,7 @@ module RPC = struct
       data = header.proto ;
       operations = Some operations ;
       protocol ;
-      test_network ;
+      test_chain ;
     }
 
   let inject_block node = node.inject_block
@@ -219,21 +219,21 @@ module RPC = struct
       "BLockPrevaLidationPrevaLidationPrevaLidationPrZ4mr6"
 
   let get_validator node = function
-    | `Genesis | `Head _ | `Prevalidation -> node.mainnet_validator
+    | `Genesis | `Head _ | `Prevalidation -> node.mainchain_validator
     | `Test_head _ | `Test_prevalidation ->
-        match Net_validator.child node.mainnet_validator with
+        match Chain_validator.child node.mainchain_validator with
         | None -> raise Not_found
         | Some v -> v
 
   let get_validator_per_hash node hash =
     State.read_block_exn node.state hash >>= fun block ->
-    let net_id = State.Block.net_id block in
-    if Net_id.equal (Net_validator.net_id node.mainnet_validator) net_id then
-      Lwt.return (Some node.mainnet_validator)
+    let chain_id = State.Block.chain_id block in
+    if Chain_id.equal (Chain_validator.chain_id node.mainchain_validator) chain_id then
+      Lwt.return (Some node.mainchain_validator)
     else
-      match Net_validator.child node.mainnet_validator with
+      match Chain_validator.child node.mainchain_validator with
       | Some test_validator ->
-          if Net_id.equal (Net_validator.net_id test_validator) net_id then
+          if Chain_id.equal (Chain_validator.chain_id test_validator) chain_id then
             Lwt.return_some test_validator
           else
             Lwt.return_none
@@ -245,42 +245,42 @@ module RPC = struct
   let read_valid_block_exn node h =
     State.read_block_exn node.state h
 
-  let rec predecessor net_db n v =
+  let rec predecessor chain_db n v =
     if n <= 0 then
       Lwt.return v
     else
       State.Block.predecessor v >>= function
       | None -> Lwt.return v
-      | Some v -> predecessor net_db (n-1) v
+      | Some v -> predecessor chain_db (n-1) v
 
   let block_info node (block: block) =
     match block with
     | `Genesis ->
-        let net_state = Net_validator.net_state node.mainnet_validator in
-        Chain.genesis net_state >>= convert
+        let chain_state = Chain_validator.chain_state node.mainchain_validator in
+        Chain.genesis chain_state >>= convert
     | ( `Head n | `Test_head n ) as block ->
         let validator = get_validator node block in
-        let net_db = Net_validator.net_db validator in
-        let net_state = Net_validator.net_state validator in
-        Chain.head net_state >>= fun head ->
-        predecessor net_db n head >>= convert
+        let chain_db = Chain_validator.chain_db validator in
+        let chain_state = Chain_validator.chain_state validator in
+        Chain.head chain_state >>= fun head ->
+        predecessor chain_db n head >>= convert
     | `Hash h ->
         read_valid_block_exn node h >>= convert
     | ( `Prevalidation | `Test_prevalidation ) as block ->
         let validator = get_validator node block in
-        let pv = Net_validator.prevalidator validator in
-        let net_state = Net_validator.net_state validator in
-        Chain.head net_state >>= fun head ->
+        let pv = Chain_validator.prevalidator validator in
+        let chain_state = Chain_validator.chain_state validator in
+        Chain.head chain_state >>= fun head ->
         let head_header = State.Block.header head in
         let head_hash = State.Block.hash head in
-        let head_net_id = State.Block.net_id head in
+        let head_chain_id = State.Block.chain_id head in
         State.Block.context head >>= fun head_context ->
         Context.get_protocol head_context >>= fun head_protocol ->
         Prevalidator.context pv >>= function
         | Error _ -> Lwt.fail Not_found
         | Ok { context ; fitness } ->
             Context.get_protocol context >>= fun protocol ->
-            Context.get_test_network context >>= fun test_network ->
+            Context.get_test_chain context >>= fun test_chain ->
             let proto_level =
               if Protocol_hash.equal protocol head_protocol then
                 head_header.shell.proto_level
@@ -306,8 +306,8 @@ module RPC = struct
                 operations = Some operations ;
                 context = Context_hash.zero ;
                 data = MBytes.of_string "" ;
-                net_id = head_net_id ;
-                test_network ;
+                chain_id = head_chain_id ;
+                test_chain ;
               }
 
   let rpc_context block : Updater.rpc_context Lwt.t =
@@ -324,16 +324,16 @@ module RPC = struct
   let get_rpc_context node block =
     match block with
     | `Genesis ->
-        let net_state = Net_validator.net_state node.mainnet_validator in
-        Chain.genesis net_state >>= fun block ->
+        let chain_state = Chain_validator.chain_state node.mainchain_validator in
+        Chain.genesis chain_state >>= fun block ->
         rpc_context block >>= fun ctxt ->
         Lwt.return (Some ctxt)
     | ( `Head n | `Test_head n ) as block ->
         let validator = get_validator node block in
-        let net_state = Net_validator.net_state validator in
-        let net_db = Net_validator.net_db validator in
-        Chain.head net_state >>= fun head ->
-        predecessor net_db n head >>= fun block ->
+        let chain_state = Chain_validator.chain_state validator in
+        let chain_db = Chain_validator.chain_db validator in
+        Chain.head chain_state >>= fun head ->
+        predecessor chain_db n head >>= fun block ->
         rpc_context block >>= fun ctxt ->
         Lwt.return (Some ctxt)
     | `Hash hash-> begin
@@ -346,9 +346,9 @@ module RPC = struct
       end
     | ( `Prevalidation | `Test_prevalidation ) as block ->
         let validator = get_validator node block in
-        let pv = Net_validator.prevalidator validator in
-        let net_state = Net_validator.net_state validator in
-        Chain.head net_state >>= fun head ->
+        let pv = Chain_validator.prevalidator validator in
+        let chain_state = Chain_validator.chain_state validator in
+        Chain.head chain_state >>= fun head ->
         let head_header = State.Block.header head in
         let head_hash = State.Block.hash head in
         State.Block.context head >>= fun head_context ->
@@ -394,14 +394,14 @@ module RPC = struct
     | `Genesis -> Lwt.return []
     | ( `Head n | `Test_head n ) as block ->
         let validator = get_validator node block in
-        let net_state = Net_validator.net_state validator in
-        let net_db = Net_validator.net_db validator in
-        Chain.head net_state >>= fun head ->
-        predecessor net_db n head >>= fun block ->
+        let chain_state = Chain_validator.chain_state validator in
+        let chain_db = Chain_validator.chain_db validator in
+        Chain.head chain_state >>= fun head ->
+        predecessor chain_db n head >>= fun block ->
         State.Block.all_operation_hashes block
     | (`Prevalidation | `Test_prevalidation) as block ->
         let validator = get_validator node block in
-        let pv = Net_validator.prevalidator validator in
+        let pv = Chain_validator.prevalidator validator in
         let { Preapply_result.applied }, _ = Prevalidator.operations pv in
         Lwt.return [List.map fst applied]
     | `Hash hash ->
@@ -415,14 +415,14 @@ module RPC = struct
     | `Genesis -> Lwt.return []
     | ( `Head n | `Test_head n ) as block ->
         let validator = get_validator node block in
-        let net_state = Net_validator.net_state validator in
-        let net_db = Net_validator.net_db validator in
-        Chain.head net_state >>= fun head ->
-        predecessor net_db n head >>= fun block ->
+        let chain_state = Chain_validator.chain_state validator in
+        let chain_db = Chain_validator.chain_db validator in
+        Chain.head chain_state >>= fun head ->
+        predecessor chain_db n head >>= fun block ->
         State.Block.all_operations block
     | (`Prevalidation | `Test_prevalidation) as block ->
         let validator = get_validator node block in
-        let pv = Net_validator.prevalidator validator in
+        let pv = Chain_validator.prevalidator validator in
         let { Preapply_result.applied }, _ = Prevalidator.operations pv in
         Lwt.return [List.map snd applied]
     | `Hash hash ->
@@ -436,22 +436,22 @@ module RPC = struct
     | ( `Head 0 | `Prevalidation
       | `Test_head 0 | `Test_prevalidation ) as block ->
         let validator = get_validator node block in
-        let pv = Net_validator.prevalidator validator in
+        let pv = Chain_validator.prevalidator validator in
         Lwt.return (Prevalidator.operations pv)
     | ( `Head n | `Test_head n ) as block ->
         let validator = get_validator node block in
-        let prevalidator = Net_validator.prevalidator validator in
-        let net_state = Net_validator.net_state validator in
-        let net_db = Net_validator.net_db validator in
-        Chain.head net_state >>= fun head ->
-        predecessor net_db n head >>= fun b ->
+        let prevalidator = Chain_validator.prevalidator validator in
+        let chain_state = Chain_validator.chain_state validator in
+        let chain_db = Chain_validator.chain_db validator in
+        Chain.head chain_state >>= fun head ->
+        predecessor chain_db n head >>= fun b ->
         Prevalidator.pending ~block:b prevalidator >|= fun ops ->
         Preapply_result.empty, ops
     | `Genesis ->
-        let net_state = Net_validator.net_state node.mainnet_validator in
+        let chain_state = Chain_validator.chain_state node.mainchain_validator in
         let prevalidator =
-          Net_validator.prevalidator node.mainnet_validator in
-        Chain.genesis net_state >>= fun b ->
+          Chain_validator.prevalidator node.mainchain_validator in
+        Chain.genesis chain_state >>= fun b ->
         Prevalidator.pending ~block:b prevalidator >|= fun ops ->
         Preapply_result.empty, ops
     | `Hash h -> begin
@@ -459,9 +459,9 @@ module RPC = struct
         | None ->
             Lwt.return (Preapply_result.empty, Operation_hash.Map.empty)
         | Some validator ->
-            let net_state = Net_validator.net_state validator in
-            let prevalidator = Net_validator.prevalidator validator in
-            State.Block.read_exn net_state h >>= fun block ->
+            let chain_state = Chain_validator.chain_state validator in
+            let prevalidator = Chain_validator.prevalidator validator in
+            State.Block.read_exn chain_state h >>= fun block ->
             Prevalidator.pending ~block prevalidator >|= fun ops ->
             Preapply_result.empty, ops
       end
@@ -479,19 +479,19 @@ module RPC = struct
     begin
       match block with
       | `Genesis ->
-          let net_state = Net_validator.net_state node.mainnet_validator in
-          Chain.genesis net_state >>= return
+          let chain_state = Chain_validator.chain_state node.mainchain_validator in
+          Chain.genesis chain_state >>= return
       | ( `Head 0 | `Prevalidation
         | `Test_head 0 | `Test_prevalidation ) as block ->
           let validator = get_validator node block in
-          let net_state = Net_validator.net_state validator in
-          Chain.head net_state >>= return
+          let chain_state = Chain_validator.chain_state validator in
+          Chain.head chain_state >>= return
       | `Head n | `Test_head n as block -> begin
           let validator = get_validator node block in
-          let net_state = Net_validator.net_state validator in
-          let net_db = Net_validator.net_db validator in
-          Chain.head net_state >>= fun head ->
-          predecessor net_db n head >>= return
+          let chain_state = Chain_validator.chain_state validator in
+          let chain_db = Chain_validator.chain_db validator in
+          Chain.head chain_state >>= fun head ->
+          predecessor chain_db n head >>= return
         end
       | `Hash hash ->
           read_valid_block node hash >>= function
@@ -561,14 +561,14 @@ module RPC = struct
         Lwt.return (Some (RPC_directory.map (fun _ -> ()) dir))
 
   let heads node =
-    let net_state = Net_validator.net_state node.mainnet_validator in
-    Chain.known_heads net_state >>= fun heads ->
+    let chain_state = Chain_validator.chain_state node.mainchain_validator in
+    Chain.known_heads chain_state >>= fun heads ->
     begin
-      match Net_validator.child node.mainnet_validator with
+      match Chain_validator.child node.mainchain_validator with
       | None -> Lwt.return_nil
       | Some test_validator ->
-          let net_state = Net_validator.net_state test_validator in
-          Chain.known_heads net_state
+          let chain_state = Chain_validator.chain_state test_validator in
+          Chain.known_heads chain_state
     end >>= fun test_heads ->
     Lwt_list.fold_left_s
       (fun map block ->
@@ -625,10 +625,10 @@ module RPC = struct
     Lwt.return (List.rev blocks)
 
   let list_invalid node =
-    State.Block.list_invalid (Net_validator.net_state node.mainnet_validator)
+    State.Block.list_invalid (Chain_validator.chain_state node.mainchain_validator)
 
   let unmark_invalid node block =
-    State.Block.unmark_invalid (Net_validator.net_state node.mainnet_validator) block
+    State.Block.unmark_invalid (Chain_validator.chain_state node.mainchain_validator) block
 
   let block_header_watcher node =
     Distributed_db.watch_block_header node.distributed_db
@@ -646,13 +646,13 @@ module RPC = struct
 
   let bootstrapped node =
     let block_stream, stopper =
-      Net_validator.new_head_watcher node.mainnet_validator in
+      Chain_validator.new_head_watcher node.mainchain_validator in
     let first_run = ref true in
     let next () =
       if !first_run then begin
         first_run := false ;
-        let net_state = Net_validator.net_state node.mainnet_validator in
-        Chain.head net_state >>= fun head ->
+        let chain_state = Chain_validator.chain_state node.mainchain_validator in
+        Chain.head chain_state >>= fun head ->
         let head_hash = State.Block.hash head in
         let head_header = State.Block.header head in
         Lwt.return (Some (head_hash, head_header.shell.timestamp))
@@ -661,7 +661,7 @@ module RPC = struct
           ( Lwt_stream.get block_stream >|=
             Option.map ~f:(fun b ->
                 (State.Block.hash b, (State.Block.header b).shell.timestamp)) ) ;
-          (Net_validator.bootstrapped node.mainnet_validator >|= fun () -> None) ;
+          (Chain_validator.bootstrapped node.mainchain_validator >|= fun () -> None) ;
         ]
       end in
     let shutdown () = Lwt_watcher.shutdown stopper in
diff --git a/src/lib_shell/node.mli b/src/lib_shell/node.mli
index da3634a10..696588545 100644
--- a/src/lib_shell/node.mli
+++ b/src/lib_shell/node.mli
@@ -10,12 +10,12 @@
 type t
 
 type config = {
-  genesis: State.Net.genesis ;
+  genesis: State.Chain.genesis ;
   store_root: string ;
   context_root: string ;
   patch_context: (Context.t -> Context.t Lwt.t) option ;
   p2p: (P2p.config * P2p.limits) option ;
-  test_network_max_tll: int option ;
+  test_chain_max_tll: int option ;
 }
 
 and peer_validator_limits = {
@@ -34,7 +34,7 @@ and block_validator_limits = {
   protocol_timeout: float ;
   worker_limits : Worker_types.limits ;
 }
-and net_validator_limits = {
+and chain_validator_limits = {
   bootstrap_threshold: int ;
   worker_limits : Worker_types.limits ;
 }
@@ -44,7 +44,7 @@ val create:
   peer_validator_limits ->
   block_validator_limits ->
   prevalidator_limits ->
-  net_validator_limits ->
+  chain_validator_limits ->
   t tzresult Lwt.t
 
 module RPC : sig
@@ -53,7 +53,7 @@ module RPC : sig
   type block_info = Block_services.block_info
 
   val inject_block:
-    t -> ?force:bool -> ?net_id:Net_id.t ->
+    t -> ?force:bool -> ?chain_id:Chain_id.t ->
     MBytes.t -> Operation.t list list ->
     (Block_hash.t * unit tzresult Lwt.t) tzresult Lwt.t
   (** [inject_block node ?force bytes] tries to insert [bytes]
@@ -62,7 +62,7 @@ module RPC : sig
       non strictly increasing fitness. *)
 
   val inject_operation:
-    t -> ?net_id:Net_id.t -> MBytes.t ->
+    t -> ?chain_id:Chain_id.t -> MBytes.t ->
     (Operation_hash.t * unit tzresult Lwt.t) Lwt.t
   val inject_protocol:
     t -> ?force:bool -> Protocol.t ->
diff --git a/src/lib_shell/node_rpc.ml b/src/lib_shell/node_rpc.ml
index 3ee6dc51b..09b1dbf05 100644
--- a/src/lib_shell/node_rpc.ml
+++ b/src/lib_shell/node_rpc.ml
@@ -53,9 +53,9 @@ let register_bi_dir node dir =
   let dir =
     let implementation b () () =
       Node.RPC.block_info node b >>= fun bi ->
-      return bi.net_id in
+      return bi.chain_id in
     RPC_directory.register1 dir
-      Block_services.S.net_id implementation in
+      Block_services.S.chain_id implementation in
   let dir =
     let implementation b () () =
       Node.RPC.block_info node b >>= fun bi ->
@@ -96,9 +96,9 @@ let register_bi_dir node dir =
   let dir =
     let implementation b () () =
       Node.RPC.block_info node b >>= fun bi ->
-      return bi.test_network in
+      return bi.test_chain in
     RPC_directory.register1 dir
-      Block_services.S.test_network implementation in
+      Block_services.S.test_chain implementation in
   let dir =
     let implementation b () { Block_services.S.contents ; monitor } =
       match b with
@@ -408,9 +408,9 @@ let build_rpc_directory node =
       end in
     RPC_directory.register0 dir Shell_services.S.inject_block implementation in
   let dir =
-    let implementation () (contents, blocking, net_id) =
+    let implementation () (contents, blocking, chain_id) =
       Node.RPC.inject_operation
-        node ?net_id contents >>= fun (hash, wait) ->
+        node ?chain_id contents >>= fun (hash, wait) ->
       begin
         (if blocking then wait else return ()) >>=? fun () -> return hash
       end in
@@ -448,8 +448,8 @@ let build_rpc_directory node =
               (Prevalidator.running_workers ()))) in
   let dir  =
     RPC_directory.register1 dir Worker_services.Prevalidators.S.state
-      (fun net_id () () ->
-         let w = List.assoc net_id (Prevalidator.running_workers ()) in
+      (fun chain_id () () ->
+         let w = List.assoc chain_id (Prevalidator.running_workers ()) in
          return
            { Worker_types.status = Prevalidator.status w ;
              pending_requests = Prevalidator.pending_requests w ;
@@ -472,18 +472,18 @@ let build_rpc_directory node =
 
   let dir  =
     RPC_directory.register1 dir Worker_services.Peer_validators.S.list
-      (fun net_id () () ->
+      (fun chain_id () () ->
          return
            (List.filter_map
               (fun ((id, peer_id), w) ->
-                 if Net_id.equal id net_id then
+                 if Chain_id.equal id chain_id then
                    Some (peer_id, Peer_validator.status w)
                  else None)
               (Peer_validator.running_workers ()))) in
   let dir  =
     RPC_directory.register2 dir Worker_services.Peer_validators.S.state
-      (fun net_id peer_id () () ->
-         let w = List.assoc (net_id, peer_id) (Peer_validator.running_workers ()) in
+      (fun chain_id peer_id () () ->
+         let w = List.assoc (chain_id, peer_id) (Peer_validator.running_workers ()) in
          return
            { Worker_types.status = Peer_validator.status w ;
              pending_requests = [] ;
@@ -493,21 +493,21 @@ let build_rpc_directory node =
   (* Workers : Net validators *)
 
   let dir  =
-    RPC_directory.register0 dir Worker_services.Net_validators.S.list
+    RPC_directory.register0 dir Worker_services.Chain_validators.S.list
       (fun () () ->
          return
            (List.map
-              (fun (id, w) -> (id, Net_validator.status w))
-              (Net_validator.running_workers ()))) in
+              (fun (id, w) -> (id, Chain_validator.status w))
+              (Chain_validator.running_workers ()))) in
   let dir  =
-    RPC_directory.register1 dir Worker_services.Net_validators.S.state
-      (fun net_id () () ->
-         let w = List.assoc net_id (Net_validator.running_workers ()) in
+    RPC_directory.register1 dir Worker_services.Chain_validators.S.state
+      (fun chain_id () () ->
+         let w = List.assoc chain_id (Chain_validator.running_workers ()) in
          return
-           { Worker_types.status = Net_validator.status w ;
-             pending_requests = Net_validator.pending_requests w ;
-             backlog = Net_validator.last_events w ;
-             current_request = Net_validator.current_request w }) in
+           { Worker_types.status = Chain_validator.status w ;
+             pending_requests = Chain_validator.pending_requests w ;
+             backlog = Chain_validator.last_events w ;
+             current_request = Chain_validator.current_request w }) in
 
   (* Network  *)
   let dir = RPC_directory.merge dir (Node.RPC.build_p2p_rpc_directory node) in
diff --git a/src/lib_shell/peer_validator.ml b/src/lib_shell/peer_validator.ml
index a225cfb10..d8e007d72 100644
--- a/src/lib_shell/peer_validator.ml
+++ b/src/lib_shell/peer_validator.ml
@@ -12,13 +12,13 @@
 open Peer_validator_worker_state
 
 module Name = struct
-  type t = Net_id.t * P2p_peer.Id.t
+  type t = Chain_id.t * P2p_peer.Id.t
   let encoding =
-    Data_encoding.tup2 Net_id.encoding P2p_peer.Id.encoding
+    Data_encoding.tup2 Chain_id.encoding P2p_peer.Id.encoding
   let base = [ "peer_validator" ]
-  let pp ppf (net, peer) =
+  let pp ppf (chain, peer) =
     Format.fprintf ppf "%a:%a"
-      Net_id.pp_short net P2p_peer.Id.pp_short peer
+      Chain_id.pp_short chain P2p_peer.Id.pp_short peer
 end
 
 module Request = struct
@@ -47,9 +47,9 @@ module Types = struct
   include Worker_state
 
   type parameters = {
-    net_db: Distributed_db.net_db ;
+    chain_db: Distributed_db.chain_db ;
     block_validator: Block_validator.t ;
-    (* callback to net_validator *)
+    (* callback to chain_validator *)
     notify_new_block: State.Block.t -> unit ;
     notify_bootstrapped: unit -> unit ;
     notify_termination: unit -> unit ;
@@ -103,7 +103,7 @@ let bootstrap_new_branch w _ancestor _head unknown_prefix =
       ~block_header_timeout:pv.parameters.limits.block_header_timeout
       ~block_operations_timeout:pv.parameters.limits.block_operations_timeout
       pv.parameters.block_validator
-      pv.peer_id pv.parameters.net_db unknown_prefix in
+      pv.peer_id pv.parameters.chain_db unknown_prefix in
   Worker.protect w
     ~on_error:begin fun error ->
       (* if the peer_validator is killed, let's cancel the pipeline *)
@@ -121,14 +121,14 @@ let bootstrap_new_branch w _ancestor _head unknown_prefix =
 
 let validate_new_head w hash (header : Block_header.t) =
   let pv = Worker.state w in
-  let net_state = Distributed_db.net_state pv.parameters.net_db in
-  State.Block.known net_state header.shell.predecessor >>= function
+  let chain_state = Distributed_db.chain_state pv.parameters.chain_db in
+  State.Block.known chain_state header.shell.predecessor >>= function
   | false ->
       debug w
         "missing predecessor for new head %a from peer %a"
         Block_hash.pp_short hash
         P2p_peer.Id.pp_short pv.peer_id ;
-      Distributed_db.Request.current_branch pv.parameters.net_db ~peer:pv.peer_id () ;
+      Distributed_db.Request.current_branch pv.parameters.chain_db ~peer:pv.peer_id () ;
       return ()
   | true ->
       debug w
@@ -140,7 +140,7 @@ let validate_new_head w hash (header : Block_header.t) =
            Worker.protect w begin fun () ->
              Distributed_db.Operations.fetch
                ~timeout:pv.parameters.limits.block_operations_timeout
-               pv.parameters.net_db ~peer:pv.peer_id
+               pv.parameters.chain_db ~peer:pv.peer_id
                (hash, i) header.shell.operations_hash
            end)
         (0 -- (header.shell.validation_passes - 1)) >>=? fun operations ->
@@ -150,7 +150,7 @@ let validate_new_head w hash (header : Block_header.t) =
         P2p_peer.Id.pp_short pv.peer_id ;
       Block_validator.validate
         ~notify_new_block:pv.parameters.notify_new_block
-        pv.parameters.block_validator pv.parameters.net_db
+        pv.parameters.block_validator pv.parameters.chain_db
         hash header operations >>=? fun _block ->
       debug w
         "end of validation for new head %a from peer %a"
@@ -161,8 +161,8 @@ let validate_new_head w hash (header : Block_header.t) =
 
 let only_if_fitness_increases w distant_header cont =
   let pv = Worker.state w in
-  let net_state = Distributed_db.net_state pv.parameters.net_db in
-  Chain.head net_state >>= fun local_header ->
+  let chain_state = Distributed_db.chain_state pv.parameters.chain_db in
+  Chain.head chain_state >>= fun local_header ->
   if Fitness.compare
       distant_header.Block_header.shell.fitness
       (State.Block.fitness local_header) <= 0 then begin
@@ -177,10 +177,10 @@ let only_if_fitness_increases w distant_header cont =
 
 let may_validate_new_head w hash header =
   let pv = Worker.state w in
-  let net_state = Distributed_db.net_state pv.parameters.net_db in
-  State.Block.known net_state hash >>= function
+  let chain_state = Distributed_db.chain_state pv.parameters.chain_db in
+  State.Block.known chain_state hash >>= function
   | true -> begin
-      State.Block.known_valid net_state hash >>= function
+      State.Block.known_valid chain_state hash >>= function
       | true ->
           debug w
             "ignoring previously validated block %a from peer %a"
@@ -204,8 +204,8 @@ let may_validate_new_branch w distant_hash locator =
   let pv = Worker.state w in
   let distant_header, _ = (locator : Block_locator.t :> Block_header.t * _) in
   only_if_fitness_increases w distant_header @@ fun () ->
-  let net_state = Distributed_db.net_state pv.parameters.net_db in
-  Block_locator_iterator.known_ancestor net_state locator >>= function
+  let chain_state = Distributed_db.chain_state pv.parameters.chain_db in
+  Block_locator_iterator.known_ancestor chain_state locator >>= function
   | None ->
       debug w
         "ignoring branch %a without common ancestor from peer: %a."
@@ -220,7 +220,7 @@ let on_no_request w =
   debug w "no new head from peer %a for %g seconds."
     P2p_peer.Id.pp_short pv.peer_id
     pv.parameters.limits.new_head_request_timeout ;
-  Distributed_db.Request.current_head pv.parameters.net_db ~peer:pv.peer_id () ;
+  Distributed_db.Request.current_head pv.parameters.chain_db ~peer:pv.peer_id () ;
   return ()
 
 let on_request (type a) w (req : a Request.t) : a tzresult Lwt.t =
@@ -281,13 +281,13 @@ let on_error w r st errs =
 let on_close w =
   let pv = Worker.state w in
   pv.parameters.notify_termination () ;
-  Distributed_db.disconnect pv.parameters.net_db pv.peer_id >>= fun () ->
+  Distributed_db.disconnect pv.parameters.chain_db pv.peer_id >>= fun () ->
   Lwt.return ()
 
 let on_launch _ name parameters =
-  let net_state = Distributed_db.net_state parameters.net_db in
-  State.Block.read_exn net_state
-    (State.Net.genesis net_state).block >>= fun genesis ->
+  let chain_state = Distributed_db.chain_state parameters.chain_db in
+  State.Block.read_exn chain_state
+    (State.Chain.genesis chain_state).block >>= fun genesis ->
   let rec pv = {
     peer_id = snd name ;
     parameters = { parameters with notify_new_block } ;
@@ -324,10 +324,10 @@ let create
     ?(notify_new_block = fun _ -> ())
     ?(notify_bootstrapped = fun () -> ())
     ?(notify_termination = fun _ -> ())
-    limits block_validator net_db peer_id =
-  let name = (State.Net.id (Distributed_db.net_state net_db), peer_id) in
+    limits block_validator chain_db peer_id =
+  let name = (State.Chain.id (Distributed_db.chain_state chain_db), peer_id) in
   let parameters = {
-    net_db ;
+    chain_db ;
     notify_termination ;
     block_validator ;
     notify_new_block ;
diff --git a/src/lib_shell/peer_validator.mli b/src/lib_shell/peer_validator.mli
index 857e815e5..da4b7d721 100644
--- a/src/lib_shell/peer_validator.mli
+++ b/src/lib_shell/peer_validator.mli
@@ -27,13 +27,13 @@ val create:
   ?notify_termination: (unit -> unit) ->
   limits ->
   Block_validator.t ->
-  Distributed_db.net_db -> P2p_peer.Id.t -> t Lwt.t
+  Distributed_db.chain_db -> P2p_peer.Id.t -> t Lwt.t
 val shutdown: t -> unit Lwt.t
 
 val notify_branch: t -> Block_locator.t -> unit
 val notify_head: t -> Block_header.t -> unit
 
-val running_workers: unit -> ((Net_id.t * P2p_peer.Id.t) * t) list
+val running_workers: unit -> ((Chain_id.t * P2p_peer.Id.t) * t) list
 val status: t -> Worker_types.worker_status
 
 val current_request : t -> (Time.t * Time.t * Peer_validator_worker_state.Request.view) option
diff --git a/src/lib_shell/prevalidation.ml b/src/lib_shell/prevalidation.ml
index 870ede6cd..92fdec2cf 100644
--- a/src/lib_shell/prevalidation.ml
+++ b/src/lib_shell/prevalidation.ml
@@ -78,7 +78,7 @@ let start_prevalidation
     | Some protocol ->
         return protocol
   end >>=? fun (module Proto) ->
-  Context.reset_test_network
+  Context.reset_test_chain
     predecessor_context predecessor
     timestamp >>= fun predecessor_context ->
   Proto.begin_construction
diff --git a/src/lib_shell/prevalidator.ml b/src/lib_shell/prevalidator.ml
index a40c2eb39..932d7abd7 100644
--- a/src/lib_shell/prevalidator.ml
+++ b/src/lib_shell/prevalidator.ml
@@ -16,10 +16,10 @@ type limits = {
 }
 
 module Name = struct
-  type t = Net_id.t
-  let encoding = Net_id.encoding
+  type t = Chain_id.t
+  let encoding = Chain_id.encoding
   let base = [ "prevalidator" ]
-  let pp = Net_id.pp_short
+  let pp = Chain_id.pp_short
 end
 
 module Types = struct
@@ -30,7 +30,7 @@ module Types = struct
      - pv.prevalidation_result.refused = Ø, refused ops are in pv.refused
      - the 'applied' operations in pv.validation_result are in reverse order. *)
   type state = {
-    net_db : Distributed_db.net_db ;
+    chain_db : Distributed_db.chain_db ;
     limits : limits ;
     mutable predecessor : State.Block.t ;
     mutable timestamp : Time.t ;
@@ -46,7 +46,7 @@ module Types = struct
     mutable validation_state : Prevalidation.prevalidation_state tzresult ;
     mutable advertisement : [ `Pending of Mempool.t | `None ] ;
   }
-  type parameters = limits * Distributed_db.net_db
+  type parameters = limits * Distributed_db.chain_db
 
   include Worker_state
 
@@ -80,7 +80,7 @@ type error += Closed = Worker.Closed
 let debug w =
   Format.kasprintf (fun msg -> Worker.record_event w (Debug msg))
 
-let list_pendings ?maintain_net_db  ~from_block ~to_block old_mempool =
+let list_pendings ?maintain_chain_db  ~from_block ~to_block old_mempool =
   let rec pop_blocks ancestor block mempool =
     let hash = State.Block.hash block in
     if Block_hash.equal hash ancestor then
@@ -90,9 +90,9 @@ let list_pendings ?maintain_net_db  ~from_block ~to_block old_mempool =
       Lwt_list.fold_left_s
         (Lwt_list.fold_left_s (fun mempool op ->
              let h = Operation.hash op in
-             Lwt_utils.may maintain_net_db
-               ~f:begin fun net_db ->
-                 Distributed_db.inject_operation net_db h op >>= fun _ ->
+             Lwt_utils.may maintain_chain_db
+               ~f:begin fun chain_db ->
+                 Distributed_db.inject_operation chain_db h op >>= fun _ ->
                  Lwt.return_unit
                end >>= fun () ->
              Lwt.return (Operation_hash.Map.add h op mempool)))
@@ -103,10 +103,10 @@ let list_pendings ?maintain_net_db  ~from_block ~to_block old_mempool =
   in
   let push_block mempool block =
     State.Block.all_operation_hashes block >|= fun operations ->
-    Option.iter maintain_net_db
-      ~f:(fun net_db ->
+    Option.iter maintain_chain_db
+      ~f:(fun chain_db ->
           List.iter
-            (List.iter (Distributed_db.Operation.clear_or_cancel net_db))
+            (List.iter (Distributed_db.Operation.clear_or_cancel chain_db))
             operations) ;
     List.fold_left
       (List.fold_left (fun mempool h -> Operation_hash.Map.remove h mempool))
@@ -209,7 +209,7 @@ let handle_unprocessed w pv =
                    Operation_hash.Map.add h errs pv.refusals)
               pv.validation_result.refused ;
             Operation_hash.Map.iter
-              (fun oph _ -> Distributed_db.Operation.clear_or_cancel pv.net_db oph)
+              (fun oph _ -> Distributed_db.Operation.clear_or_cancel pv.chain_db oph)
               pv.validation_result.refused ;
             pv.validation_result <-
               merge_validation_results
@@ -232,7 +232,7 @@ let handle_unprocessed w pv =
           (fun k _ s -> Operation_hash.Set.add k s)
           pv.validation_result.branch_refused @@
         Operation_hash.Set.empty } ;
-  State.Current_mempool.set (Distributed_db.net_state pv.net_db)
+  State.Current_mempool.set (Distributed_db.chain_state pv.chain_db)
     ~head:(State.Block.hash pv.predecessor) pv.mempool >>= fun () ->
   Lwt.return ()
 
@@ -242,7 +242,7 @@ let fetch_operation w pv ?peer oph =
     Operation_hash.pp_short oph ;
   Distributed_db.Operation.fetch
     ~timeout:pv.limits.operation_timeout
-    pv.net_db ?peer oph () >>= function
+    pv.chain_db ?peer oph () >>= function
   | Ok op ->
       Worker.push_request_now w (Arrived (oph, op)) ;
       Lwt.return_unit
@@ -257,7 +257,7 @@ let fetch_operation w pv ?peer oph =
 let on_operation_arrived (pv : state) oph op =
   pv.fetching <- Operation_hash.Set.remove oph pv.fetching ;
   if not (Block_hash.Set.mem op.Operation.shell.branch pv.live_blocks) then begin
-    Distributed_db.Operation.clear_or_cancel pv.net_db oph
+    Distributed_db.Operation.clear_or_cancel pv.chain_db oph
     (* TODO: put in a specific delayed map ? *)
   end else if not (already_handled pv oph) (* prevent double inclusion on flush *) then begin
     pv.pending <- Operation_hash.Map.add oph op pv.pending
@@ -274,7 +274,7 @@ let on_inject pv op =
         validation_state ~sort:false [ (oph, op) ] >>= fun (_, result) ->
       match result.applied with
       | [ app_oph, _ ] when Operation_hash.equal app_oph oph ->
-          Distributed_db.inject_operation pv.net_db oph op >>= fun (_ : bool) ->
+          Distributed_db.inject_operation pv.chain_db oph op >>= fun (_ : bool) ->
           pv.pending <- Operation_hash.Map.add oph op pv.pending ;
           return result
       | _ ->
@@ -317,7 +317,7 @@ let on_notify w pv peer mempool =
 
 let on_flush w pv predecessor =
   list_pendings
-    ~maintain_net_db:pv.net_db
+    ~maintain_chain_db:pv.chain_db
     ~from_block:pv.predecessor ~to_block:predecessor
     (Preapply_result.operations pv.validation_result) >>= fun pending ->
   let timestamp = Time.now () in
@@ -352,7 +352,7 @@ let on_advertise pv =
   | `None -> () (* should not happen *)
   | `Pending mempool ->
       pv.advertisement <- `None ;
-      Distributed_db.Advertise.current_head pv.net_db ~mempool pv.predecessor
+      Distributed_db.Advertise.current_head pv.chain_db ~mempool pv.predecessor
 
 let on_request
   : type r. t -> r Request.t -> r tzresult Lwt.t
@@ -362,8 +362,8 @@ let on_request
       | Request.Flush hash ->
           on_advertise pv ;
           (* TODO: rebase the advertisement instead *)
-          let net_state = Distributed_db.net_state pv.net_db in
-          State.Block.read net_state hash >>=? fun block ->
+          let chain_state = Distributed_db.chain_state pv.chain_db in
+          State.Block.read chain_state hash >>=? fun block ->
           on_flush w pv block >>=? fun () ->
           return (() : r)
       | Request.Notify (peer, mempool) ->
@@ -385,16 +385,15 @@ let on_request
 let on_close w =
   let pv = Worker.state w in
   Operation_hash.Set.iter
-    (Distributed_db.Operation.clear_or_cancel pv.net_db)
+    (Distributed_db.Operation.clear_or_cancel pv.chain_db)
     pv.fetching ;
   Lwt.return_unit
 
-let on_launch w _ (limits, net_db) =
-  let net_state = Distributed_db.net_state net_db in
-  State.read_chain_store net_state
-    (fun _ { current_head ; current_mempool ; live_blocks ; live_operations } ->
-       Lwt.return (current_head, current_mempool, live_blocks, live_operations))
-  >>= fun (predecessor, mempool, live_blocks, live_operations) ->
+let on_launch w _ (limits, chain_db) =
+  let chain_state = Distributed_db.chain_state chain_db in
+  Chain.data chain_state >>= fun
+    { current_head = predecessor ; current_mempool = mempool ;
+      live_blocks ; live_operations } ->
   let timestamp = Time.now () in
   Prevalidation.start_prevalidation
     ~predecessor ~timestamp () >>= fun validation_state ->
@@ -411,7 +410,7 @@ let on_launch w _ (limits, net_db) =
       (fun s h -> Operation_hash.Set.add h s)
       Operation_hash.Set.empty mempool.known_valid in
   let pv =
-    { limits ; net_db ;
+    { limits ; chain_db ;
       predecessor ; timestamp ; live_blocks ; live_operations ;
       mempool = { known_valid = [] ; pending = Operation_hash.Set.empty };
       refused = Ring.create limits.max_refused_operations ;
@@ -436,8 +435,8 @@ let on_completion w r _ st =
 
 let table = Worker.create_table Queue
 
-let create limits net_db =
-  let net_state = Distributed_db.net_state net_db in
+let create limits chain_db =
+  let chain_state = Distributed_db.chain_state chain_db in
   let module Handlers = struct
     type self = t
     let on_launch = on_launch
@@ -448,8 +447,8 @@ let create limits net_db =
     let on_no_request _ = return ()
   end in
   Worker.launch table limits.worker_limits
-    (State.Net.id net_state)
-    (limits, net_db)
+    (State.Chain.id chain_state)
+    (limits, chain_db)
     (module Handlers)
 
 let shutdown = Worker.shutdown
@@ -472,7 +471,7 @@ let pending ?block w =
   match block with
   | Some to_block ->
       list_pendings
-        ~maintain_net_db:pv.net_db
+        ~maintain_chain_db:pv.chain_db
         ~from_block:pv.predecessor ~to_block ops
   | None -> Lwt.return ops
 
diff --git a/src/lib_shell/prevalidator.mli b/src/lib_shell/prevalidator.mli
index 956d35a23..4a4f141ed 100644
--- a/src/lib_shell/prevalidator.mli
+++ b/src/lib_shell/prevalidator.mli
@@ -36,9 +36,9 @@ type limits = {
   worker_limits : Worker_types.limits ;
 }
 
-type error += Closed of Net_id.t
+type error += Closed of Chain_id.t
 
-val create: limits -> Distributed_db.net_db -> t Lwt.t
+val create: limits -> Distributed_db.chain_db -> t Lwt.t
 val shutdown: t -> unit Lwt.t
 val notify_operations: t -> P2p_peer.Id.t -> Mempool.t -> unit
 val inject_operation: t -> Operation.t -> unit tzresult Lwt.t
@@ -48,7 +48,7 @@ val operations: t -> error Preapply_result.t * Operation.t Operation_hash.Map.t
 val context: t -> Updater.validation_result tzresult Lwt.t
 val pending: ?block:State.Block.t -> t -> Operation.t Operation_hash.Map.t Lwt.t
 
-val running_workers: unit -> (Net_id.t * t) list
+val running_workers: unit -> (Chain_id.t * t) list
 val status: t -> Worker_types.worker_status
 
 val pending_requests : t -> (Time.t * Prevalidator_worker_state.Request.view) list
diff --git a/src/lib_shell/protocol_validator.ml b/src/lib_shell/protocol_validator.ml
index 2bddd9181..5f26f5d53 100644
--- a/src/lib_shell/protocol_validator.ml
+++ b/src/lib_shell/protocol_validator.ml
@@ -181,7 +181,7 @@ let fetch_and_compile_protocols pv ?peer ?timeout (block: State.Block.t) =
     fetch_and_compile_protocol pv ?peer ?timeout protocol_hash >>=? fun _ ->
     return ()
   and test_protocol =
-    Context.get_test_network context >>= function
+    Context.get_test_chain context >>= function
     | Not_running -> return ()
     | Forking { protocol }
     | Running { protocol } ->
diff --git a/src/lib_shell/state.ml b/src/lib_shell/state.ml
index df556f436..7f795976b 100644
--- a/src/lib_shell/state.ml
+++ b/src/lib_shell/state.ml
@@ -10,7 +10,7 @@
 open Logging.Node.State
 
 type error +=
-  | Unknown_network of Net_id.t
+  | Unknown_chain of Chain_id.t
 
 type error += Bad_data_dir
 
@@ -20,14 +20,14 @@ let () =
   let open Error_monad in
   register_error_kind
     `Temporary
-    ~id:"state.unknown_network"
-    ~title:"Unknown network"
+    ~id:"state.unknown_chain"
+    ~title:"Unknown chain"
     ~description:"TODO"
     ~pp:(fun ppf id ->
-        Format.fprintf ppf "Unknown network %a" Net_id.pp id)
-    Data_encoding.(obj1 (req "net" Net_id.encoding))
-    (function Unknown_network x -> Some x | _ -> None)
-    (fun x -> Unknown_network x) ;
+        Format.fprintf ppf "Unknown chain %a" Chain_id.pp id)
+    Data_encoding.(obj1 (req "chain" Chain_id.encoding))
+    (function Unknown_chain x -> Some x | _ -> None)
+    (fun x -> Unknown_chain x) ;
   register_error_kind
     `Permanent
     ~id:"badDataDir"
@@ -70,22 +70,22 @@ type global_state = {
 }
 
 and global_data = {
-  nets: net_state Net_id.Table.t ;
+  chains: chain_state Chain_id.Table.t ;
   global_store: Store.t ;
   context_index: Context.index ;
 }
 
-and net_state = {
+and chain_state = {
   global_state: global_state ;
-  net_id: Net_id.t ;
+  chain_id: Chain_id.t ;
   genesis: genesis ;
   faked_genesis_hash: Block_hash.t ;
   expiration: Time.t option ;
-  allow_forked_network: bool ;
+  allow_forked_chain: bool ;
   block_store: Store.Block.store Shared.t ;
   context_index: Context.index Shared.t ;
   block_watcher: block Lwt_watcher.input ;
-  chain_state: chain_state Shared.t ;
+  chain_data: chain_data_state Shared.t ;
 }
 
 and genesis = {
@@ -94,9 +94,9 @@ and genesis = {
   protocol: Protocol_hash.t ;
 }
 
-and chain_state = {
+and chain_data_state = {
   mutable data: chain_data ;
-  chain_store: Store.Chain.store ;
+  chain_data_store: Store.Chain_data.store ;
 }
 
 and chain_data = {
@@ -108,24 +108,24 @@ and chain_data = {
 }
 
 and block = {
-  net_state: net_state ;
+  chain_state: chain_state ;
   hash: Block_hash.t ;
   contents: Store.Block.contents ;
 }
 
-let read_chain_store { chain_state } f =
-  Shared.use chain_state begin fun state ->
-    f state.chain_store state.data
+let read_chain_data { chain_data } f =
+  Shared.use chain_data begin fun state ->
+    f state.chain_data_store state.data
   end
 
-let update_chain_store { net_id ; context_index ; chain_state } f =
-  Shared.use chain_state begin fun state ->
-    f state.chain_store state.data >>= fun (data, res) ->
+let update_chain_data { chain_id ; context_index ; chain_data } f =
+  Shared.use chain_data begin fun state ->
+    f state.chain_data_store state.data >>= fun (data, res) ->
     Lwt_utils.may data
       ~f:begin fun data ->
         state.data <- data ;
         Shared.use context_index begin fun context_index ->
-          Context.set_head context_index net_id
+          Context.set_head context_index chain_id
             data.current_head.contents.context
         end >>= fun () ->
         Lwt.return_unit
@@ -232,15 +232,15 @@ let predecessor_n (store: Store.Block.store) (b: Block_hash.t) (distance: int)
     in
     loop b distance
 
-let compute_locator_from_hash (net : net_state) ?(size = 200) head_hash =
-  Shared.use net.block_store begin fun block_store ->
+let compute_locator_from_hash (chain : chain_state) ?(size = 200) head_hash =
+  Shared.use chain.block_store begin fun block_store ->
     Store.Block.Contents.read_exn (block_store, head_hash) >>= fun { header } ->
     Block_locator.compute ~predecessor:(predecessor_n block_store)
-      ~genesis:net.genesis.block head_hash header size
+      ~genesis:chain.genesis.block head_hash header size
   end
 
-let compute_locator net ?size head =
-  compute_locator_from_hash net ?size head.hash
+let compute_locator chain ?size head =
+  compute_locator_from_hash chain ?size head.hash
 
 type t = global_state
 
@@ -267,7 +267,7 @@ module Locked_block = struct
 
 end
 
-module Net = struct
+module Chain = struct
 
   type nonrec genesis = genesis = {
     time: Time.t ;
@@ -284,61 +284,61 @@ module Net = struct
          (req "block" Block_hash.encoding)
          (req "protocol" Protocol_hash.encoding))
 
-  type t = net_state
-  type net_state = t
+  type t = chain_state
+  type chain_state = t
 
   let allocate
-      ~genesis ~faked_genesis_hash ~expiration ~allow_forked_network
+      ~genesis ~faked_genesis_hash ~expiration ~allow_forked_chain
       ~current_head
-      global_state context_index chain_store block_store =
+      global_state context_index chain_data_store block_store =
     Store.Block.Contents.read_exn
       (block_store, current_head) >>= fun current_block ->
-    let rec chain_state = {
+    let rec chain_data = {
       data = {
         current_head = {
-          net_state ;
+          chain_state ;
           hash = current_head ;
           contents = current_block ;
         } ;
         current_mempool = Mempool.empty ;
         live_blocks = Block_hash.Set.singleton genesis.block ;
         live_operations = Operation_hash.Set.empty ;
-        locator = lazy (compute_locator_from_hash net_state current_head) ;
+        locator = lazy (compute_locator_from_hash chain_state current_head) ;
       } ;
-      chain_store ;
+      chain_data_store ;
     }
-    and net_state = {
+    and chain_state = {
       global_state ;
-      net_id = Net_id.of_block_hash genesis.block ;
-      chain_state = { Shared.data = chain_state ; lock = Lwt_mutex.create () } ;
+      chain_id = Chain_id.of_block_hash genesis.block ;
+      chain_data = { Shared.data = chain_data ; lock = Lwt_mutex.create () } ;
       genesis ; faked_genesis_hash ;
       expiration ;
-      allow_forked_network ;
+      allow_forked_chain ;
       block_store = Shared.create block_store ;
       context_index = Shared.create context_index ;
       block_watcher = Lwt_watcher.create_input () ;
     } in
-    Lwt.return net_state
+    Lwt.return chain_state
 
   let locked_create
-      global_state data ?expiration ?(allow_forked_network = false)
-      net_id genesis commit =
-    let net_store = Store.Net.get data.global_store net_id in
-    let block_store = Store.Block.get net_store
-    and chain_store = Store.Chain.get net_store in
-    Store.Net.Genesis_hash.store net_store genesis.block >>= fun () ->
-    Store.Net.Genesis_time.store net_store genesis.time >>= fun () ->
-    Store.Net.Genesis_protocol.store net_store genesis.protocol >>= fun () ->
-    Store.Chain.Current_head.store chain_store genesis.block >>= fun () ->
-    Store.Chain.Known_heads.store chain_store genesis.block >>= fun () ->
+      global_state data ?expiration ?(allow_forked_chain = false)
+      chain_id genesis commit =
+    let chain_store = Store.Chain.get data.global_store chain_id in
+    let block_store = Store.Block.get chain_store
+    and chain_data_store = Store.Chain_data.get chain_store in
+    Store.Chain.Genesis_hash.store chain_store genesis.block >>= fun () ->
+    Store.Chain.Genesis_time.store chain_store genesis.time >>= fun () ->
+    Store.Chain.Genesis_protocol.store chain_store genesis.protocol >>= fun () ->
+    Store.Chain_data.Current_head.store chain_data_store genesis.block >>= fun () ->
+    Store.Chain_data.Known_heads.store chain_data_store genesis.block >>= fun () ->
     begin
       match expiration with
       | None -> Lwt.return_unit
-      | Some time -> Store.Net.Expiration.store net_store time
+      | Some time -> Store.Chain.Expiration.store chain_store time
     end >>= fun () ->
     begin
-      if allow_forked_network then
-        Store.Net.Allow_forked_network.store data.global_store net_id
+      if allow_forked_chain then
+        Store.Chain.Allow_forked_chain.store data.global_store chain_id
       else
         Lwt.return_unit
     end >>= fun () ->
@@ -349,62 +349,62 @@ module Net = struct
       ~faked_genesis_hash:(Block_header.hash genesis_header)
       ~current_head:genesis.block
       ~expiration
-      ~allow_forked_network
+      ~allow_forked_chain
       global_state
       data.context_index
-      chain_store
+      chain_data_store
       block_store
 
-  let create state ?allow_forked_network genesis  =
-    let net_id = Net_id.of_block_hash genesis.block in
+  let create state ?allow_forked_chain genesis  =
+    let chain_id = Chain_id.of_block_hash genesis.block in
     Shared.use state.global_data begin fun data ->
-      if Net_id.Table.mem data.nets net_id then
-        Pervasives.failwith "State.Net.create"
+      if Chain_id.Table.mem data.chains chain_id then
+        Pervasives.failwith "State.Chain.create"
       else
         Context.commit_genesis
           data.context_index
-          ~net_id
+          ~chain_id
           ~time:genesis.time
           ~protocol:genesis.protocol >>= fun commit ->
         locked_create
-          state data ?allow_forked_network net_id genesis commit >>= fun net ->
-        Net_id.Table.add data.nets net_id net ;
-        Lwt.return net
+          state data ?allow_forked_chain chain_id genesis commit >>= fun chain ->
+        Chain_id.Table.add data.chains chain_id chain ;
+        Lwt.return chain
     end
 
   let locked_read global_state data id =
-    let net_store = Store.Net.get data.global_store id in
-    let block_store = Store.Block.get net_store
-    and chain_store = Store.Chain.get net_store in
-    Store.Net.Genesis_hash.read net_store >>=? fun genesis_hash ->
-    Store.Net.Genesis_time.read net_store >>=? fun time ->
-    Store.Net.Genesis_protocol.read net_store >>=? fun protocol ->
-    Store.Net.Expiration.read_opt net_store >>= fun expiration ->
-    Store.Net.Allow_forked_network.known
-      data.global_store id >>= fun allow_forked_network ->
+    let chain_store = Store.Chain.get data.global_store id in
+    let block_store = Store.Block.get chain_store
+    and chain_data_store = Store.Chain_data.get chain_store in
+    Store.Chain.Genesis_hash.read chain_store >>=? fun genesis_hash ->
+    Store.Chain.Genesis_time.read chain_store >>=? fun time ->
+    Store.Chain.Genesis_protocol.read chain_store >>=? fun protocol ->
+    Store.Chain.Expiration.read_opt chain_store >>= fun expiration ->
+    Store.Chain.Allow_forked_chain.known
+      data.global_store id >>= fun allow_forked_chain ->
     Store.Block.Contents.read (block_store, genesis_hash) >>=? fun genesis_header ->
     let genesis = { time ; protocol ; block = genesis_hash } in
-    Store.Chain.Current_head.read chain_store >>=? fun current_head ->
+    Store.Chain_data.Current_head.read chain_data_store >>=? fun current_head ->
     try
       allocate
         ~genesis
         ~faked_genesis_hash:(Block_header.hash genesis_header.header)
         ~current_head
         ~expiration
-        ~allow_forked_network
+        ~allow_forked_chain
         global_state
         data.context_index
-        chain_store
+        chain_data_store
         block_store >>= return
     with Not_found ->
       fail Bad_data_dir
 
   let locked_read_all global_state data =
-    Store.Net.list data.global_store >>= fun ids ->
+    Store.Chain.list data.global_store >>= fun ids ->
     iter_p
       (fun id ->
-         locked_read global_state data id >>=? fun net ->
-         Net_id.Table.add data.nets id net ;
+         locked_read global_state data id >>=? fun chain ->
+         Chain_id.Table.add data.chains id chain ;
          return ())
       ids
 
@@ -415,28 +415,28 @@ module Net = struct
 
   let get state id =
     Shared.use state.global_data begin fun data ->
-      try return (Net_id.Table.find data.nets id)
-      with Not_found -> fail (Unknown_network id)
+      try return (Chain_id.Table.find data.chains id)
+      with Not_found -> fail (Unknown_chain id)
     end
 
   let all state =
-    Shared.use state.global_data begin fun { nets } ->
+    Shared.use state.global_data begin fun { chains } ->
       Lwt.return @@
-      Net_id.Table.fold (fun _ net acc -> net :: acc) nets []
+      Chain_id.Table.fold (fun _ chain acc -> chain :: acc) chains []
     end
 
-  let id { net_id } = net_id
+  let id { chain_id } = chain_id
   let genesis { genesis } = genesis
   let faked_genesis_hash { faked_genesis_hash } = faked_genesis_hash
   let expiration { expiration } = expiration
-  let allow_forked_network { allow_forked_network } = allow_forked_network
+  let allow_forked_chain { allow_forked_chain } = allow_forked_chain
   let global_state { global_state } = global_state
 
-  let destroy state net =
-    lwt_debug "destroy %a" Net_id.pp (id net) >>= fun () ->
-    Shared.use state.global_data begin fun { global_store ; nets } ->
-      Net_id.Table.remove nets (id net) ;
-      Store.Net.destroy global_store (id net) >>= fun () ->
+  let destroy state chain =
+    lwt_debug "destroy %a" Chain_id.pp (id chain) >>= fun () ->
+    Shared.use state.global_data begin fun { global_store ; chains } ->
+      Chain_id.Table.remove chains (id chain) ;
+      Store.Chain.destroy global_store (id chain) >>= fun () ->
       Lwt.return_unit
     end
 
@@ -445,7 +445,7 @@ end
 module Block = struct
 
   type t = block = {
-    net_state: Net.t ;
+    chain_state: Chain.t ;
     hash: Block_hash.t ;
     contents: Store.Block.contents ;
   }
@@ -456,8 +456,8 @@ module Block = struct
 
   let hash { hash } = hash
   let header { contents = { header } } = header
-  let net_state { net_state } = net_state
-  let net_id { net_state = { net_id } } = net_id
+  let chain_state { chain_state } = chain_state
+  let chain_id { chain_state = { chain_id } } = chain_id
   let shell_header { contents = { header = { shell } } } = shell
   let timestamp b = (shell_header b).timestamp
   let fitness b = (shell_header b).fitness
@@ -470,36 +470,36 @@ module Block = struct
   let max_operation_data_length { contents = { max_operation_data_length } } =
     max_operation_data_length
 
-  let is_genesis b = Block_hash.equal b.hash b.net_state.genesis.block
+  let is_genesis b = Block_hash.equal b.hash b.chain_state.genesis.block
 
-  let known_valid net_state hash =
-    Shared.use net_state.block_store begin fun store ->
+  let known_valid chain_state hash =
+    Shared.use chain_state.block_store begin fun store ->
       Store.Block.Contents.known (store, hash)
     end
-  let known_invalid net_state hash =
-    Shared.use net_state.block_store begin fun store ->
+  let known_invalid chain_state hash =
+    Shared.use chain_state.block_store begin fun store ->
       Store.Block.Invalid_block.known store hash
     end
-  let read_invalid net_state hash =
-    Shared.use net_state.block_store begin fun store ->
+  let read_invalid chain_state hash =
+    Shared.use chain_state.block_store begin fun store ->
       Store.Block.Invalid_block.read_opt store hash
     end
-  let list_invalid net_state =
-    Shared.use net_state.block_store begin fun store ->
+  let list_invalid chain_state =
+    Shared.use chain_state.block_store begin fun store ->
       Store.Block.Invalid_block.fold store ~init:[]
         ~f:(fun hash { level ; errors } acc ->
             Lwt.return ((hash, level, errors) :: acc))
     end
-  let unmark_invalid net_state block =
-    Shared.use net_state.block_store begin fun store ->
+  let unmark_invalid chain_state block =
+    Shared.use chain_state.block_store begin fun store ->
       Store.Block.Invalid_block.known store block >>= fun mem ->
       if mem
       then Store.Block.Invalid_block.remove store block >>= return
       else fail (Block_not_invalid block)
     end
 
-  let known net_state hash =
-    Shared.use net_state.block_store begin fun store ->
+  let known chain_state hash =
+    Shared.use chain_state.block_store begin fun store ->
       Store.Block.Contents.known (store, hash) >>= fun known ->
       if known then
         Lwt.return_true
@@ -507,42 +507,42 @@ module Block = struct
         Store.Block.Invalid_block.known store hash
     end
 
-  let read net_state hash =
-    Shared.use net_state.block_store begin fun store ->
+  let read chain_state hash =
+    Shared.use chain_state.block_store begin fun store ->
       Store.Block.Contents.read (store, hash) >>=? fun contents ->
-      return { net_state ; hash ; contents }
+      return { chain_state ; hash ; contents }
     end
-  let read_opt net_state hash =
-    read net_state hash >>= function
+  let read_opt chain_state hash =
+    read chain_state hash >>= function
     | Error _ -> Lwt.return None
     | Ok v -> Lwt.return (Some v)
-  let read_exn net_state hash =
-    Shared.use net_state.block_store begin fun store ->
+  let read_exn chain_state hash =
+    Shared.use chain_state.block_store begin fun store ->
       Store.Block.Contents.read_exn (store, hash) >>= fun contents ->
-      Lwt.return { net_state ; hash ; contents }
+      Lwt.return { chain_state ; hash ; contents }
     end
 
   (* Quick accessor to be optimized ?? *)
-  let read_predecessor net_state hash =
-    read net_state hash >>=? fun { contents = { header } } ->
+  let read_predecessor chain_state hash =
+    read chain_state hash >>=? fun { contents = { header } } ->
     return header.shell.predecessor
-  let read_predecessor_opt net_state hash =
-    read_predecessor net_state hash >>= function
+  let read_predecessor_opt chain_state hash =
+    read_predecessor chain_state hash >>= function
     | Error _ -> Lwt.return None
     | Ok v -> Lwt.return (Some v)
-  let read_predecessor_exn net_state hash =
-    read_exn net_state hash >>= fun { contents = { header } } ->
+  let read_predecessor_exn chain_state hash =
+    read_exn chain_state hash >>= fun { contents = { header } } ->
     Lwt.return header.shell.predecessor
 
-  let predecessor { net_state ; contents = { header } ; hash } =
+  let predecessor { chain_state ; contents = { header } ; hash } =
     if Block_hash.equal hash header.shell.predecessor then
       Lwt.return_none           (* we are at genesis *)
     else
-      read_exn net_state header.shell.predecessor >>= fun block ->
+      read_exn chain_state header.shell.predecessor >>= fun block ->
       Lwt.return (Some block)
 
-  let predecessor_n (net: Net.t) (b: Block_hash.t) (distance: int) : Block_hash.t option Lwt.t =
-    Shared.use net.block_store (fun store ->
+  let predecessor_n (chain: Chain.t) (b: Block_hash.t) (distance: int) : Block_hash.t option Lwt.t =
+    Shared.use chain.block_store (fun store ->
         predecessor_n store b distance)
 
 
@@ -569,13 +569,13 @@ module Block = struct
 
   let store
       ?(dont_enforce_context_hash = false)
-      net_state block_header operations
+      chain_state block_header operations
       { Updater.context ; message ; max_operations_ttl ;
         max_operation_data_length } =
     let bytes = Block_header.to_bytes block_header in
     let hash = Block_header.hash_raw bytes in
     (* let's the validator check the consistency... of fitness, level, ... *)
-    Shared.use net_state.block_store begin fun store ->
+    Shared.use chain_state.block_store begin fun store ->
       Store.Block.Invalid_block.known store hash >>= fun known_invalid ->
       fail_when known_invalid (failure "Known invalid") >>=? fun () ->
       Store.Block.Contents.known (store, hash) >>= fun known ->
@@ -616,22 +616,22 @@ module Block = struct
         (* Store predecessors *)
         store_predecessors store hash >>= fun () ->
         (* Update the chain state. *)
-        Shared.use net_state.chain_state begin fun chain_state ->
-          let store = chain_state.chain_store in
+        Shared.use chain_state.chain_data begin fun chain_data ->
+          let store = chain_data.chain_data_store in
           let predecessor = block_header.shell.predecessor in
-          Store.Chain.Known_heads.remove store predecessor >>= fun () ->
-          Store.Chain.Known_heads.store store hash
+          Store.Chain_data.Known_heads.remove store predecessor >>= fun () ->
+          Store.Chain_data.Known_heads.store store hash
         end >>= fun () ->
-        let block = { net_state ; hash ; contents } in
-        Lwt_watcher.notify net_state.block_watcher block ;
+        let block = { chain_state ; hash ; contents } in
+        Lwt_watcher.notify chain_state.block_watcher block ;
         return (Some block)
       end
     end
 
-  let store_invalid net_state block_header errors =
+  let store_invalid chain_state block_header errors =
     let bytes = Block_header.to_bytes block_header in
     let hash = Block_header.hash_raw bytes in
-    Shared.use net_state.block_store begin fun store ->
+    Shared.use chain_state.block_store begin fun store ->
       Store.Block.Contents.known (store, hash) >>= fun known_valid ->
       fail_when known_valid (failure "Known valid") >>=? fun () ->
       Store.Block.Invalid_block.known store hash >>= fun known_invalid ->
@@ -643,46 +643,46 @@ module Block = struct
         return true
     end
 
-  let watcher net_state =
-    Lwt_watcher.create_stream net_state.block_watcher
+  let watcher chain_state =
+    Lwt_watcher.create_stream chain_state.block_watcher
 
-  let operation_hashes { net_state ; hash ; contents } i =
+  let operation_hashes { chain_state ; hash ; contents } i =
     if i < 0 || contents.header.shell.validation_passes <= i then
       invalid_arg "State.Block.operations" ;
-    Shared.use net_state.block_store begin fun store ->
+    Shared.use chain_state.block_store begin fun store ->
       Store.Block.Operation_hashes.read_exn (store, hash) i >>= fun hashes ->
       Store.Block.Operation_path.read_exn (store, hash) i >>= fun path ->
       Lwt.return (hashes, path)
     end
 
-  let all_operation_hashes { net_state ; hash ; contents } =
-    Shared.use net_state.block_store begin fun store ->
+  let all_operation_hashes { chain_state ; hash ; contents } =
+    Shared.use chain_state.block_store begin fun store ->
       Lwt_list.map_p
         (Store.Block.Operation_hashes.read_exn (store, hash))
         (0 -- (contents.header.shell.validation_passes - 1))
     end
 
-  let operations { net_state ; hash ; contents } i =
+  let operations { chain_state ; hash ; contents } i =
     if i < 0 || contents.header.shell.validation_passes <= i then
       invalid_arg "State.Block.operations" ;
-    Shared.use net_state.block_store begin fun store ->
+    Shared.use chain_state.block_store begin fun store ->
       Store.Block.Operation_path.read_exn (store, hash) i >>= fun path ->
       Store.Block.Operations.read_exn (store, hash) i >>= fun ops ->
       Lwt.return (ops, path)
     end
 
-  let all_operations { net_state ; hash ; contents } =
-    Shared.use net_state.block_store begin fun store ->
+  let all_operations { chain_state ; hash ; contents } =
+    Shared.use chain_state.block_store begin fun store ->
       Lwt_list.map_p
         (fun i -> Store.Block.Operations.read_exn (store, hash) i)
         (0 -- (contents.header.shell.validation_passes - 1))
     end
 
-  let context { net_state ; hash } =
-    Shared.use net_state.block_store begin fun block_store ->
+  let context { chain_state ; hash } =
+    Shared.use chain_state.block_store begin fun block_store ->
       Store.Block.Contents.read_exn (block_store, hash)
     end >>= fun { context = commit } ->
-    Shared.use net_state.context_index begin fun context_index ->
+    Shared.use chain_state.context_index begin fun context_index ->
       Context.checkout_exn context_index commit
     end
 
@@ -690,23 +690,23 @@ module Block = struct
     context block >>= fun context ->
     Context.get_protocol context
 
-  let test_network block =
+  let test_chain block =
     context block >>= fun context ->
-    Context.get_test_network context
+    Context.get_test_chain context
 
 end
 
 let read_block { global_data } hash =
-  Shared.use global_data begin fun { nets } ->
-    Net_id.Table.fold
-      (fun _net_id net_state acc ->
+  Shared.use global_data begin fun { chains } ->
+    Chain_id.Table.fold
+      (fun _chain_id chain_state acc ->
          acc >>= function
          | Some _ -> acc
          | None ->
-             Block.read_opt net_state hash >>= function
+             Block.read_opt chain_state hash >>= function
              | None -> acc
              | Some block -> Lwt.return (Some block))
-      nets
+      chains
       Lwt.return_none
   end
 
@@ -715,22 +715,22 @@ let read_block_exn t hash =
   | None -> Lwt.fail Not_found
   | Some b -> Lwt.return b
 
-let fork_testnet block protocol expiration =
-  Shared.use block.net_state.global_state.global_data begin fun data ->
+let fork_testchain block protocol expiration =
+  Shared.use block.chain_state.global_state.global_data begin fun data ->
     Block.context block >>= fun context ->
-    Context.set_test_network context Not_running >>= fun context ->
+    Context.set_test_chain context Not_running >>= fun context ->
     Context.set_protocol context protocol >>= fun context ->
-    Context.commit_test_network_genesis
+    Context.commit_test_chain_genesis
       data.context_index block.hash block.contents.header.shell.timestamp
-      context >>=? fun (net_id, genesis, commit) ->
+      context >>=? fun (chain_id, genesis, commit) ->
     let genesis = {
       block = genesis ;
       time = Time.add block.contents.header.shell.timestamp 1L ;
       protocol ;
     } in
-    Net.locked_create block.net_state.global_state data
-      net_id ~expiration genesis commit >>= fun net ->
-    return net
+    Chain.locked_create block.chain_state.global_state data
+      chain_id ~expiration genesis commit >>= fun chain ->
+    return chain
   end
 
 module Protocol = struct
@@ -801,8 +801,8 @@ end
 
 module Current_mempool = struct
 
-  let set net_state ~head mempool =
-    update_chain_store net_state begin fun _chain_store data ->
+  let set chain_state ~head mempool =
+    update_chain_data chain_state begin fun _chain_data_store data ->
       if Block_hash.equal head (Block.hash data.current_head) then
         Lwt.return (Some { data with current_mempool = mempool },
                     ())
@@ -810,8 +810,8 @@ module Current_mempool = struct
         Lwt.return (None, ())
     end
 
-  let get net_state =
-    read_chain_store net_state begin fun _chain_store data ->
+  let get chain_state =
+    read_chain_data chain_state begin fun _chain_data_store data ->
       Lwt.return (Block.header data.current_head, data.current_mempool)
     end
 
@@ -825,7 +825,7 @@ let read
   Store.init store_root >>=? fun global_store ->
   Context.init ?patch_context ~root:context_root >>= fun context_index ->
   let global_data = {
-    nets = Net_id.Table.create 17 ;
+    chains = Chain_id.Table.create 17 ;
     global_store ;
     context_index ;
   } in
@@ -833,7 +833,7 @@ let read
     global_data = Shared.create global_data ;
     protocol_store = Shared.create @@ Store.Protocol.get global_store ;
   } in
-  Net.read_all state >>=? fun () ->
+  Chain.read_all state >>=? fun () ->
   return state
 
 let close { global_data } =
diff --git a/src/lib_shell/state.mli b/src/lib_shell/state.mli
index cfee2f603..47a6c1be8 100644
--- a/src/lib_shell/state.mli
+++ b/src/lib_shell/state.mli
@@ -13,8 +13,8 @@
 
     - the index of validation contexts; and
     - the persistent state of the node:
-      - the blockchain and its alternate heads of a "network";
-      - the pool of pending operations of a "network". *)
+      - the blockchain and its alternate heads ;
+      - the pool of pending operations of a chain. *)
 
 type t
 type global_state = t
@@ -34,17 +34,17 @@ val close:
 (** {2 Errors} **************************************************************)
 
 type error +=
-  | Unknown_network of Net_id.t
+  | Unknown_chain of Chain_id.t
 
 
 (** {2 Network} ************************************************************)
 
-(** Data specific to a given network (e.g the mainnet or the current
-    test network).  *)
-module Net : sig
+(** Data specific to a given chain (e.g the main chain or the current
+    test chain).  *)
+module Chain : sig
 
   type t
-  type net_state = t
+  type chain_state = t
 
   (** The chain starts from a genesis block associated to a seed protocol *)
   type genesis = {
@@ -54,36 +54,36 @@ module Net : sig
   }
   val genesis_encoding: genesis Data_encoding.t
 
-  (** Initialize a network for a given [genesis]. By default,
-      the network does accept forking test network. When
-      [~allow_forked_network:true] is provided, test network are allowed. *)
+  (** Initialize a chain for a given [genesis]. By default,
+      the chain does accept forking test chain. When
+      [~allow_forked_chain:true] is provided, test chain are allowed. *)
   val create:
     global_state ->
-    ?allow_forked_network:bool ->
-    genesis -> net_state Lwt.t
+    ?allow_forked_chain:bool ->
+    genesis -> chain_state Lwt.t
 
-  (** Look up for a network by the hash of its genesis block. *)
-  val get: global_state -> Net_id.t -> net_state tzresult Lwt.t
+  (** Look up for a chain by the hash of its genesis block. *)
+  val get: global_state -> Chain_id.t -> chain_state tzresult Lwt.t
 
-  (** Returns all the known networks. *)
-  val all: global_state -> net_state list Lwt.t
+  (** Returns all the known chains. *)
+  val all: global_state -> chain_state list Lwt.t
 
-  (** Destroy a network: this completly removes from the local storage all
-      the data associated to the network (this includes blocks and
+  (** Destroy a chain: this completly removes from the local storage all
+      the data associated to the chain (this includes blocks and
       operations). *)
-  val destroy: global_state -> net_state -> unit Lwt.t
+  val destroy: global_state -> chain_state -> unit Lwt.t
 
   (** Various accessors. *)
-  val id: net_state -> Net_id.t
-  val genesis: net_state -> genesis
-  val global_state: net_state -> global_state
+  val id: chain_state -> Chain_id.t
+  val genesis: chain_state -> genesis
+  val global_state: chain_state -> global_state
 
   (** Hash of the faked block header of the genesis block. *)
-  val faked_genesis_hash: net_state -> Block_hash.t
+  val faked_genesis_hash: chain_state -> Block_hash.t
 
-  (** Return the expiration timestamp of a test netwowk. *)
-  val expiration: net_state -> Time.t option
-  val allow_forked_network: net_state -> bool
+  (** Return the expiration timestamp of a test chain. *)
+  val expiration: chain_state -> Time.t option
+  val allow_forked_chain: chain_state -> bool
 
 end
 
@@ -94,29 +94,29 @@ module Block : sig
   type t
   type block = t
 
-  val known: Net.t -> Block_hash.t -> bool Lwt.t
-  val known_valid: Net.t -> Block_hash.t -> bool Lwt.t
-  val known_invalid: Net.t -> Block_hash.t -> bool Lwt.t
-  val read_invalid: Net.t -> Block_hash.t -> Store.Block.invalid_block option Lwt.t
-  val list_invalid: Net.t -> (Block_hash.t * int32 * error list) list Lwt.t
-  val unmark_invalid: Net.t -> Block_hash.t -> unit tzresult Lwt.t
+  val known: Chain.t -> Block_hash.t -> bool Lwt.t
+  val known_valid: Chain.t -> Block_hash.t -> bool Lwt.t
+  val known_invalid: Chain.t -> Block_hash.t -> bool Lwt.t
+  val read_invalid: Chain.t -> Block_hash.t -> Store.Block.invalid_block option Lwt.t
+  val list_invalid: Chain.t -> (Block_hash.t * int32 * error list) list Lwt.t
+  val unmark_invalid: Chain.t -> Block_hash.t -> unit tzresult Lwt.t
 
-  val read: Net.t -> Block_hash.t -> block tzresult Lwt.t
-  val read_opt: Net.t -> Block_hash.t -> block option Lwt.t
-  val read_exn: Net.t -> Block_hash.t -> block Lwt.t
+  val read: Chain.t -> Block_hash.t -> block tzresult Lwt.t
+  val read_opt: Chain.t -> Block_hash.t -> block option Lwt.t
+  val read_exn: Chain.t -> Block_hash.t -> block Lwt.t
 
   type error += Inconsistent_hash of Context_hash.t * Context_hash.t
 
   val store:
     ?dont_enforce_context_hash:bool ->
-    Net.t ->
+    Chain.t ->
     Block_header.t ->
     Operation.t list list ->
     Updater.validation_result ->
     block option tzresult Lwt.t
 
   val store_invalid:
-    Net.t ->
+    Chain.t ->
     Block_header.t ->
     error list ->
     bool tzresult Lwt.t
@@ -130,8 +130,8 @@ module Block : sig
   val timestamp: t -> Time.t
   val fitness: t -> Fitness.t
   val validation_passes: t -> int
-  val net_id: t -> Net_id.t
-  val net_state: t -> Net.t
+  val chain_id: t -> Chain_id.t
+  val chain_state: t -> Chain.t
   val level: t -> Int32.t
   val message: t -> string option
   val max_operations_ttl: t -> int
@@ -139,11 +139,11 @@ module Block : sig
 
   val is_genesis: t -> bool
   val predecessor: t -> block option Lwt.t
-  val predecessor_n: Net.t -> Block_hash.t -> int -> Block_hash.t option Lwt.t
+  val predecessor_n: Chain.t -> Block_hash.t -> int -> Block_hash.t option Lwt.t
 
   val context: t -> Context.t Lwt.t
   val protocol_hash: t -> Protocol_hash.t Lwt.t
-  val test_network: t -> Test_network_status.t Lwt.t
+  val test_chain: t -> Test_chain_status.t Lwt.t
 
   val operation_hashes:
     t -> int ->
@@ -154,7 +154,7 @@ module Block : sig
     t -> int -> (Operation.t list * Operation_list_list_hash.path) Lwt.t
   val all_operations: t -> Operation.t list list Lwt.t
 
-  val watcher: Net.t -> block Lwt_stream.t * Lwt_watcher.stopper
+  val watcher: Chain.t -> block Lwt_stream.t * Lwt_watcher.stopper
 
 end
 
@@ -164,10 +164,10 @@ val read_block:
 val read_block_exn:
   global_state -> Block_hash.t -> Block.t Lwt.t
 
-val compute_locator: Net.t -> ?size:int -> Block.t -> Block_locator.t Lwt.t
+val compute_locator: Chain.t -> ?size:int -> Block.t -> Block_locator.t Lwt.t
 
-val fork_testnet:
-  Block.t -> Protocol_hash.t -> Time.t -> Net.t tzresult Lwt.t
+val fork_testchain:
+  Block.t -> Protocol_hash.t -> Time.t -> Chain.t tzresult Lwt.t
 
 type chain_data = {
   current_head: Block.t ;
@@ -177,14 +177,14 @@ type chain_data = {
   locator: Block_locator.t Lwt.t lazy_t ;
 }
 
-val read_chain_store:
-  Net.t ->
-  (Store.Chain.store -> chain_data -> 'a Lwt.t) ->
+val read_chain_data:
+  Chain.t ->
+  (Store.Chain_data.store -> chain_data -> 'a Lwt.t) ->
   'a Lwt.t
 
-val update_chain_store:
-  Net.t ->
-  (Store.Chain.store -> chain_data -> (chain_data option * 'a) Lwt.t) ->
+val update_chain_data:
+  Chain.t ->
+  (Store.Chain_data.store -> chain_data -> (chain_data option * 'a) Lwt.t) ->
   'a Lwt.t
 
 (** {2 Protocol database} ***************************************************)
@@ -217,10 +217,10 @@ end
 
 module Current_mempool : sig
 
-  val get: Net.t -> (Block_header.t * Mempool.t) Lwt.t
+  val get: Chain.t -> (Block_header.t * Mempool.t) Lwt.t
   (** The current mempool. *)
 
-  val set: Net.t -> head:Block_hash.t -> Mempool.t -> unit Lwt.t
+  val set: Chain.t -> head:Block_hash.t -> Mempool.t -> unit Lwt.t
   (** Set the current mempool. It is ignored if the current head is
       not the provided one. *)
 
diff --git a/src/lib_storage/store.ml b/src/lib_shell/store.ml
similarity index 91%
rename from src/lib_storage/store.ml
rename to src/lib_shell/store.ml
index 5111f6862..a23284597 100644
--- a/src/lib_storage/store.ml
+++ b/src/lib_shell/store.ml
@@ -11,18 +11,18 @@ type t = Raw_store.t
 type global_store = t
 
 (**************************************************************************
- * Net store under "net/"
+ * Net store under "chain/"
  **************************************************************************)
 
-module Net = struct
+module Chain = struct
 
-  type store = global_store * Net_id.t
+  type store = global_store * Chain_id.t
   let get s id = (s, id)
 
   module Indexed_store =
     Store_helpers.Make_indexed_substore
-      (Store_helpers.Make_substore(Raw_store)(struct let name = ["net"] end))
-      (Net_id)
+      (Store_helpers.Make_substore(Raw_store)(struct let name = ["chain"] end))
+      (Chain_id)
 
   let destroy = Indexed_store.remove_all
   let list t =
@@ -59,24 +59,24 @@ module Net = struct
       (struct let name = ["expiration"] end)
       (Store_helpers.Make_value(Time))
 
-  module Allow_forked_network =
-    Indexed_store.Make_set (struct let name = ["allow_forked_network"] end)
+  module Allow_forked_chain =
+    Indexed_store.Make_set (struct let name = ["allow_forked_chain"] end)
 
 end
 
 (**************************************************************************
- * Block_header store under "net/<id>/blocks/"
+ * Block_header store under "chain/<id>/blocks/"
  **************************************************************************)
 
 module Block = struct
 
-  type store = Net.store
+  type store = Chain.store
   let get x = x
 
   module Indexed_store =
     Store_helpers.Make_indexed_substore
       (Store_helpers.Make_substore
-         (Net.Indexed_store.Store)
+         (Chain.Indexed_store.Store)
          (struct let name = ["blocks"] end))
       (Block_hash)
 
@@ -153,7 +153,7 @@ module Block = struct
   module Invalid_block =
     Store_helpers.Make_map
       (Store_helpers.Make_substore
-         (Net.Indexed_store.Store)
+         (Chain.Indexed_store.Store)
          (struct let name = ["invalid_blocks"] end))
       (Block_hash)
       (Store_helpers.Make_value(struct
@@ -169,9 +169,9 @@ module Block = struct
   let register s =
     Base58.register_resolver Block_hash.b58check_encoding begin fun str ->
       let pstr = Block_hash.prefix_path str in
-      Net.Indexed_store.fold_indexes s ~init:[]
-        ~f:begin fun net acc ->
-          Indexed_store.resolve_index (s, net) pstr >>= fun l ->
+      Chain.Indexed_store.fold_indexes s ~init:[]
+        ~f:begin fun chain acc ->
+          Indexed_store.resolve_index (s, chain) pstr >>= fun l ->
           Lwt.return (List.rev_append l acc)
         end
     end
@@ -191,26 +191,26 @@ end
  * Blockchain data
  **************************************************************************)
 
-module Chain = struct
+module Chain_data = struct
 
-  type store = Net.store
+  type store = Chain.store
   let get s = s
 
   module Known_heads =
     Store_helpers.Make_buffered_set
       (Store_helpers.Make_substore
-         (Net.Indexed_store.Store)
+         (Chain.Indexed_store.Store)
          (struct let name = ["known_heads"] end))
       (Block_hash)
       (Block_hash.Set)
 
   module Current_head =
     Store_helpers.Make_single_store
-      (Net.Indexed_store.Store)
+      (Chain.Indexed_store.Store)
       (struct let name = ["current_head"] end)
       (Store_helpers.Make_value(Block_hash))
 
-  module In_chain =
+  module In_main_branch =
     Store_helpers.Make_single_store
       (Block.Indexed_store.Store)
       (struct let name = ["in_chain"] end)
diff --git a/src/lib_storage/store.mli b/src/lib_shell/store.mli
similarity index 87%
rename from src/lib_storage/store.mli
rename to src/lib_shell/store.mli
index c88a1d8b2..dafee7327 100644
--- a/src/lib_storage/store.mli
+++ b/src/lib_shell/store.mli
@@ -17,15 +17,15 @@ val init: string -> t tzresult Lwt.t
 val close : t -> unit
 
 
-(** {2 Net store} ************************************************************)
+(** {2 Chain store} **********************************************************)
 
-module Net : sig
+module Chain : sig
 
-  val list: global_store -> Net_id.t list Lwt.t
-  val destroy: global_store -> Net_id.t -> unit Lwt.t
+  val list: global_store -> Chain_id.t list Lwt.t
+  val destroy: global_store -> Chain_id.t -> unit Lwt.t
 
   type store
-  val get: global_store -> Net_id.t -> store
+  val get: global_store -> Chain_id.t -> store
 
   module Genesis_hash : SINGLE_STORE
     with type t := store
@@ -47,19 +47,19 @@ module Net : sig
     with type t := store
      and type value := Time.t
 
-  module Allow_forked_network : SET_STORE
+  module Allow_forked_chain : SET_STORE
     with type t := t
-     and type elt := Net_id.t
+     and type elt := Chain_id.t
 
 end
 
 
-(** {2 Chain data} ***********************************************************)
+(** {2 Mutable chain data} *******************************************************)
 
-module Chain : sig
+module Chain_data : sig
 
   type store
-  val get: Net.store -> store
+  val get: Chain.store -> store
 
   module Current_head : SINGLE_STORE
     with type t := store
@@ -70,7 +70,7 @@ module Chain : sig
      and type elt := Block_hash.t
      and module Set := Block_hash.Set
 
-  module In_chain : SINGLE_STORE
+  module In_main_branch : SINGLE_STORE
     with type t = store * Block_hash.t
      and type value := Block_hash.t (* successor *)
 
@@ -82,7 +82,7 @@ end
 module Block : sig
 
   type store
-  val get: Net.store -> store
+  val get: Chain.store -> store
 
   type contents = {
     header: Block_header.t ;
diff --git a/src/lib_shell/test/assert.ml b/src/lib_shell/test/assert.ml
index f360752c0..319b2e2dc 100644
--- a/src/lib_shell/test/assert.ml
+++ b/src/lib_shell/test/assert.ml
@@ -39,3 +39,55 @@ let equal_block ?msg st1 st2 =
     | None -> "none"
     | Some st -> Block_hash.to_hex (Block_header.hash st) in
   equal ?msg ~prn ~eq st1 st2
+
+let make_equal_list eq prn ?(msg="") x y =
+  let rec iter i x y =
+    match x, y with
+    | hd_x :: tl_x, hd_y :: tl_y ->
+        if eq hd_x hd_y then
+          iter (succ i) tl_x tl_y
+        else
+          let fm = Printf.sprintf "%s (at index %d)" msg i in
+          fail (prn hd_x) (prn hd_y) fm
+    | _ :: _, [] | [], _ :: _ ->
+        let fm = Printf.sprintf "%s (lists of different sizes)" msg in
+        fail_msg "%s" fm
+    | [], [] ->
+        () in
+  iter 0 x y
+
+let equal_string_list ?msg l1 l2 =
+  make_equal_list ?msg (=) (fun x -> x) l1 l2
+
+let equal_string_list_list ?msg l1 l2 =
+  let pr_persist l =
+    let res =
+      String.concat ";" (List.map (fun s -> Printf.sprintf "%S" s) l) in
+    Printf.sprintf "[%s]" res in
+  make_equal_list ?msg (=) pr_persist l1 l2
+
+let equal_block_set ?msg set1 set2 =
+  let b1 = Block_hash.Set.elements set1
+  and b2 = Block_hash.Set.elements set2 in
+  make_equal_list ?msg
+    (fun h1 h2 -> Block_hash.equal h1 h2)
+    Block_hash.to_string
+    b1 b2
+
+let equal_block_map ?msg ~eq map1 map2 =
+  let b1 = Block_hash.Map.bindings map1
+  and b2 = Block_hash.Map.bindings map2 in
+  make_equal_list ?msg
+    (fun (h1, b1) (h2, b2) -> Block_hash.equal h1 h2 && eq b1 b2)
+    (fun (h1, _) -> Block_hash.to_string h1)
+    b1 b2
+
+let equal_block_hash_list ?msg l1 l2 =
+  let pr_block_hash = Block_hash.to_short_b58check in
+  make_equal_list ?msg Block_hash.equal pr_block_hash l1 l2
+
+let is_false ?(msg="") x =
+  if x then fail "false" "true" msg
+
+let is_true ?(msg="") x =
+  if not x then fail "true" "false" msg
diff --git a/src/lib_shell/test/jbuild b/src/lib_shell/test/jbuild
index 5a224d8eb..dbcc8bd07 100644
--- a/src/lib_shell/test/jbuild
+++ b/src/lib_shell/test/jbuild
@@ -1,7 +1,7 @@
 (jbuild_version 1)
 
 (executables
- ((names (test_state
+ ((names (test
           test_locator))
   (libraries (tezos-base
               tezos-storage
@@ -20,12 +20,12 @@
 
 (alias
  ((name buildtest)
-  (deps (test_state.exe
+  (deps (test.exe
          test_locator.exe))))
 
 (alias
- ((name runtest_state)
-  (action (run ${exe:test_state.exe}))))
+ ((name runtest_shell)
+  (action (run ${exe:test.exe}))))
 
 (alias
  ((name runtest_locator)
@@ -37,7 +37,7 @@
 
 (alias
  ((name runtest)
-  (deps ((alias runtest_state)
+  (deps ((alias runtest_shell)
          (alias runtest_locator)))))
 
 (alias
diff --git a/src/lib_shell/test/test.ml b/src/lib_shell/test/test.ml
new file mode 100644
index 000000000..8dbf0408b
--- /dev/null
+++ b/src/lib_shell/test/test.ml
@@ -0,0 +1,14 @@
+(**************************************************************************)
+(*                                                                        *)
+(*    Copyright (c) 2014 - 2018.                                          *)
+(*    Dynamic Ledger Solutions, Inc. <contact@tezos.com>                  *)
+(*                                                                        *)
+(*    All rights reserved. No warranty, explicit or implicit, provided.   *)
+(*                                                                        *)
+(**************************************************************************)
+
+let () =
+  Alcotest.run "tezos-state" [
+    "store", Test_store.tests ;
+    "state", Test_state.tests ;
+  ]
diff --git a/src/lib_shell/test/test_locator.ml b/src/lib_shell/test/test_locator.ml
index 57c25623a..b4083459a 100644
--- a/src/lib_shell/test/test_locator.ml
+++ b/src/lib_shell/test/test_locator.ml
@@ -23,12 +23,12 @@ let genesis_time = Time.of_seconds 0L
 
 let state_genesis_block =
   {
-    State.Net.time = genesis_time;
-    State.Net.block= genesis_hash;
-    State.Net.protocol = genesis_protocol
+    State.Chain.time = genesis_time;
+    State.Chain.block= genesis_hash;
+    State.Chain.protocol = genesis_protocol
   }
 
-let net_id = Net_id.of_block_hash genesis_hash
+let chain_id = Chain_id.of_block_hash genesis_hash
 
 module Proto = (val Registred_protocol.get_exn genesis_protocol)
 
@@ -51,13 +51,13 @@ let incr_fitness fitness =
 
 
 (* returns a new state with a single block, genesis *)
-let init_net base_dir : State.Net.t Lwt.t =
+let init_chain base_dir : State.Chain.t Lwt.t =
   let store_root = base_dir // "store" in
   let context_root = base_dir // "context" in
   State.read ~store_root ~context_root () >>= function
   | Error _ -> Pervasives.failwith "read err"
   | Ok (state:State.global_state) ->
-      State.Net.create state state_genesis_block
+      State.Chain.create state state_genesis_block
 
 
 let block_header
@@ -81,9 +81,9 @@ let block_header
     Block_header.proto = MBytes.of_string "" ;
   }
 
-(* adds n blocks on top of an initialized net *)
-let make_empty_chain (net:State.Net.t) n : Block_hash.t Lwt.t =
-  State.Block.read_exn net genesis_hash >>= fun genesis ->
+(* adds n blocks on top of an initialized chain *)
+let make_empty_chain (chain:State.Chain.t) n : Block_hash.t Lwt.t =
+  State.Block.read_exn chain genesis_hash >>= fun genesis ->
   State.Block.context genesis >>= fun empty_context ->
   let header = State.Block.header genesis in
   Context.commit
@@ -104,7 +104,7 @@ let make_empty_chain (net:State.Net.t) n : Block_hash.t Lwt.t =
         { header with
           shell = { header.shell with predecessor = pred ;
                                       level = Int32.of_int lvl } } in
-      State.Block.store net header [] empty_result >>=? fun _ ->
+      State.Block.store chain header [] empty_result >>=? fun _ ->
       loop (lvl+1) (Block_header.hash header)
   in
   loop 1 genesis_hash >>= function
@@ -151,22 +151,22 @@ let print_block b =
     (Int32.to_int (State.Block.level b))
     (Block_hash.to_b58check (State.Block.hash b))
 
-let print_block_h net bh =
-  State.Block.read_exn net bh >|= fun b ->
+let print_block_h chain bh =
+  State.Block.read_exn chain bh >|= fun b ->
   print_block b
 
 
 (* returns the predecessor at distance one, reading the header *)
-let linear_predecessor net (bh: Block_hash.t) : Block_hash.t option Lwt.t =
-  State.Block.read_exn net bh >>= fun b ->
+let linear_predecessor chain (bh: Block_hash.t) : Block_hash.t option Lwt.t =
+  State.Block.read_exn chain bh >>= fun b ->
   State.Block.predecessor b >|= function
   | None -> None
   | Some pred -> Some (State.Block.hash pred)
 
-let print_chain net bh =
+let print_chain chain bh =
   let rec loop bh cnt =
-    let _ = print_block_h net bh in
-    linear_predecessor net bh >>= function
+    let _ = print_block_h chain bh in
+    linear_predecessor chain bh >>= function
     | Some pred -> loop pred (cnt+1)
     | None -> Lwt.return_unit
   in
@@ -174,15 +174,15 @@ let print_chain net bh =
 
 
 (* returns the predecessors at ditance n, traversing all n intermediate blocks *)
-let linear_predecessor_n (net:State.Net.t) (bh:Block_hash.t) (distance:int)
+let linear_predecessor_n (chain:State.Chain.t) (bh:Block_hash.t) (distance:int)
   : Block_hash.t option Lwt.t =
-  (* let _ = Printf.printf "LP: %4i " distance; print_block_h net bh in *)
+  (* let _ = Printf.printf "LP: %4i " distance; print_block_h chain bh in *)
   if distance < 1 then invalid_arg "distance<1" else
     let rec loop bh distance =
       if distance = 0
       then Lwt.return_some bh   (* reached distance *)
       else
-        linear_predecessor net bh >>= function
+        linear_predecessor chain bh >>= function
         | None -> Lwt.return_none
         | Some pred ->
             loop pred (distance-1)
@@ -197,12 +197,12 @@ let linear_predecessor_n (net:State.Net.t) (bh:Block_hash.t) (distance:int)
    requested *)
 let test_pred (base_dir:string) : unit tzresult Lwt.t =
   let size_chain = 1000 in
-  init_net base_dir >>= fun net ->
-  make_empty_chain net size_chain >>= fun head ->
+  init_chain base_dir >>= fun chain ->
+  make_empty_chain chain size_chain >>= fun head ->
 
   let test_once distance =
-    linear_predecessor_n net head distance >>= fun lin_res ->
-    State.Block.predecessor_n net head distance >>= fun exp_res ->
+    linear_predecessor_n chain head distance >>= fun lin_res ->
+    State.Block.predecessor_n chain head distance >>= fun exp_res ->
     match lin_res,exp_res with
     | None, None ->
         Lwt.return_unit
@@ -211,9 +211,9 @@ let test_pred (base_dir:string) : unit tzresult Lwt.t =
     | Some lin_res, Some exp_res ->
         (* check that the two results are the same *)
         (assert (lin_res = exp_res));
-        State.Block.read_exn net lin_res >>= fun pred ->
+        State.Block.read_exn chain lin_res >>= fun pred ->
         let level_pred = Int32.to_int (State.Block.level pred) in
-        State.Block.read_exn net head >>= fun head ->
+        State.Block.read_exn chain head >>= fun head ->
         let level_start = Int32.to_int (State.Block.level head) in
         (* check distance using the level *)
         assert (level_start - distance = level_pred);
@@ -226,11 +226,11 @@ let test_pred (base_dir:string) : unit tzresult Lwt.t =
 
 
 (* compute locator using the linear predecessor *)
-let compute_linear_locator (net:State.Net.t) ~size block =
-  let genesis = State.Net.genesis net in
+let compute_linear_locator (chain:State.Chain.t) ~size block =
+  let genesis = State.Chain.genesis chain in
   let block_hash = State.Block.hash block in
   let header = State.Block.header block in
-  Block_locator.compute ~predecessor:(linear_predecessor_n net)
+  Block_locator.compute ~predecessor:(linear_predecessor_n chain)
     ~genesis:genesis.block block_hash header size
 
 
@@ -270,9 +270,9 @@ let test_locator base_dir =
   let locator_limit = compute_size_locator size_chain in
   let _ = Printf.printf "#locator_limit %i\n" locator_limit in
 
-  init_net base_dir >>= fun net ->
+  init_chain base_dir >>= fun chain ->
   time1 (fun () ->
-      make_empty_chain net size_chain) |>
+      make_empty_chain chain size_chain) |>
   fun (res, t_chain) ->
   let _ = Printf.printf
       "#size_chain %i built in %f sec\n#      size      exp       lins\n"
@@ -280,12 +280,12 @@ let test_locator base_dir =
   res >>= fun head ->
 
   let check_locator size : unit tzresult Lwt.t =
-    State.Block.read net head >>=? fun block ->
+    State.Block.read chain head >>=? fun block ->
     time ~runs:runs (fun () ->
-        State.compute_locator net ~size:size block) |>
+        State.compute_locator chain ~size:size block) |>
     fun (l_exp,t_exp) ->
     time ~runs:runs (fun () ->
-        compute_linear_locator net ~size:size block) |>
+        compute_linear_locator chain ~size:size block) |>
     fun (l_lin,t_lin) ->
     l_exp >>= fun l_exp ->
     l_lin >>= fun l_lin ->
diff --git a/src/lib_shell/test/test_state.ml b/src/lib_shell/test/test_state.ml
index b7b573c43..987e03ae8 100644
--- a/src/lib_shell/test/test_state.ml
+++ b/src/lib_shell/test/test_state.ml
@@ -24,13 +24,13 @@ let genesis_time =
 
 module Proto = (val Registred_protocol.get_exn genesis_protocol)
 
-let genesis : State.Net.genesis = {
+let genesis : State.Chain.genesis = {
   time = genesis_time ;
   block = genesis_block ;
   protocol = genesis_protocol ;
 }
 
-let net_id = Net_id.of_block_hash genesis_block
+let chain_id = Chain_id.of_block_hash genesis_block
 
 let incr_fitness fitness =
   let new_fitness =
@@ -112,21 +112,21 @@ let build_valid_chain state vtbl pred names =
     names >>= fun _ ->
   Lwt.return ()
 
-let build_example_tree net =
+let build_example_tree chain =
   let vtbl = Hashtbl.create 23 in
-  Chain.genesis net >>= fun genesis ->
+  Chain.genesis chain >>= fun genesis ->
   Hashtbl.add vtbl "Genesis" genesis ;
-  let chain = [ "A1" ; "A2" ; "A3" ; "A4" ; "A5" ; "A6" ; "A7" ; "A8" ] in
-  build_valid_chain net vtbl genesis chain >>= fun () ->
+  let c = [ "A1" ; "A2" ; "A3" ; "A4" ; "A5" ; "A6" ; "A7" ; "A8" ] in
+  build_valid_chain chain vtbl genesis c >>= fun () ->
   let a3 = Hashtbl.find vtbl "A3" in
-  let chain = [ "B1" ; "B2" ; "B3" ; "B4" ; "B5" ; "B6" ; "B7" ; "B8" ] in
-  build_valid_chain net vtbl a3 chain >>= fun () ->
+  let c = [ "B1" ; "B2" ; "B3" ; "B4" ; "B5" ; "B6" ; "B7" ; "B8" ] in
+  build_valid_chain chain vtbl a3 c >>= fun () ->
   Lwt.return vtbl
 
 type state = {
   vblock: (string, State.Block.t) Hashtbl.t ;
   state: State.t ;
-  net: State.Net.t ;
+  chain: State.Chain.t ;
   init: unit -> State.t tzresult Lwt.t;
 }
 
@@ -148,9 +148,9 @@ let wrap_state_init f base_dir =
         ~context_root
         () in
     init () >>=? fun state ->
-    State.Net.create state genesis >>= fun net ->
-    build_example_tree net >>= fun vblock ->
-    f { state ; net ; vblock ; init } >>=? fun () ->
+    State.Chain.create state genesis >>= fun chain ->
+    build_example_tree chain >>= fun vblock ->
+    f { state ; chain ; vblock ; init } >>=? fun () ->
     return ()
   end
 
@@ -166,7 +166,7 @@ let test_init (_ : state) =
 let test_read_block (s: state) =
   Lwt_list.iter_s (fun (name, vblock) ->
       let hash = State.Block.hash vblock in
-      State.Block.read s.net hash >>= function
+      State.Block.read s.chain hash >>= function
       | Error _ ->
           Assert.fail_msg "Error while reading valid block %s" name
       | Ok _vblock' ->
@@ -238,7 +238,7 @@ let test_ancestor s =
 
 let test_locator s =
   let check_locator length h1 expected =
-    State.compute_locator s.net
+    State.compute_locator s.chain
       ~size:length (vblock s h1) >>= fun l ->
     let _, l = (l : Block_locator.t :> _ * _) in
     if List.length l <> List.length expected then
@@ -276,7 +276,7 @@ let compare s name heads l =
     l
 
 let test_known_heads s =
-  Chain.known_heads s.net >>= fun heads ->
+  Chain.known_heads s.chain >>= fun heads ->
   compare s "initial" heads ["A8";"B8"] ;
   return ()
 
@@ -286,11 +286,11 @@ let test_known_heads s =
 (** Chain.head/set_head *)
 
 let test_head s =
-  Chain.head s.net >>= fun head ->
+  Chain.head s.chain >>= fun head ->
   if not (Block_hash.equal (State.Block.hash head) genesis_block) then
     Assert.fail_msg "unexpected head" ;
-  Chain.set_head s.net (vblock s "A6") >>= fun _ ->
-  Chain.head s.net >>= fun head ->
+  Chain.set_head s.chain (vblock s "A6") >>= fun _ ->
+  Chain.head s.chain >>= fun head ->
   if not (Block_hash.equal (State.Block.hash head) (State.Block.hash @@ vblock s "A6")) then
     Assert.fail_msg "unexpected head" ;
   return ()
@@ -302,7 +302,7 @@ let test_head s =
 
 let test_mem s =
   let mem s x =
-    Chain.mem s.net (State.Block.hash @@ vblock s x) in
+    Chain.mem s.chain (State.Block.hash @@ vblock s x) in
   let test_mem s x =
     mem s x >>= function
     | true -> Lwt.return_unit
@@ -317,21 +317,21 @@ let test_mem s =
   test_not_mem s "B1" >>= fun () ->
   test_not_mem s "B6" >>= fun () ->
   test_not_mem s "B8" >>= fun () ->
-  Chain.set_head s.net (vblock s "A8") >>= fun _ ->
+  Chain.set_head s.chain (vblock s "A8") >>= fun _ ->
   test_mem s "A3" >>= fun () ->
   test_mem s "A6" >>= fun () ->
   test_mem s "A8" >>= fun () ->
   test_not_mem s "B1" >>= fun () ->
   test_not_mem s "B6" >>= fun () ->
   test_not_mem s "B8" >>= fun () ->
-  Chain.set_head s.net (vblock s "A6") >>= fun _ ->
+  Chain.set_head s.chain (vblock s "A6") >>= fun _ ->
   test_mem s "A3" >>= fun () ->
   test_mem s "A6" >>= fun () ->
   test_not_mem s "A8" >>= fun () ->
   test_not_mem s "B1" >>= fun () ->
   test_not_mem s "B6" >>= fun () ->
   test_not_mem s "B8" >>= fun () ->
-  Chain.set_head s.net (vblock s "B6") >>= fun _ ->
+  Chain.set_head s.chain (vblock s "B6") >>= fun _ ->
   test_mem s "A3" >>= fun () ->
   test_not_mem s "A4" >>= fun () ->
   test_not_mem s "A6" >>= fun () ->
@@ -339,7 +339,7 @@ let test_mem s =
   test_mem s "B1" >>= fun () ->
   test_mem s "B6" >>= fun () ->
   test_not_mem s "B8" >>= fun () ->
-  Chain.set_head s.net (vblock s "B8") >>= fun _ ->
+  Chain.set_head s.chain (vblock s "B8") >>= fun _ ->
   test_mem s "A3" >>= fun () ->
   test_not_mem s "A4" >>= fun () ->
   test_not_mem s "A6" >>= fun () ->
@@ -384,9 +384,9 @@ let test_new_blocks s =
 
 let test_find_new s =
   let test s h expected =
-    State.compute_locator s.net ~size:50 (vblock s h) >>= fun loc ->
+    State.compute_locator s.chain ~size:50 (vblock s h) >>= fun loc ->
     Block_locator_iterator.find_new
-      s.net loc (List.length expected) >>= fun blocks ->
+      s.chain loc (List.length expected) >>= fun blocks ->
     if List.length blocks <> List.length expected then
       Assert.fail_msg
         "Invalid find new length %s (found: %d, expected: %d)"
@@ -398,7 +398,7 @@ let test_find_new s =
       blocks expected ;
     Lwt.return_unit
   in
-  Chain.set_head s.net (vblock s "A8") >>= fun _ ->
+  Chain.set_head s.chain (vblock s "A8") >>= fun _ ->
   test s "A6" [] >>= fun () ->
   test s "A6" ["A7";"A8"] >>= fun () ->
   test s "A6" ["A7"] >>= fun () ->
@@ -433,7 +433,5 @@ let wrap (n, f) =
     end
   end
 
-let () =
-  Alcotest.run ~argv:[|""|] "tezos-shell" [
-    "state", List.map wrap tests
-  ]
+let tests =List.map wrap tests
+
diff --git a/src/lib_storage/test/test_store.ml b/src/lib_shell/test/test_store.ml
similarity index 99%
rename from src/lib_storage/test/test_store.ml
rename to src/lib_shell/test/test_store.ml
index 9ac7c0c14..25e6339a5 100644
--- a/src/lib_storage/test/test_store.ml
+++ b/src/lib_shell/test/test_store.ml
@@ -54,7 +54,7 @@ let wrap_raw_store_init f _ () =
 
 let test_init _ = Lwt.return_unit
 
-let net_id = Net_id.of_block_hash genesis_block
+let chain_id = Chain_id.of_block_hash genesis_block
 
 (** Operation store *)
 
@@ -120,7 +120,7 @@ let check_block s h b =
       exit 1
 
 let test_block s =
-  let s = Store.Net.get s net_id in
+  let s = Store.Chain.get s chain_id in
   let s = Store.Block.get s in
   Block.Contents.store (s, bh1) b1 >>= fun () ->
   Block.Contents.store (s, bh2) b2 >>= fun () ->
@@ -130,7 +130,7 @@ let test_block s =
   check_block s bh3 b3
 
 let test_expand s =
-  let s = Store.Net.get s net_id in
+  let s = Store.Chain.get s chain_id in
   let s = Store.Block.get s in
   Block.Contents.store (s, bh1) b1 >>= fun () ->
   Block.Contents.store (s, bh2) b2 >>= fun () ->
diff --git a/src/lib_shell/validator.ml b/src/lib_shell/validator.ml
index 7d2959b22..627a32c30 100644
--- a/src/lib_shell/validator.ml
+++ b/src/lib_shell/validator.ml
@@ -14,13 +14,13 @@ type t = {
   state: State.t ;
   db: Distributed_db.t ;
   block_validator: Block_validator.t ;
-  net_validator_limits: Net_validator.limits ;
+  chain_validator_limits: Chain_validator.limits ;
   peer_validator_limits: Peer_validator.limits ;
   block_validator_limits: Block_validator.limits ;
   prevalidator_limits: Prevalidator.limits ;
 
   valid_block_input: State.Block.t Lwt_watcher.input ;
-  active_nets: Net_validator.t Lwt.t Net_id.Table.t ;
+  active_chains: Chain_validator.t Lwt.t Chain_id.Table.t ;
 
 }
 
@@ -28,76 +28,76 @@ let create state db
     peer_validator_limits
     block_validator_limits
     prevalidator_limits
-    net_validator_limits =
+    chain_validator_limits =
   Block_validator.create block_validator_limits db >>= fun block_validator ->
   let valid_block_input = Lwt_watcher.create_input () in
   Lwt.return
     { state ; db ; block_validator ;
       block_validator_limits ; prevalidator_limits ;
-      peer_validator_limits ; net_validator_limits ;
+      peer_validator_limits ; chain_validator_limits ;
       valid_block_input ;
-      active_nets = Net_id.Table.create 7 }
+      active_chains = Chain_id.Table.create 7 }
 
-let activate v ?max_child_ttl net_state =
-  let net_id = State.Net.id net_state in
-  lwt_log_notice "activate network %a" Net_id.pp net_id >>= fun () ->
-  try Net_id.Table.find v.active_nets net_id
+let activate v ?max_child_ttl chain_state =
+  let chain_id = State.Chain.id chain_state in
+  lwt_log_notice "activate chain %a" Chain_id.pp chain_id >>= fun () ->
+  try Chain_id.Table.find v.active_chains chain_id
   with Not_found ->
     let nv =
-      Net_validator.create
+      Chain_validator.create
         ?max_child_ttl
         v.peer_validator_limits v.prevalidator_limits
-        v.block_validator v.valid_block_input v.db net_state
-        v.net_validator_limits in
-    Net_id.Table.add v.active_nets net_id nv ;
+        v.block_validator v.valid_block_input v.db chain_state
+        v.chain_validator_limits in
+    Chain_id.Table.add v.active_chains chain_id nv ;
     nv
 
-let get_exn { active_nets } net_id =
-  Net_id.Table.find active_nets net_id
+let get_exn { active_chains } chain_id =
+  Chain_id.Table.find active_chains chain_id
 
 type error +=
-  | Inactive_network of Net_id.t
+  | Inactive_chain of Chain_id.t
 
 let () =
   register_error_kind `Branch
-    ~id: "node.validator.inactive_network"
-    ~title: "Inactive network"
-    ~description: "Attempted validation of a block from an inactive network."
-    ~pp: (fun ppf net ->
+    ~id: "node.validator.inactive_chain"
+    ~title: "Inactive chain"
+    ~description: "Attempted validation of a block from an inactive chain."
+    ~pp: (fun ppf chain ->
         Format.fprintf ppf
-          "Tried to validate a block from network %a, \
+          "Tried to validate a block from chain %a, \
            that is not currently considered active."
-          Net_id.pp net)
-    Data_encoding.(obj1 (req "inactive_network" Net_id.encoding))
-    (function Inactive_network net -> Some net | _ -> None)
-    (fun net -> Inactive_network net)
+          Chain_id.pp chain)
+    Data_encoding.(obj1 (req "inactive_chain" Chain_id.encoding))
+    (function Inactive_chain chain -> Some chain | _ -> None)
+    (fun chain -> Inactive_chain chain)
 
-let get v net_id =
-  try get_exn v net_id >>= fun nv -> return nv
-  with Not_found -> fail (Inactive_network net_id)
+let get v chain_id =
+  try get_exn v chain_id >>= fun nv -> return nv
+  with Not_found -> fail (Inactive_chain chain_id)
 
-let validate_block v ?(force = false) ?net_id bytes operations =
+let validate_block v ?(force = false) ?chain_id bytes operations =
   let hash = Block_hash.hash_bytes [bytes] in
   match Block_header.of_bytes bytes with
   | None -> failwith "Cannot parse block header."
   | Some block ->
       begin
-        match net_id with
+        match chain_id with
         | None -> begin
             Distributed_db.read_block_header
               v.db block.shell.predecessor >>= function
             | None ->
                 failwith "Unknown predecessor (%a), cannot inject the block."
                   Block_hash.pp_short block.shell.predecessor
-            | Some (net_id, _bh) -> get v net_id
+            | Some (chain_id, _bh) -> get v chain_id
           end
-        | Some net_id ->
-            get v net_id >>=? fun nv ->
+        | Some chain_id ->
+            get v chain_id >>=? fun nv ->
             if force then
               return nv
             else
               Distributed_db.Block_header.known
-                (Net_validator.net_db nv)
+                (Chain_validator.chain_db nv)
                 block.shell.predecessor >>= function
               | true ->
                   return nv
@@ -106,36 +106,36 @@ let validate_block v ?(force = false) ?net_id bytes operations =
                     Block_hash.pp_short block.shell.predecessor
       end >>=? fun nv ->
       let validation =
-        Net_validator.validate_block nv ~force hash block operations in
+        Chain_validator.validate_block nv ~force hash block operations in
       return (hash, validation)
 
-let shutdown { active_nets ; block_validator } =
+let shutdown { active_chains ; block_validator } =
   let jobs =
     Block_validator.shutdown block_validator ::
-    Net_id.Table.fold
-      (fun _ nv acc -> (nv >>= Net_validator.shutdown) :: acc)
-      active_nets [] in
+    Chain_id.Table.fold
+      (fun _ nv acc -> (nv >>= Chain_validator.shutdown) :: acc)
+      active_chains [] in
   Lwt.join jobs >>= fun () ->
   Lwt.return_unit
 
 let watcher { valid_block_input } =
   Lwt_watcher.create_stream valid_block_input
 
-let inject_operation v ?net_id op =
+let inject_operation v ?chain_id op =
   begin
-    match net_id with
+    match chain_id with
     | None -> begin
         Distributed_db.read_block_header
           v.db op.Operation.shell.branch >>= function
         | None ->
             failwith "Unknown branch (%a), cannot inject the operation."
               Block_hash.pp_short op.shell.branch
-        | Some (net_id, _bh) -> get v net_id
+        | Some (chain_id, _bh) -> get v chain_id
       end
-    | Some net_id ->
-        get v net_id >>=? fun nv ->
+    | Some chain_id ->
+        get v chain_id >>=? fun nv ->
         Distributed_db.Block_header.known
-          (Net_validator.net_db nv)
+          (Chain_validator.chain_db nv)
           op.shell.branch >>= function
         | true ->
             return nv
@@ -143,5 +143,5 @@ let inject_operation v ?net_id op =
             failwith "Unknown branch (%a), cannot inject the operation."
               Block_hash.pp_short op.shell.branch
   end >>=? fun nv ->
-  let pv = Net_validator.prevalidator nv in
+  let pv = Chain_validator.prevalidator nv in
   Prevalidator.inject_operation pv op
diff --git a/src/lib_shell/validator.mli b/src/lib_shell/validator.mli
index 50da1416a..289575adf 100644
--- a/src/lib_shell/validator.mli
+++ b/src/lib_shell/validator.mli
@@ -17,33 +17,33 @@ val create:
   Peer_validator.limits ->
   Block_validator.limits ->
   Prevalidator.limits ->
-  Net_validator.limits ->
+  Chain_validator.limits ->
   t Lwt.t
 val shutdown: t -> unit Lwt.t
 
-(** Start the validation scheduler of a given network. *)
+(** Start the validation scheduler of a given chain. *)
 val activate:
   t ->
   ?max_child_ttl:int ->
-  State.Net.t -> Net_validator.t Lwt.t
+  State.Chain.t -> Chain_validator.t Lwt.t
 
 type error +=
-  | Inactive_network of Net_id.t
-val get: t -> Net_id.t -> Net_validator.t tzresult Lwt.t
-val get_exn: t -> Net_id.t -> Net_validator.t Lwt.t
+  | Inactive_chain of Chain_id.t
+val get: t -> Chain_id.t -> Chain_validator.t tzresult Lwt.t
+val get_exn: t -> Chain_id.t -> Chain_validator.t Lwt.t
 
 (** Force the validation of a block. *)
 val validate_block:
   t ->
   ?force:bool ->
-  ?net_id:Net_id.t ->
+  ?chain_id:Chain_id.t ->
   MBytes.t -> Operation.t list list ->
   (Block_hash.t * State.Block.t tzresult Lwt.t) tzresult Lwt.t
 
-(** Monitor all the valid block (for all activate networks). *)
+(** Monitor all the valid block (for all activate chains). *)
 val watcher: t -> State.Block.t Lwt_stream.t * Lwt_watcher.stopper
 
 val inject_operation:
   t ->
-  ?net_id:Net_id.t ->
+  ?chain_id:Chain_id.t ->
   Operation.t -> unit tzresult Lwt.t
diff --git a/src/lib_shell/worker.ml b/src/lib_shell/worker.ml
index 73fb2bf87..ef3484fd3 100644
--- a/src/lib_shell/worker.ml
+++ b/src/lib_shell/worker.ml
@@ -109,8 +109,8 @@ module Make
             "Worker %s[%a] has been shut down."
             base_name Name.pp name)
       Data_encoding.(obj1 (req "worker_id" Name.encoding))
-      (function Closed net_id -> Some net_id | _ -> None)
-      (fun net_id -> Closed net_id)
+      (function Closed chain_id -> Some chain_id | _ -> None)
+      (fun chain_id -> Closed chain_id)
 
   let queue_item ?u r =
     Time.now (),
diff --git a/src/lib_shell_services/block_services.ml b/src/lib_shell_services/block_services.ml
index 99b396780..043111719 100644
--- a/src/lib_shell_services/block_services.ml
+++ b/src/lib_shell_services/block_services.ml
@@ -47,7 +47,7 @@ let to_string = function
 
 type block_info = {
   hash: Block_hash.t ;
-  net_id: Net_id.t ;
+  chain_id: Chain_id.t ;
   level: Int32.t ;
   proto_level: int ; (* uint8 *)
   predecessor: Block_hash.t ;
@@ -59,7 +59,7 @@ type block_info = {
   data: MBytes.t ;
   operations: (Operation_hash.t * Operation.t) list list option ;
   protocol: Protocol_hash.t ;
-  test_network: Test_network_status.t ;
+  test_chain: Test_chain_status.t ;
 }
 
 let block_info_encoding =
@@ -68,35 +68,35 @@ let block_info_encoding =
       (obj1 (req "hash" Operation_hash.encoding))
       Operation.encoding in
   conv
-    (fun { hash ; net_id ; level ; proto_level ; predecessor ;
+    (fun { hash ; chain_id ; level ; proto_level ; predecessor ;
            fitness ; timestamp ; protocol ;
            validation_passes ; operations_hash ; context ; data ;
-           operations ; test_network } ->
-      ((hash, net_id, operations, protocol, test_network),
+           operations ; test_chain } ->
+      ((hash, chain_id, operations, protocol, test_chain),
        { Block_header.shell =
            { level ; proto_level ; predecessor ;
              timestamp ; validation_passes ; operations_hash ; fitness ;
              context } ;
          proto = data }))
-    (fun ((hash, net_id, operations, protocol, test_network),
+    (fun ((hash, chain_id, operations, protocol, test_chain),
           { Block_header.shell =
               { level ; proto_level ; predecessor ;
                 timestamp ; validation_passes ; operations_hash ; fitness ;
                 context } ;
             proto = data }) ->
-      { hash ; net_id ; level ; proto_level ; predecessor ;
+      { hash ; chain_id ; level ; proto_level ; predecessor ;
         fitness ; timestamp ; protocol ;
         validation_passes ; operations_hash ; context ; data ;
-        operations ; test_network })
+        operations ; test_chain })
     (dynamic_size
        (merge_objs
           (obj5
              (req "hash" Block_hash.encoding)
-             (req "net_id" Net_id.encoding)
+             (req "chain_id" Chain_id.encoding)
              (opt "operations" (dynamic_size (list (dynamic_size (list (dynamic_size operation_encoding))))))
              (req "protocol" Protocol_hash.encoding)
-             (dft "test_network"
-                Test_network_status.encoding Not_running))
+             (dft "test_chain"
+                Test_chain_status.encoding Not_running))
           Block_header.encoding))
 
 type preapply_result = {
@@ -143,13 +143,13 @@ module S = struct
       ~output: block_info_encoding
       block_path
 
-  let net_id =
+  let chain_id =
     RPC_service.post_service
-      ~description:"Returns the net of the chain in which the block belongs."
+      ~description:"Returns the chain in which the block belongs."
       ~query: RPC_query.empty
       ~input: empty
-      ~output: (obj1 (req "net_id" Net_id.encoding))
-      RPC_path.(block_path / "net_id")
+      ~output: (obj1 (req "chain_id" Chain_id.encoding))
+      RPC_path.(block_path / "chain_id")
 
   let level =
     RPC_service.post_service
@@ -245,13 +245,13 @@ module S = struct
       ~output: (obj1 (req "protocol" Protocol_hash.encoding))
       RPC_path.(block_path / "protocol")
 
-  let test_network =
+  let test_chain =
     RPC_service.post_service
-      ~description:"Returns the status of the associated test network."
+      ~description:"Returns the status of the associated test chain."
       ~query: RPC_query.empty
       ~input: empty
-      ~output: Test_network_status.encoding
-      RPC_path.(block_path / "test_network")
+      ~output: Test_chain_status.encoding
+      RPC_path.(block_path / "test_chain")
 
   let pending_operations =
     let operation_encoding =
@@ -432,7 +432,7 @@ let monitor_prevalidated_operations ?(contents = false) ctxt =
     ((), `Prevalidation) ()
     { contents ; monitor = true }
 
-let net_id ctxt b = make_call1 S.net_id ctxt b () ()
+let chain_id ctxt b = make_call1 S.chain_id ctxt b () ()
 let level ctxt b = make_call1 S.level ctxt b () ()
 let predecessor ctxt b = make_call1 S.predecessor ctxt b () ()
 let predecessors ctxt b n = make_call1 S.predecessors ctxt b () n
@@ -442,7 +442,7 @@ let fitness ctxt b = make_call1 S.fitness ctxt b () ()
 let operations ctxt ?(contents = false) h =
   make_call1 S.operations ctxt h () { contents ; monitor = false }
 let protocol ctxt b = make_call1 S.protocol ctxt b () ()
-let test_network ctxt b = make_call1 S.test_network ctxt b () ()
+let test_chain ctxt b = make_call1 S.test_chain ctxt b () ()
 let pending_operations ctxt b = make_call1 S.pending_operations ctxt b () ()
 let info ctxt ?(include_ops = true) h =
   make_call1 S.info ctxt h () include_ops
diff --git a/src/lib_shell_services/block_services.mli b/src/lib_shell_services/block_services.mli
index b8737729f..2f685d9ed 100644
--- a/src/lib_shell_services/block_services.mli
+++ b/src/lib_shell_services/block_services.mli
@@ -26,7 +26,7 @@ val to_string: block -> string
 
 type block_info = {
   hash: Block_hash.t ;
-  net_id: Net_id.t ;
+  chain_id: Chain_id.t ;
   level: Int32.t ;
   proto_level: int ; (* uint8 *)
   predecessor: Block_hash.t ;
@@ -38,7 +38,7 @@ type block_info = {
   data: MBytes.t ;
   operations: (Operation_hash.t * Operation.t) list list option ;
   protocol: Protocol_hash.t ;
-  test_network: Test_network_status.t ;
+  test_chain: Test_chain_status.t ;
 }
 
 type preapply_result = {
@@ -48,8 +48,8 @@ type preapply_result = {
 
 open RPC_context
 
-val net_id:
-  #simple -> block -> Net_id.t tzresult Lwt.t
+val chain_id:
+  #simple -> block -> Chain_id.t tzresult Lwt.t
 val level:
   #simple -> block -> Int32.t tzresult Lwt.t
 val predecessor:
@@ -67,8 +67,8 @@ val operations:
   block -> (Operation_hash.t * Operation.t option) list list tzresult Lwt.t
 val protocol:
   #simple -> block -> Protocol_hash.t tzresult Lwt.t
-val test_network:
-  #simple -> block -> Test_network_status.t tzresult Lwt.t
+val test_chain:
+  #simple -> block -> Test_chain_status.t tzresult Lwt.t
 
 val pending_operations:
   #simple -> block ->
@@ -119,10 +119,10 @@ module S : sig
     ([ `POST ], unit,
      unit * block, unit, bool,
      block_info) RPC_service.t
-  val net_id:
+  val chain_id:
     ([ `POST ], unit,
      unit * block, unit, unit,
-     Net_id.t) RPC_service.t
+     Chain_id.t) RPC_service.t
   val level:
     ([ `POST ], unit,
      unit * block, unit, unit,
@@ -165,10 +165,10 @@ module S : sig
     ([ `POST ], unit,
      unit * block, unit, unit,
      Protocol_hash.t) RPC_service.t
-  val test_network:
+  val test_chain:
     ([ `POST ], unit,
      unit * block, unit, unit,
-     Test_network_status.t) RPC_service.t
+     Test_chain_status.t) RPC_service.t
   val pending_operations:
     ([ `POST ], unit,
      unit * block, unit, unit,
diff --git a/src/lib_shell_services/block_validator_errors.ml b/src/lib_shell_services/block_validator_errors.ml
index ab748f876..158af8321 100644
--- a/src/lib_shell_services/block_validator_errors.ml
+++ b/src/lib_shell_services/block_validator_errors.ml
@@ -18,8 +18,8 @@ type block_error =
   | Outdated_operation of
       { operation: Operation_hash.t;
         originating_block: Block_hash.t }
-  | Expired_network of
-      { net_id: Net_id.t ;
+  | Expired_chain of
+      { chain_id: Chain_id.t ;
         expiration: Time.t ;
         timestamp: Time.t ;
       }
@@ -188,13 +188,13 @@ let pp_block_error ppf = function
         "The operation %a is outdated (originated in block: %a)"
         Operation_hash.pp_short operation
         Block_hash.pp_short originating_block
-  | Expired_network { net_id ; expiration ; timestamp } ->
+  | Expired_chain { chain_id ; expiration ; timestamp } ->
       Format.fprintf ppf
         "The block timestamp (%a) is later than \
-         its network expiration date: %a (net: %a)."
+         its chain expiration date: %a (chain: %a)."
         Time.pp_hum timestamp
         Time.pp_hum expiration
-        Net_id.pp_short net_id
+        Chain_id.pp_short chain_id
   | Unexpected_number_of_validation_passes n ->
       Format.fprintf ppf
         "Invalid number of validation passes (found: %d)"
diff --git a/src/lib_shell_services/block_validator_errors.mli b/src/lib_shell_services/block_validator_errors.mli
index 80ae7a594..fc70e4fe0 100644
--- a/src/lib_shell_services/block_validator_errors.mli
+++ b/src/lib_shell_services/block_validator_errors.mli
@@ -18,8 +18,8 @@ type block_error =
   | Outdated_operation of
       { operation: Operation_hash.t;
         originating_block: Block_hash.t }
-  | Expired_network of
-      { net_id: Net_id.t ;
+  | Expired_chain of
+      { chain_id: Chain_id.t ;
         expiration: Time.t ;
         timestamp: Time.t ;
       }
diff --git a/src/lib_shell_services/block_validator_worker_state.ml b/src/lib_shell_services/block_validator_worker_state.ml
index 6ed4c9085..781ff096d 100644
--- a/src/lib_shell_services/block_validator_worker_state.ml
+++ b/src/lib_shell_services/block_validator_worker_state.ml
@@ -9,24 +9,24 @@
 
 module Request = struct
   type view = {
-    net_id : Net_id.t ;
+    chain_id : Chain_id.t ;
     block : Block_hash.t ;
     peer : P2p_peer.Id.t option ;
   }
   let encoding =
     let open Data_encoding in
     conv
-      (fun { net_id ; block ; peer } -> (block, net_id, peer))
-      (fun (block, net_id, peer) -> { net_id ; block ; peer })
+      (fun { chain_id ; block ; peer } -> (block, chain_id, peer))
+      (fun (block, chain_id, peer) -> { chain_id ; block ; peer })
       (obj3
          (req "block" Block_hash.encoding)
-         (req "net_id" Net_id.encoding)
+         (req "chain_id" Chain_id.encoding)
          (opt "peer" P2p_peer.Id.encoding))
 
-  let pp ppf { net_id ; block ; peer } =
-    Format.fprintf ppf "Validation of %a (net: %a)"
+  let pp ppf { chain_id ; block ; peer } =
+    Format.fprintf ppf "Validation of %a (chain: %a)"
       Block_hash.pp block
-      Net_id.pp_short net_id ;
+      Chain_id.pp_short chain_id ;
     match peer with
     | None -> ()
     | Some peer ->
diff --git a/src/lib_shell_services/block_validator_worker_state.mli b/src/lib_shell_services/block_validator_worker_state.mli
index 703c31a87..856563b7c 100644
--- a/src/lib_shell_services/block_validator_worker_state.mli
+++ b/src/lib_shell_services/block_validator_worker_state.mli
@@ -9,7 +9,7 @@
 
 module Request : sig
   type view = {
-    net_id : Net_id.t ;
+    chain_id : Chain_id.t ;
     block : Block_hash.t ;
     peer: P2p_peer.Id.t option ;
   }
diff --git a/src/lib_shell_services/net_validator_worker_state.ml b/src/lib_shell_services/chain_validator_worker_state.ml
similarity index 92%
rename from src/lib_shell_services/net_validator_worker_state.ml
rename to src/lib_shell_services/chain_validator_worker_state.ml
index 3f40cd2a2..f7597a127 100644
--- a/src/lib_shell_services/net_validator_worker_state.ml
+++ b/src/lib_shell_services/chain_validator_worker_state.ml
@@ -25,7 +25,7 @@ module Event = struct
           request_status : Worker_types.request_status ;
           update : update ;
           fitness : Fitness.t }
-    | Could_not_switch_testnet of error list
+    | Could_not_switch_testchain of error list
 
   let level = function
     | Processed_block req ->
@@ -33,7 +33,7 @@ module Event = struct
           | Ignored_head -> Logging.Info
           | Branch_switch | Head_incrememt -> Logging.Notice
         end
-    | Could_not_switch_testnet _ -> Logging.Error
+    | Could_not_switch_testchain _ -> Logging.Error
 
   let encoding =
     let open Data_encoding in
@@ -56,9 +56,9 @@ module Event = struct
         case (Tag 1)
           RPC_error.encoding
           (function
-            | Could_not_switch_testnet err -> Some err
+            | Could_not_switch_testchain err -> Some err
             | _ -> None)
-          (fun err -> Could_not_switch_testnet err) ]
+          (fun err -> Could_not_switch_testchain err) ]
 
   let pp ppf = function
     | Processed_block req ->
@@ -81,8 +81,8 @@ module Event = struct
           Time.pp_hum req.request_status.pushed
           Time.pp_hum req.request_status.treated
           Time.pp_hum req.request_status.completed
-    | Could_not_switch_testnet err ->
-        Format.fprintf ppf "@[<v 2>Error while switch test network:@ %a@]"
+    | Could_not_switch_testchain err ->
+        Format.fprintf ppf "@[<v 2>Error while switching test chain:@ %a@]"
           Error_monad.pp_print_error err
 
 end
diff --git a/src/lib_shell_services/net_validator_worker_state.mli b/src/lib_shell_services/chain_validator_worker_state.mli
similarity index 96%
rename from src/lib_shell_services/net_validator_worker_state.mli
rename to src/lib_shell_services/chain_validator_worker_state.mli
index dcb146671..2df1cc1d2 100644
--- a/src/lib_shell_services/net_validator_worker_state.mli
+++ b/src/lib_shell_services/chain_validator_worker_state.mli
@@ -24,7 +24,7 @@ module Event : sig
           request_status : Worker_types.request_status ;
           update : update ;
           fitness : Fitness.t }
-    | Could_not_switch_testnet of error list
+    | Could_not_switch_testchain of error list
   val level : t -> Logging.level
   val encoding : t Data_encoding.encoding
   val pp : Format.formatter -> t -> unit
diff --git a/src/lib_shell_services/p2p_services.ml b/src/lib_shell_services/p2p_services.ml
index a3cba92be..ba4d27f5e 100644
--- a/src/lib_shell_services/p2p_services.ml
+++ b/src/lib_shell_services/p2p_services.ml
@@ -15,7 +15,7 @@ module S = struct
       ~query: RPC_query.empty
       ~input: Data_encoding.empty
       ~output: (Data_encoding.list P2p_version.encoding)
-      RPC_path.(root / "network" / "versions")
+      RPC_path.(root / "p2p" / "versions")
 
   let stat =
     RPC_service.post_service
@@ -23,7 +23,7 @@ module S = struct
       ~query: RPC_query.empty
       ~input: Data_encoding.empty
       ~output: P2p_stat.encoding
-      RPC_path.(root / "network" / "stat")
+      RPC_path.(root / "p2p" / "stat")
 
   let events =
     RPC_service.post_service
@@ -31,7 +31,7 @@ module S = struct
       ~query: RPC_query.empty
       ~input: Data_encoding.empty
       ~output: P2p_connection.Pool_event.encoding
-      RPC_path.(root / "network" / "log")
+      RPC_path.(root / "p2p" / "log")
 
   let connect =
     RPC_service.post_service
@@ -39,7 +39,7 @@ module S = struct
       ~query: RPC_query.empty
       ~input: Data_encoding.(obj1 (dft "timeout" float 5.))
       ~output: Data_encoding.empty
-      RPC_path.(root / "network" / "connect" /: P2p_point.Id.rpc_arg)
+      RPC_path.(root / "p2p" / "connect" /: P2p_point.Id.rpc_arg)
 
 end
 
@@ -62,7 +62,7 @@ module Connections = struct
         ~query: RPC_query.empty
         ~input: Data_encoding.empty
         ~output: (Data_encoding.list P2p_connection.Info.encoding)
-        RPC_path.(root / "network" / "connections")
+        RPC_path.(root / "p2p" / "connections")
 
     let info =
       RPC_service.post_service
@@ -70,7 +70,7 @@ module Connections = struct
         ~input: Data_encoding.empty
         ~output: P2p_connection.Info.encoding
         ~description:"Details about the current P2P connection to the given peer."
-        RPC_path.(root / "network" / "connections" /: P2p_peer.Id.rpc_arg)
+        RPC_path.(root / "p2p" / "connections" /: P2p_peer.Id.rpc_arg)
 
     let kick =
       RPC_service.post_service
@@ -78,7 +78,7 @@ module Connections = struct
         ~input: Data_encoding.(obj1 (req "wait" bool))
         ~output: Data_encoding.empty
         ~description:"Forced close of the current P2P connection to the given peer."
-        RPC_path.(root / "network" / "connections" /: P2p_peer.Id.rpc_arg / "kick")
+        RPC_path.(root / "p2p" / "connections" /: P2p_peer.Id.rpc_arg / "kick")
 
   end
 
@@ -98,7 +98,7 @@ module Points = struct
         ~input: Data_encoding.empty
         ~output: P2p_point.Info.encoding
         ~description: "Details about a given `IP:addr`."
-        RPC_path.(root / "network" / "points" /: P2p_point.Id.rpc_arg)
+        RPC_path.(root / "p2p" / "points" /: P2p_point.Id.rpc_arg)
 
     let events =
       RPC_service.post_service
@@ -107,7 +107,7 @@ module Points = struct
         ~output: (Data_encoding.list
                     P2p_point.Pool_event.encoding)
         ~description: "Monitor network events related to an `IP:addr`."
-        RPC_path.(root / "network" / "points" /: P2p_point.Id.rpc_arg / "log")
+        RPC_path.(root / "p2p" / "points" /: P2p_point.Id.rpc_arg / "log")
 
     let list =
       let filter =
@@ -144,7 +144,7 @@ module Peers = struct
         ~input: Data_encoding.empty
         ~output: P2p_peer.Info.encoding
         ~description:"Details about a given peer."
-        RPC_path.(root / "network" / "peers" /: P2p_peer.Id.rpc_arg)
+        RPC_path.(root / "p2p" / "peers" /: P2p_peer.Id.rpc_arg)
 
     let events =
       RPC_service.post_service
@@ -153,7 +153,7 @@ module Peers = struct
         ~output: (Data_encoding.list
                     P2p_peer.Pool_event.encoding)
         ~description:"Monitor network events related to a given peer."
-        RPC_path.(root / "network" / "peers" /: P2p_peer.Id.rpc_arg / "log")
+        RPC_path.(root / "p2p" / "peers" /: P2p_peer.Id.rpc_arg / "log")
 
     let list =
       let filter =
@@ -167,7 +167,7 @@ module Peers = struct
                                  P2p_peer.Id.encoding
                                  P2p_peer.Info.encoding))
         ~description:"List the peers the node ever met."
-        RPC_path.(root / "network" / "peers")
+        RPC_path.(root / "p2p" / "peers")
 
   end
 
diff --git a/src/lib_shell_services/shell_services.ml b/src/lib_shell_services/shell_services.ml
index 1d9a310fe..6153bb7b9 100644
--- a/src/lib_shell_services/shell_services.ml
+++ b/src/lib_shell_services/shell_services.ml
@@ -23,16 +23,16 @@ module S = struct
     raw: MBytes.t ;
     blocking: bool ;
     force: bool ;
-    net_id: Net_id.t option ;
+    chain_id: Chain_id.t option ;
     operations: Operation.t list list ;
   }
 
   let inject_block_param =
     conv
-      (fun { raw ; blocking ; force ; net_id ; operations } ->
-         (raw, blocking, force, net_id, operations))
-      (fun (raw, blocking, force, net_id, operations) ->
-         { raw ; blocking ; force ; net_id ; operations })
+      (fun { raw ; blocking ; force ; chain_id ; operations } ->
+         (raw, blocking, force, chain_id, operations))
+      (fun (raw, blocking, force, chain_id, operations) ->
+         { raw ; blocking ; force ; chain_id ; operations })
       (obj5
          (req "data" bytes)
          (dft "blocking"
@@ -49,7 +49,7 @@ module S = struct
                   the current head. (default: false)"
                bool)
             false)
-         (opt "net_id" Net_id.encoding)
+         (opt "chain_id" Chain_id.encoding)
          (req "operations"
             (describe
                ~description:"..."
@@ -92,7 +92,7 @@ module S = struct
                     (pre-)validated before answering. (default: true)"
                  bool)
               true)
-           (opt "net_id" Net_id.encoding))
+           (opt "chain_id" Chain_id.encoding))
       ~output:
         (describe
            ~title: "Hash of the injected operation" @@
@@ -158,14 +158,14 @@ let forge_block_header ctxt header =
   make_call S.forge_block_header ctxt () () header
 
 let inject_block ctxt
-    ?(async = false) ?(force = false) ?net_id
+    ?(async = false) ?(force = false) ?chain_id
     raw operations =
   make_call S.inject_block ctxt () ()
-    { raw ; blocking = not async ; force ; net_id ; operations }
+    { raw ; blocking = not async ; force ; chain_id ; operations }
 
-let inject_operation ctxt ?(async = false) ?net_id operation =
+let inject_operation ctxt ?(async = false) ?chain_id operation =
   make_call S.inject_operation ctxt () ()
-    (operation, not async, net_id)
+    (operation, not async, chain_id)
 
 let inject_protocol ctxt ?(async = false) ?force protocol =
   make_call S.inject_protocol ctxt () ()
diff --git a/src/lib_shell_services/shell_services.mli b/src/lib_shell_services/shell_services.mli
index 2eb7ac377..ab27f3ff5 100644
--- a/src/lib_shell_services/shell_services.mli
+++ b/src/lib_shell_services/shell_services.mli
@@ -17,7 +17,7 @@ val forge_block_header:
 
 val inject_block:
   #simple ->
-  ?async:bool -> ?force:bool -> ?net_id:Net_id.t ->
+  ?async:bool -> ?force:bool -> ?chain_id:Chain_id.t ->
   MBytes.t -> Operation.t list list ->
   Block_hash.t tzresult Lwt.t
 (** [inject_block cctxt ?async ?force raw_block] tries to inject
@@ -28,7 +28,7 @@ val inject_block:
 
 val inject_operation:
   #simple ->
-  ?async:bool -> ?net_id:Net_id.t ->
+  ?async:bool -> ?chain_id:Chain_id.t ->
   MBytes.t ->
   Operation_hash.t tzresult Lwt.t
 
@@ -56,7 +56,7 @@ module S : sig
     raw: MBytes.t ;
     blocking: bool ;
     force: bool ;
-    net_id: Net_id.t option ;
+    chain_id: Chain_id.t option ;
     operations: Operation.t list list ;
   }
 
@@ -67,7 +67,7 @@ module S : sig
 
   val inject_operation:
     ([ `POST ], unit,
-     unit, unit, (MBytes.t * bool * Net_id.t option),
+     unit, unit, (MBytes.t * bool * Chain_id.t option),
      Operation_hash.t) RPC_service.t
 
   val inject_protocol:
diff --git a/src/lib_shell_services/worker_services.ml b/src/lib_shell_services/worker_services.ml
index 8303aa77c..29fa61817 100644
--- a/src/lib_shell_services/worker_services.ml
+++ b/src/lib_shell_services/worker_services.ml
@@ -13,11 +13,11 @@ module Prevalidators = struct
 
   module S = struct
 
-    let (net_id_arg : Net_id.t RPC_arg.t) =
+    let (chain_id_arg : Chain_id.t RPC_arg.t) =
       RPC_arg.like
-        Net_id.rpc_arg
-        ~descr:"The network identifier of whom the prevalidator is responsible."
-        "net_id"
+        Chain_id.rpc_arg
+        ~descr:"The chain identifier of whom the prevalidator is responsible."
+        "chain_id"
 
     let list =
       RPC_service.post_service
@@ -27,7 +27,7 @@ module Prevalidators = struct
         ~output:
           (list
              (obj2
-                (req "net_id" Net_id.encoding)
+                (req "chain_id" Chain_id.encoding)
                 (req "status" (Worker_types.worker_status_encoding  RPC_error.encoding))))
         RPC_path.(root / "workers" / "prevalidators")
 
@@ -42,7 +42,7 @@ module Prevalidators = struct
              Prevalidator_worker_state.Request.encoding
              Prevalidator_worker_state.Event.encoding
              RPC_error.encoding)
-        RPC_path.(root / "workers" / "prevalidators" /: Net_id.rpc_arg )
+        RPC_path.(root / "workers" / "prevalidators" /: Chain_id.rpc_arg )
 
   end
 
@@ -80,11 +80,11 @@ module Peer_validators = struct
 
   module S = struct
 
-    let (net_id_arg : Net_id.t RPC_arg.t) =
+    let (chain_id_arg : Chain_id.t RPC_arg.t) =
       RPC_arg.like
-        Net_id.rpc_arg
-        ~descr:"The network identifier the peer validator is associated to."
-        "net_id"
+        Chain_id.rpc_arg
+        ~descr:"The chain identifier the peer validator is associated to."
+        "chain_id"
 
     let (peer_id_arg : P2p_peer.Id.t RPC_arg.t) =
       RPC_arg.make
@@ -106,7 +106,7 @@ module Peer_validators = struct
              (obj2
                 (req "peer_id" P2p_peer.Id.encoding)
                 (req "status" (Worker_types.worker_status_encoding RPC_error.encoding))))
-        RPC_path.(root / "workers" / "peer_validators" /: net_id_arg)
+        RPC_path.(root / "workers" / "peer_validators" /: chain_id_arg)
 
     let state =
       let open Data_encoding in
@@ -119,7 +119,7 @@ module Peer_validators = struct
              Peer_validator_worker_state.Request.encoding
              Peer_validator_worker_state.Event.encoding
              RPC_error.encoding)
-        RPC_path.(root / "workers" / "peer_validators" /: net_id_arg /: peer_id_arg)
+        RPC_path.(root / "workers" / "peer_validators" /: chain_id_arg /: peer_id_arg)
 
   end
 
@@ -129,39 +129,39 @@ module Peer_validators = struct
 
 end
 
-module Net_validators = struct
+module Chain_validators = struct
 
   module S = struct
-    let (net_id_arg : Net_id.t RPC_arg.t) =
+    let (chain_id_arg : Chain_id.t RPC_arg.t) =
       RPC_arg.like
-        Net_id.rpc_arg
-        ~descr:"The network identifier of whom the net validator is responsible."
-        "net_id"
+        Chain_id.rpc_arg
+        ~descr:"The chain identifier of whom the chain validator is responsible."
+        "chain_id"
 
     let list =
       RPC_service.post_service
-        ~description:"Lists the net validator workers and their status."
+        ~description:"Lists the chain validator workers and their status."
         ~query: RPC_query.empty
         ~input: empty
         ~output:
           (list
              (obj2
-                (req "net_id" Net_id.encoding)
+                (req "chain_id" Chain_id.encoding)
                 (req "status" (Worker_types.worker_status_encoding RPC_error.encoding))))
-        RPC_path.(root / "workers" / "net_validators")
+        RPC_path.(root / "workers" / "chain_validators")
 
     let state =
       let open Data_encoding in
       RPC_service.post_service
-        ~description:"Introspect the state of a net validator worker."
+        ~description:"Introspect the state of a chain validator worker."
         ~query: RPC_query.empty
         ~input: empty
         ~output:
           (Worker_types.full_status_encoding
-             Net_validator_worker_state.Request.encoding
-             Net_validator_worker_state.Event.encoding
+             Chain_validator_worker_state.Request.encoding
+             Chain_validator_worker_state.Event.encoding
              RPC_error.encoding)
-        RPC_path.(root / "workers" / "net_validators" /: net_id_arg )
+        RPC_path.(root / "workers" / "chain_validators" /: chain_id_arg )
 
   end
 
diff --git a/src/lib_shell_services/worker_services.mli b/src/lib_shell_services/worker_services.mli
index 7c412d63e..1f1ad705b 100644
--- a/src/lib_shell_services/worker_services.mli
+++ b/src/lib_shell_services/worker_services.mli
@@ -14,20 +14,20 @@ module Prevalidators : sig
   open Prevalidator_worker_state
 
   val list:
-    #simple -> (Net_id.t * Worker_types.worker_status) list tzresult Lwt.t
+    #simple -> (Chain_id.t * Worker_types.worker_status) list tzresult Lwt.t
   val state:
-    #simple -> Net_id.t -> (Request.view, Event.t) Worker_types.full_status tzresult Lwt.t
+    #simple -> Chain_id.t -> (Request.view, Event.t) Worker_types.full_status tzresult Lwt.t
 
   module S : sig
 
     val list :
       ([ `POST ],  unit,
        unit, unit, unit,
-       (Net_id.t * Worker_types.worker_status) list) RPC_service.t
+       (Chain_id.t * Worker_types.worker_status) list) RPC_service.t
 
     val state :
       ([ `POST ], unit,
-       unit * Net_id.t, unit, unit,
+       unit * Chain_id.t, unit, unit,
        (Request.view, Event.t) Worker_types.full_status) RPC_service.t
 
   end
@@ -57,48 +57,48 @@ module Peer_validators : sig
   open Peer_validator_worker_state
 
   val list:
-    #simple -> Net_id.t ->
+    #simple -> Chain_id.t ->
     (P2p_peer.Id.t * Worker_types.worker_status) list tzresult Lwt.t
 
   val state:
     #simple ->
-    Net_id.t -> P2p_peer.Id.t -> (Request.view, Event.t) Worker_types.full_status tzresult Lwt.t
+    Chain_id.t -> P2p_peer.Id.t -> (Request.view, Event.t) Worker_types.full_status tzresult Lwt.t
 
   module S : sig
 
     val list :
       ([ `POST ],  unit,
-       unit * Net_id.t, unit, unit,
+       unit * Chain_id.t, unit, unit,
        (P2p_peer.Id.t * Worker_types.worker_status) list) RPC_service.t
 
     val state :
       ([ `POST ], unit,
-       (unit * Net_id.t) * P2p_peer.Id.t, unit, unit,
+       (unit * Chain_id.t) * P2p_peer.Id.t, unit, unit,
        (Request.view, Event.t) Worker_types.full_status) RPC_service.t
 
   end
 
 end
 
-module Net_validators : sig
+module Chain_validators : sig
 
-  open Net_validator_worker_state
+  open Chain_validator_worker_state
 
   val list:
-    #simple -> (Net_id.t * Worker_types.worker_status) list tzresult Lwt.t
+    #simple -> (Chain_id.t * Worker_types.worker_status) list tzresult Lwt.t
   val state:
-    #simple -> Net_id.t -> (Request.view, Event.t) Worker_types.full_status tzresult Lwt.t
+    #simple -> Chain_id.t -> (Request.view, Event.t) Worker_types.full_status tzresult Lwt.t
 
   module S : sig
 
     val list :
       ([ `POST ],  unit,
        unit, unit, unit,
-       (Net_id.t * Worker_types.worker_status) list) RPC_service.t
+       (Chain_id.t * Worker_types.worker_status) list) RPC_service.t
 
     val state :
       ([ `POST ], unit,
-       unit * Net_id.t, unit, unit,
+       unit * Chain_id.t, unit, unit,
        (Request.view, Event.t) Worker_types.full_status) RPC_service.t
 
   end
diff --git a/src/lib_stdlib/logging.ml b/src/lib_stdlib/logging.ml
index 5b567b290..7cd74a938 100644
--- a/src/lib_stdlib/logging.ml
+++ b/src/lib_stdlib/logging.ml
@@ -67,7 +67,7 @@ module Make(S : sig val name: string end) : LOG = struct
 end
 
 module Core = Make(struct let name = "core" end)
-module Net = Make(struct let name = "net" end)
+module P2p = Make(struct let name = "p2p" end)
 module RPC = Make(struct let name = "rpc" end)
 module Db = Make(struct let name = "db" end)
 module Updater = Make(struct let name = "updater" end)
diff --git a/src/lib_stdlib/logging.mli b/src/lib_stdlib/logging.mli
index 5db0dc04d..0410bda70 100644
--- a/src/lib_stdlib/logging.mli
+++ b/src/lib_stdlib/logging.mli
@@ -26,7 +26,7 @@ module type LOG = sig
 end
 
 module Core : LOG
-module Net : LOG
+module P2p : LOG
 module RPC : LOG
 module Db : LOG
 module Updater : LOG
diff --git a/src/lib_storage/context.ml b/src/lib_storage/context.ml
index 6242e3a61..820ccc1a9 100644
--- a/src/lib_storage/context.ml
+++ b/src/lib_storage/context.ml
@@ -89,7 +89,7 @@ type t = context
 (*-- Version Access and Update -----------------------------------------------*)
 
 let current_protocol_key = ["protocol"]
-let current_test_network_key = ["test_network"]
+let current_test_chain_key = ["test_chain"]
 
 let exists index key =
   GitStore.Commit.of_hash index.repo key >>= function
@@ -178,21 +178,21 @@ let get_protocol v =
 let set_protocol v key =
   raw_set v current_protocol_key (Protocol_hash.to_bytes key)
 
-let get_test_network v =
-  raw_get v current_test_network_key >>= function
-  | None -> Lwt.fail (Failure "Unexpected error (Context.get_test_network)")
+let get_test_chain v =
+  raw_get v current_test_chain_key >>= function
+  | None -> Lwt.fail (Failure "Unexpected error (Context.get_test_chain)")
   | Some data ->
-      match Data_encoding.Binary.of_bytes Test_network_status.encoding data with
-      | None -> Lwt.fail (Failure "Unexpected error (Context.get_test_network)")
+      match Data_encoding.Binary.of_bytes Test_chain_status.encoding data with
+      | None -> Lwt.fail (Failure "Unexpected error (Context.get_test_chain)")
       | Some r -> Lwt.return r
 
-let set_test_network v id =
-  raw_set v current_test_network_key
-    (Data_encoding.Binary.to_bytes Test_network_status.encoding id)
-let del_test_network v  = raw_del v current_test_network_key
+let set_test_chain v id =
+  raw_set v current_test_chain_key
+    (Data_encoding.Binary.to_bytes Test_chain_status.encoding id)
+let del_test_chain v  = raw_del v current_test_chain_key
 
-let fork_test_network v ~protocol ~expiration =
-  set_test_network v (Forking { protocol ; expiration })
+let fork_test_chain v ~protocol ~expiration =
+  set_test_chain v (Forking { protocol ; expiration })
 
 (*-- Initialisation ----------------------------------------------------------*)
 
@@ -208,53 +208,53 @@ let init ?patch_context ~root =
       | Some patch_context -> patch_context
   }
 
-let get_branch net_id = Format.asprintf "%a" Net_id.pp net_id
+let get_branch chain_id = Format.asprintf "%a" Chain_id.pp chain_id
 
 
-let commit_genesis index ~net_id ~time ~protocol =
+let commit_genesis index ~chain_id ~time ~protocol =
   let tree = GitStore.Tree.empty in
   let ctxt = { index ; tree ; parents = [] } in
   index.patch_context ctxt >>= fun ctxt ->
   set_protocol ctxt protocol >>= fun ctxt ->
-  set_test_network ctxt Not_running >>= fun ctxt ->
+  set_test_chain ctxt Not_running >>= fun ctxt ->
   raw_commit ~time ~message:"Genesis" ctxt >>= fun commit ->
-  GitStore.Branch.set index.repo (get_branch net_id) commit >>= fun () ->
+  GitStore.Branch.set index.repo (get_branch chain_id) commit >>= fun () ->
   Lwt.return (GitStore.Commit.hash commit)
 
-let compute_testnet_genesis forked_block =
+let compute_testchain_genesis forked_block =
   let genesis = Block_hash.hash_bytes [Block_hash.to_bytes forked_block] in
-  let net_id = Net_id.of_block_hash genesis in
-  net_id, genesis
+  let chain_id = Chain_id.of_block_hash genesis in
+  chain_id, genesis
 
-let commit_test_network_genesis index forked_block time ctxt =
-  let net_id, genesis = compute_testnet_genesis forked_block in
-  let branch = get_branch net_id in
-  let message = Format.asprintf "Forking testnet: %s." branch in
+let commit_test_chain_genesis index forked_block time ctxt =
+  let chain_id, genesis = compute_testchain_genesis forked_block in
+  let branch = get_branch chain_id in
+  let message = Format.asprintf "Forking testchain: %s." branch in
   raw_commit ~time ~message ctxt >>= fun commit ->
   GitStore.Branch.set index.repo branch commit >>= fun () ->
-  return (net_id, genesis, GitStore.Commit.hash commit)
+  return (chain_id, genesis, GitStore.Commit.hash commit)
 
-let reset_test_network ctxt forked_block timestamp =
-  get_test_network ctxt >>= function
+let reset_test_chain ctxt forked_block timestamp =
+  get_test_chain ctxt >>= function
   | Not_running -> Lwt.return ctxt
   | Running { expiration } ->
       if Time.(expiration <= timestamp) then
-        set_test_network ctxt Not_running
+        set_test_chain ctxt Not_running
       else
         Lwt.return ctxt
   | Forking { protocol ; expiration } ->
-      let net_id, genesis = compute_testnet_genesis forked_block in
-      set_test_network ctxt
-        (Running { net_id ; genesis ;
+      let chain_id, genesis = compute_testchain_genesis forked_block in
+      set_test_chain ctxt
+        (Running { chain_id ; genesis ;
                    protocol ; expiration })
 
-let clear_test_network index net_id =
+let clear_test_chain index chain_id =
   (* TODO remove commits... ??? *)
-  let branch = get_branch net_id in
+  let branch = get_branch chain_id in
   GitStore.Branch.remove index.repo branch
 
-let set_head index net_id commit =
-  let branch = get_branch net_id in
+let set_head index chain_id commit =
+  let branch = get_branch chain_id in
   GitStore.Commit.of_hash index.repo commit >>= function
   | None -> assert false
   | Some commit ->
diff --git a/src/lib_storage/context.mli b/src/lib_storage/context.mli
index f243837f2..9a24996bb 100644
--- a/src/lib_storage/context.mli
+++ b/src/lib_storage/context.mli
@@ -24,14 +24,14 @@ val init:
 
 val commit_genesis:
   index ->
-  net_id:Net_id.t ->
+  chain_id:Chain_id.t ->
   time:Time.t ->
   protocol:Protocol_hash.t ->
   Context_hash.t Lwt.t
 
-val commit_test_network_genesis:
+val commit_test_chain_genesis:
   index -> Block_hash.t -> Time.t -> context ->
-  (Net_id.t * Block_hash.t * Context_hash.t) tzresult Lwt.t
+  (Chain_id.t * Block_hash.t * Context_hash.t) tzresult Lwt.t
 
 (** {2 Generic interface} ****************************************************)
 
@@ -60,7 +60,7 @@ val commit:
   ?message:string ->
   context ->
   Context_hash.t Lwt.t
-val set_head: index -> Net_id.t -> Context_hash.t -> unit Lwt.t
+val set_head: index -> Chain_id.t -> Context_hash.t -> unit Lwt.t
 val set_master: index -> Context_hash.t -> unit Lwt.t
 
 (** {2 Predefined Fields} ****************************************************)
@@ -68,13 +68,13 @@ val set_master: index -> Context_hash.t -> unit Lwt.t
 val get_protocol: context -> Protocol_hash.t Lwt.t
 val set_protocol: context -> Protocol_hash.t -> context Lwt.t
 
-val get_test_network: context -> Test_network_status.t Lwt.t
-val set_test_network: context -> Test_network_status.t -> context Lwt.t
+val get_test_chain: context -> Test_chain_status.t Lwt.t
+val set_test_chain: context -> Test_chain_status.t -> context Lwt.t
 
-val del_test_network: context -> context Lwt.t
+val del_test_chain: context -> context Lwt.t
 
-val reset_test_network: context -> Block_hash.t -> Time.t -> context Lwt.t
+val reset_test_chain: context -> Block_hash.t -> Time.t -> context Lwt.t
 
-val fork_test_network:
+val fork_test_chain:
   context -> protocol:Protocol_hash.t -> expiration:Time.t -> context Lwt.t
-val clear_test_network: index -> Net_id.t -> unit Lwt.t
+val clear_test_chain: index -> Chain_id.t -> unit Lwt.t
diff --git a/src/lib_storage/test/assert.ml b/src/lib_storage/test/assert.ml
index 13ba3ac2c..e98edaecb 100644
--- a/src/lib_storage/test/assert.ml
+++ b/src/lib_storage/test/assert.ml
@@ -23,12 +23,6 @@ let equal_string_option ?msg o1 o2 =
     | Some s -> s in
   equal ?msg ~prn o1 o2
 
-let is_false ?(msg="") x =
-  if x then fail "false" "true" msg
-
-let is_true ?(msg="") x =
-  if not x then fail "true" "false" msg
-
 let is_none ?(msg="") x =
   if x <> None then fail "None" "Some _" msg
 
@@ -48,32 +42,9 @@ let make_equal_list eq prn ?(msg="") x y =
         () in
   iter 0 x y
 
-let equal_string_list ?msg l1 l2 =
-  make_equal_list ?msg (=) (fun x -> x) l1 l2
-
 let equal_string_list_list ?msg l1 l2 =
   let pr_persist l =
     let res =
       String.concat ";" (List.map (fun s -> Printf.sprintf "%S" s) l) in
     Printf.sprintf "[%s]" res in
   make_equal_list ?msg (=) pr_persist l1 l2
-
-let equal_block_set ?msg set1 set2 =
-  let b1 = Block_hash.Set.elements set1
-  and b2 = Block_hash.Set.elements set2 in
-  make_equal_list ?msg
-    (fun h1 h2 -> Block_hash.equal h1 h2)
-    Block_hash.to_string
-    b1 b2
-
-let equal_block_map ?msg ~eq map1 map2 =
-  let b1 = Block_hash.Map.bindings map1
-  and b2 = Block_hash.Map.bindings map2 in
-  make_equal_list ?msg
-    (fun (h1, b1) (h2, b2) -> Block_hash.equal h1 h2 && eq b1 b2)
-    (fun (h1, _) -> Block_hash.to_string h1)
-    b1 b2
-
-let equal_block_hash_list ?msg l1 l2 =
-  let pr_block_hash = Block_hash.to_short_b58check in
-  make_equal_list ?msg Block_hash.equal pr_block_hash l1 l2
diff --git a/src/lib_storage/test/test.ml b/src/lib_storage/test/test.ml
index a67b878d7..decdc7a7a 100644
--- a/src/lib_storage/test/test.ml
+++ b/src/lib_storage/test/test.ml
@@ -9,6 +9,5 @@
 
 let () =
   Alcotest.run "tezos-storage" [
-    "store", Test_store.tests ;
     "context", Test_context.tests ;
   ]
diff --git a/src/lib_storage/test/test_context.ml b/src/lib_storage/test/test_context.ml
index d498bf711..8d62d9375 100644
--- a/src/lib_storage/test/test_context.ml
+++ b/src/lib_storage/test/test_context.ml
@@ -26,7 +26,7 @@ let genesis_protocol =
 let genesis_time =
   Time.of_seconds 0L
 
-let net_id = Net_id.of_block_hash genesis_block
+let chain_id = Chain_id.of_block_hash genesis_block
 
 (** Context creation *)
 
@@ -89,7 +89,7 @@ let wrap_context_init f _ () =
     let root = base_dir // "context" in
     Context.init ~root ?patch_context:None >>= fun idx ->
     Context.commit_genesis idx
-      ~net_id
+      ~chain_id
       ~time:genesis_time
       ~protocol:genesis_protocol >>= fun genesis ->
     create_block2 idx genesis >>= fun block2 ->
diff --git a/src/proto_alpha/lib_baking/client_baking_blocks.ml b/src/proto_alpha/lib_baking/client_baking_blocks.ml
index 8496eabbd..553a5b9ac 100644
--- a/src/proto_alpha/lib_baking/client_baking_blocks.ml
+++ b/src/proto_alpha/lib_baking/client_baking_blocks.ml
@@ -12,7 +12,7 @@ open Alpha_context
 
 type block_info = {
   hash: Block_hash.t ;
-  net_id: Net_id.t ;
+  chain_id: Chain_id.t ;
   predecessor: Block_hash.t ;
   fitness: MBytes.t list ;
   timestamp: Time.t ;
@@ -21,22 +21,22 @@ type block_info = {
 }
 
 let convert_block_info cctxt
-    ( { hash ; net_id ; predecessor ; fitness ; timestamp ; protocol }
+    ( { hash ; chain_id ; predecessor ; fitness ; timestamp ; protocol }
       : Block_services.block_info ) =
   Alpha_services.Context.level cctxt (`Hash hash) >>= function
   | Ok level ->
       Lwt.return
-        (Some { hash ; net_id ; predecessor ;
+        (Some { hash ; chain_id ; predecessor ;
                 fitness ; timestamp ; protocol ; level })
   | Error _ ->
       (* TODO log error *)
       Lwt.return_none
 
 let convert_block_info_err cctxt
-    ( { hash ; net_id ; predecessor ; fitness ; timestamp ; protocol }
+    ( { hash ; chain_id ; predecessor ; fitness ; timestamp ; protocol }
       : Block_services.block_info ) =
   Alpha_services.Context.level cctxt (`Hash hash) >>=? fun level ->
-  return { hash ; net_id ; predecessor ; fitness ; timestamp ; protocol ; level }
+  return { hash ; chain_id ; predecessor ; fitness ; timestamp ; protocol ; level }
 
 let info cctxt ?include_ops block =
   Block_services.info cctxt ?include_ops block >>=? fun block ->
diff --git a/src/proto_alpha/lib_baking/client_baking_blocks.mli b/src/proto_alpha/lib_baking/client_baking_blocks.mli
index d76b9a6a6..bc69e6399 100644
--- a/src/proto_alpha/lib_baking/client_baking_blocks.mli
+++ b/src/proto_alpha/lib_baking/client_baking_blocks.mli
@@ -12,7 +12,7 @@ open Alpha_context
 
 type block_info = {
   hash: Block_hash.t ;
-  net_id: Net_id.t ;
+  chain_id: Chain_id.t ;
   predecessor: Block_hash.t ;
   fitness: MBytes.t list ;
   timestamp: Time.t ;
diff --git a/src/proto_alpha/lib_baking/client_baking_endorsement.ml b/src/proto_alpha/lib_baking/client_baking_endorsement.ml
index bd651c4ad..0f31e7808 100644
--- a/src/proto_alpha/lib_baking/client_baking_endorsement.ml
+++ b/src/proto_alpha/lib_baking/client_baking_endorsement.ml
@@ -105,7 +105,7 @@ let inject_endorsement (cctxt : #Proto_alpha.full_context)
     () >>=? fun bytes ->
   Client_keys.append src_sk bytes >>=? fun signed_bytes ->
   Shell_services.inject_operation
-    cctxt ?async ~net_id:bi.net_id signed_bytes >>=? fun oph ->
+    cctxt ?async ~chain_id:bi.chain_id signed_bytes >>=? fun oph ->
   State.record_endorsement cctxt level bi.hash slot oph >>=? fun () ->
   return oph
 
diff --git a/src/proto_alpha/lib_baking/client_baking_forge.ml b/src/proto_alpha/lib_baking/client_baking_forge.ml
index c8f6c6b37..ab2d86793 100644
--- a/src/proto_alpha/lib_baking/client_baking_forge.ml
+++ b/src/proto_alpha/lib_baking/client_baking_forge.ml
@@ -61,14 +61,14 @@ let assert_valid_operations_hash shell_header operations =
         inconsistent header.")
 
 let inject_block cctxt
-    ?force ?net_id
+    ?force ?chain_id
     ~shell_header ~priority ~seed_nonce_hash ~src_sk operations =
   assert_valid_operations_hash shell_header operations >>=? fun () ->
   let block = `Hash shell_header.Tezos_base.Block_header.predecessor in
   forge_block_header cctxt block
     src_sk shell_header priority seed_nonce_hash >>=? fun signed_header ->
   Shell_services.inject_block cctxt
-    ?force ?net_id signed_header operations >>=? fun block_hash ->
+    ?force ?chain_id signed_header operations >>=? fun block_hash ->
   return block_hash
 
 type error +=
@@ -194,9 +194,9 @@ let forge_block cctxt block
     let operations =
       if not best_effort then operations
       else List.map (fun l -> List.map snd l.Preapply_result.applied) result in
-    Block_services.info cctxt block >>=? fun {net_id} ->
+    Block_services.info cctxt block >>=? fun {chain_id} ->
     inject_block cctxt
-      ?force ~net_id ~shell_header ~priority ~seed_nonce_hash ~src_sk
+      ?force ~chain_id ~shell_header ~priority ~seed_nonce_hash ~src_sk
       operations
   else
     let result =
@@ -527,7 +527,7 @@ let bake (cctxt : #Proto_alpha.full_context) state =
         Fitness.pp shell_header.fitness >>= fun () ->
       Client_keys.get_key cctxt delegate >>=? fun (_,_,src_sk) ->
       inject_block cctxt
-        ~force:true ~net_id:bi.net_id
+        ~force:true ~chain_id:bi.chain_id
         ~shell_header ~priority ~seed_nonce_hash ~src_sk
         [List.map snd operations.applied]
       |> trace_exn (Failure "Error while injecting block") >>=? fun block_hash ->
diff --git a/src/proto_alpha/lib_baking/client_baking_forge.mli b/src/proto_alpha/lib_baking/client_baking_forge.mli
index 98e243d64..1e8ac6744 100644
--- a/src/proto_alpha/lib_baking/client_baking_forge.mli
+++ b/src/proto_alpha/lib_baking/client_baking_forge.mli
@@ -19,7 +19,7 @@ val generate_seed_nonce: unit -> Nonce.t
 val inject_block:
   #Proto_alpha.rpc_context ->
   ?force:bool ->
-  ?net_id:Net_id.t ->
+  ?chain_id:Chain_id.t ->
   shell_header:Block_header.shell_header ->
   priority:int ->
   seed_nonce_hash:Nonce_hash.t ->
diff --git a/src/proto_alpha/lib_baking/client_baking_operations.ml b/src/proto_alpha/lib_baking/client_baking_operations.ml
index 0b6bd8a1e..f89874318 100644
--- a/src/proto_alpha/lib_baking/client_baking_operations.ml
+++ b/src/proto_alpha/lib_baking/client_baking_operations.ml
@@ -50,7 +50,7 @@ let filter_valid_endorsement cctxt ({ hash ; content } : operation) =
   | Some { contents = Sourced_operations (Dictator_operation _ ) }
   | Some { contents = Sourced_operations (Manager_operations _ ) } ->
       Lwt.return_none
-  | Some { shell = {net_id} ;
+  | Some { shell = {chain_id} ;
            contents =
              Sourced_operations (Delegate_operations { source ; operations }) } ->
       let source = Ed25519.Public_key.hash source in
@@ -72,7 +72,7 @@ let filter_valid_endorsement cctxt ({ hash ; content } : operation) =
                 slots in
             (* Ensure thath the block has been previously validated by
                the node. This might took some times... *)
-            Client_node_rpcs.validate_block cctxt net_id block >>= function
+            Client_node_rpcs.validate_block cctxt chain_id block >>= function
             | Error error ->
                 lwt_log_info
                   "@[<v 2>Found endorsement for an invalid block@,%a@["
diff --git a/src/proto_alpha/lib_baking/client_baking_revelation.ml b/src/proto_alpha/lib_baking/client_baking_revelation.ml
index e4372f924..4d1835ed7 100644
--- a/src/proto_alpha/lib_baking/client_baking_revelation.ml
+++ b/src/proto_alpha/lib_baking/client_baking_revelation.ml
@@ -20,7 +20,7 @@ let inject_seed_nonce_revelation rpc_config block ?async nonces =
   Alpha_services.Forge.Anonymous.operations rpc_config
     block ~branch:bi.hash operations >>=? fun bytes ->
   Shell_services.inject_operation
-    rpc_config ?async ~net_id:bi.net_id
+    rpc_config ?async ~chain_id:bi.chain_id
     bytes >>=? fun oph ->
   return oph
 
diff --git a/src/proto_alpha/lib_client/client_proto_context.ml b/src/proto_alpha/lib_client/client_proto_context.ml
index dc3ffbbda..c2afbf9ff 100644
--- a/src/proto_alpha/lib_client/client_proto_context.ml
+++ b/src/proto_alpha/lib_client/client_proto_context.ml
@@ -36,8 +36,8 @@ let get_branch rpc_config block branch =
     | `Hash h -> find_predecessor rpc_config h branch
     | `Genesis -> return `Genesis
   end >>=? fun block ->
-  Block_services.info rpc_config block >>=? fun { net_id ; hash } ->
-  return (net_id, hash)
+  Block_services.info rpc_config block >>=? fun { chain_id ; hash } ->
+  return (chain_id, hash)
 
 let parse_expression arg =
   Lwt.return
@@ -47,7 +47,7 @@ let parse_expression arg =
 let transfer rpc_config
     block ?branch
     ~source ~src_pk ~src_sk ~destination ?arg ~amount ~fee () =
-  get_branch rpc_config block branch >>=? fun (net_id, branch) ->
+  get_branch rpc_config block branch >>=? fun (chain_id, branch) ->
   begin match arg with
     | Some arg ->
         parse_expression arg >>=? fun { expanded = arg } ->
@@ -69,11 +69,11 @@ let transfer rpc_config
   Alpha_services.Helpers.apply_operation rpc_config block
     predecessor oph bytes (Some signature) >>=? fun contracts ->
   Shell_services.inject_operation
-    rpc_config ~net_id signed_bytes >>=? fun injected_oph ->
+    rpc_config ~chain_id signed_bytes >>=? fun injected_oph ->
   assert (Operation_hash.equal oph injected_oph) ;
   return (oph, contracts)
 
-let originate rpc_config ?net_id ~block ?signature bytes =
+let originate rpc_config ?chain_id ~block ?signature bytes =
   let signed_bytes =
     match signature with
     | None -> bytes
@@ -84,7 +84,7 @@ let originate rpc_config ?net_id ~block ?signature bytes =
     predecessor oph bytes signature >>=? function
   | [ contract ] ->
       Shell_services.inject_operation
-        rpc_config ?net_id signed_bytes >>=? fun injected_oph ->
+        rpc_config ?chain_id signed_bytes >>=? fun injected_oph ->
       assert (Operation_hash.equal oph injected_oph) ;
       return (oph, contract)
   | contracts ->
@@ -105,7 +105,7 @@ let operation_submitted_message (cctxt : #Client_context.logger) ?(contracts = [
 let originate_account ?branch
     ~source ~src_pk ~src_sk ~manager_pkh
     ?delegatable ?delegate ~balance ~fee block rpc_config () =
-  get_branch rpc_config block branch >>=? fun (net_id, branch) ->
+  get_branch rpc_config block branch >>=? fun (chain_id, branch) ->
   Alpha_services.Contract.counter
     rpc_config block source >>=? fun pcounter ->
   let counter = Int32.succ pcounter in
@@ -114,20 +114,20 @@ let originate_account ?branch
     ~counter ~balance ~spendable:true
     ?delegatable ?delegatePubKey:delegate ~fee () >>=? fun bytes ->
   Client_keys.sign src_sk bytes >>=? fun signature ->
-  originate rpc_config ~block ~net_id ~signature bytes
+  originate rpc_config ~block ~chain_id ~signature bytes
 
 let faucet ?branch ~manager_pkh block rpc_config () =
-  get_branch rpc_config block branch >>=? fun (net_id, branch) ->
+  get_branch rpc_config block branch >>=? fun (chain_id, branch) ->
   let nonce = Rand.generate Constants_repr.nonce_length in
   Alpha_services.Forge.Anonymous.faucet
     rpc_config block ~branch ~id:manager_pkh ~nonce () >>=? fun bytes ->
-  originate rpc_config ~net_id ~block bytes
+  originate rpc_config ~chain_id ~block bytes
 
 let delegate_contract rpc_config
     block ?branch
     ~source ?src_pk ~manager_sk
     ~fee delegate_opt =
-  get_branch rpc_config block branch >>=? fun (net_id, branch) ->
+  get_branch rpc_config block branch >>=? fun (chain_id, branch) ->
   Alpha_services.Contract.counter
     rpc_config block source >>=? fun pcounter ->
   let counter = Int32.succ pcounter in
@@ -138,7 +138,7 @@ let delegate_contract rpc_config
   let signed_bytes = Ed25519.Signature.concat bytes signature in
   let oph = Operation_hash.hash_bytes [ signed_bytes ] in
   Shell_services.inject_operation
-    rpc_config ~net_id signed_bytes >>=? fun injected_oph ->
+    rpc_config ~chain_id signed_bytes >>=? fun injected_oph ->
   assert (Operation_hash.equal oph injected_oph) ;
   return oph
 
@@ -180,14 +180,14 @@ let get_manager (cctxt : #Proto_alpha.full_context) block source =
 let dictate rpc_config block command seckey =
   let block = Block_services.last_baked_block block in
   Block_services.info
-    rpc_config block >>=? fun { net_id ; hash = branch } ->
+    rpc_config block >>=? fun { chain_id ; hash = branch } ->
   Alpha_services.Forge.Dictator.operation
     rpc_config block ~branch command >>=? fun bytes ->
   let signature = Ed25519.sign seckey bytes in
   let signed_bytes = Ed25519.Signature.concat bytes signature in
   let oph = Operation_hash.hash_bytes [ signed_bytes ] in
   Shell_services.inject_operation
-    rpc_config ~net_id signed_bytes >>=? fun injected_oph ->
+    rpc_config ~chain_id signed_bytes >>=? fun injected_oph ->
   assert (Operation_hash.equal oph injected_oph) ;
   return oph
 
@@ -225,7 +225,7 @@ let originate_contract
   Alpha_services.Contract.counter
     cctxt block source >>=? fun pcounter ->
   let counter = Int32.succ pcounter in
-  get_branch cctxt block None >>=? fun (_net_id, branch) ->
+  get_branch cctxt block None >>=? fun (_chain_id, branch) ->
   Alpha_services.Forge.Manager.origination cctxt block
     ~branch ~source ~sourcePubKey:src_pk ~managerPubKey:manager
     ~counter ~balance ~spendable:spendable
diff --git a/src/proto_alpha/lib_client_commands/client_proto_context_commands.ml b/src/proto_alpha/lib_client_commands/client_proto_context_commands.ml
index cb6a11a49..0dbcde608 100644
--- a/src/proto_alpha/lib_client_commands/client_proto_context_commands.ml
+++ b/src/proto_alpha/lib_client_commands/client_proto_context_commands.ml
@@ -272,7 +272,7 @@ let commands () =
        @@ stop)
       begin fun () hash seckey cctxt ->
         dictate cctxt cctxt#block
-          (Activate_testnet hash) seckey >>=? fun oph ->
+          (Activate_testchain hash) seckey >>=? fun oph ->
         operation_submitted_message cctxt oph
       end ;
 
diff --git a/src/proto_alpha/lib_protocol/src/alpha_context.ml b/src/proto_alpha/lib_protocol/src/alpha_context.ml
index 3feafd805..f785a4df8 100644
--- a/src/proto_alpha/lib_protocol/src/alpha_context.ml
+++ b/src/proto_alpha/lib_protocol/src/alpha_context.ml
@@ -148,7 +148,7 @@ let finalize ?commit_message:message c =
 let configure_sandbox = Raw_context.configure_sandbox
 
 let activate = Raw_context.activate
-let fork_test_network = Raw_context.fork_test_network
+let fork_test_chain = Raw_context.fork_test_chain
 
 let faucet_count = Raw_context.faucet_count
 let incr_faucet_count = Raw_context.incr_faucet_count
diff --git a/src/proto_alpha/lib_protocol/src/alpha_context.mli b/src/proto_alpha/lib_protocol/src/alpha_context.mli
index 6b29978e6..ec722c048 100644
--- a/src/proto_alpha/lib_protocol/src/alpha_context.mli
+++ b/src/proto_alpha/lib_protocol/src/alpha_context.mli
@@ -599,7 +599,7 @@ and delegate_operation =
 
 and dictator_operation =
   | Activate of Protocol_hash.t
-  | Activate_testnet of Protocol_hash.t
+  | Activate_testchain of Protocol_hash.t
 
 and counter = Int32.t
 
@@ -730,7 +730,7 @@ val configure_sandbox:
   Context.t -> Data_encoding.json option -> Context.t tzresult Lwt.t
 
 val activate: context -> Protocol_hash.t -> context Lwt.t
-val fork_test_network: context -> Protocol_hash.t -> Time.t -> context Lwt.t
+val fork_test_chain: context -> Protocol_hash.t -> Time.t -> context Lwt.t
 
 val endorsement_already_recorded: context -> int -> bool
 val record_endorsement: context -> int -> context
diff --git a/src/proto_alpha/lib_protocol/src/amendment.ml b/src/proto_alpha/lib_protocol/src/amendment.ml
index 735f16203..54e39df2b 100644
--- a/src/proto_alpha/lib_protocol/src/amendment.ml
+++ b/src/proto_alpha/lib_protocol/src/amendment.ml
@@ -72,7 +72,7 @@ let start_new_voting_cycle ctxt =
         let expiration = (* in two days maximum... *)
           Time.add (Timestamp.current ctxt) (Int64.mul 48L 3600L) in
         Vote.get_current_proposal ctxt >>=? fun proposal ->
-        fork_test_network ctxt proposal expiration >>= fun ctxt ->
+        fork_test_chain ctxt proposal expiration >>= fun ctxt ->
         Vote.set_current_period_kind ctxt Testing >>=? fun ctxt ->
         return ctxt
       else
diff --git a/src/proto_alpha/lib_protocol/src/apply.ml b/src/proto_alpha/lib_protocol/src/apply.ml
index 624a4b40b..e78391a05 100644
--- a/src/proto_alpha/lib_protocol/src/apply.ml
+++ b/src/proto_alpha/lib_protocol/src/apply.ml
@@ -234,12 +234,12 @@ let apply_sourced_operation
       Operation.check_signature dictator_pubkey operation >>=? fun () ->
       activate ctxt hash >>= fun ctxt ->
       return (ctxt, origination_nonce, None)
-  | Dictator_operation (Activate_testnet hash) ->
+  | Dictator_operation (Activate_testchain hash) ->
       let dictator_pubkey = Constants.dictator_pubkey ctxt in
       Operation.check_signature dictator_pubkey operation >>=? fun () ->
       let expiration = (* in two days maximum... *)
         Time.add (Timestamp.current ctxt) (Int64.mul 48L 3600L) in
-      fork_test_network ctxt hash expiration >>= fun ctxt ->
+      fork_test_chain ctxt hash expiration >>= fun ctxt ->
       return (ctxt, origination_nonce, None)
 
 let apply_anonymous_operation ctxt baker_contract origination_nonce kind =
diff --git a/src/proto_alpha/lib_protocol/src/helpers_services.ml b/src/proto_alpha/lib_protocol/src/helpers_services.ml
index 486dc948c..4a498f50c 100644
--- a/src/proto_alpha/lib_protocol/src/helpers_services.ml
+++ b/src/proto_alpha/lib_protocol/src/helpers_services.ml
@@ -377,9 +377,9 @@ module Forge = struct
         b ~branch hash =
       operation ctxt b ~branch (Activate hash)
 
-    let activate_testnet ctxt
+    let activate_testchain ctxt
         b ~branch hash =
-      operation ctxt b ~branch (Activate_testnet hash)
+      operation ctxt b ~branch (Activate_testchain hash)
 
   end
 
diff --git a/src/proto_alpha/lib_protocol/src/helpers_services.mli b/src/proto_alpha/lib_protocol/src/helpers_services.mli
index db66a32fe..abfd93d6b 100644
--- a/src/proto_alpha/lib_protocol/src/helpers_services.mli
+++ b/src/proto_alpha/lib_protocol/src/helpers_services.mli
@@ -120,7 +120,7 @@ module Forge : sig
       branch:Block_hash.t ->
       Protocol_hash.t -> MBytes.t shell_tzresult Lwt.t
 
-    val activate_testnet:
+    val activate_testchain:
       'a #RPC_context.simple -> 'a ->
       branch:Block_hash.t ->
       Protocol_hash.t -> MBytes.t shell_tzresult Lwt.t
diff --git a/src/proto_alpha/lib_protocol/src/operation_repr.ml b/src/proto_alpha/lib_protocol/src/operation_repr.ml
index 75a1ba601..ada66d9c8 100644
--- a/src/proto_alpha/lib_protocol/src/operation_repr.ml
+++ b/src/proto_alpha/lib_protocol/src/operation_repr.ml
@@ -84,7 +84,7 @@ and delegate_operation =
 
 and dictator_operation =
   | Activate of Protocol_hash.t
-  | Activate_testnet of Protocol_hash.t
+  | Activate_testchain of Protocol_hash.t
 
 and counter = Int32.t
 
@@ -237,7 +237,7 @@ module Encoding = struct
         (fun o -> ((), o))
         (fun ((), o) -> o)
         (merge_objs
-           (obj1 (req "network" (constant name)))
+           (obj1 (req "chain" (constant name)))
            args) in
     let open Data_encoding in
     union ~tag_size:`Uint8 [
@@ -247,10 +247,10 @@ module Encoding = struct
         (function (Activate hash) -> Some hash | _ -> None)
         (fun hash -> Activate hash) ;
       case (Tag 1)
-        (mk_case "activate_testnet"
+        (mk_case "activate_testchain"
            (obj1 (req "hash" Protocol_hash.encoding)))
-        (function (Activate_testnet hash) -> Some hash | _ -> None)
-        (fun hash -> Activate_testnet hash) ;
+        (function (Activate_testchain hash) -> Some hash | _ -> None)
+        (fun hash -> Activate_testchain hash) ;
     ]
 
   let dictator_kind_case tag =
diff --git a/src/proto_alpha/lib_protocol/src/operation_repr.mli b/src/proto_alpha/lib_protocol/src/operation_repr.mli
index 8c474dace..6aa7c0448 100644
--- a/src/proto_alpha/lib_protocol/src/operation_repr.mli
+++ b/src/proto_alpha/lib_protocol/src/operation_repr.mli
@@ -84,7 +84,7 @@ and delegate_operation =
 
 and dictator_operation =
   | Activate of Protocol_hash.t
-  | Activate_testnet of Protocol_hash.t
+  | Activate_testchain of Protocol_hash.t
 
 and counter = Int32.t
 
diff --git a/src/proto_alpha/lib_protocol/src/raw_context.ml b/src/proto_alpha/lib_protocol/src/raw_context.ml
index 3e3dd685c..39388bf55 100644
--- a/src/proto_alpha/lib_protocol/src/raw_context.ml
+++ b/src/proto_alpha/lib_protocol/src/raw_context.ml
@@ -249,8 +249,8 @@ let rec double_roll_value ctxt i =
 
 let activate ({ context = c } as s) h =
   Updater.activate c h >>= fun c -> Lwt.return { s with context = c }
-let fork_test_network ({ context = c } as s) protocol expiration =
-  Updater.fork_test_network c ~protocol ~expiration >>= fun c ->
+let fork_test_chain ({ context = c } as s) protocol expiration =
+  Updater.fork_test_chain c ~protocol ~expiration >>= fun c ->
   Lwt.return { s with context = c }
 
 let register_resolvers enc resolve =
diff --git a/src/proto_alpha/lib_protocol/src/raw_context.mli b/src/proto_alpha/lib_protocol/src/raw_context.mli
index 877fdc386..41dbcca18 100644
--- a/src/proto_alpha/lib_protocol/src/raw_context.mli
+++ b/src/proto_alpha/lib_protocol/src/raw_context.mli
@@ -38,7 +38,7 @@ val prepare:
   Context.t -> (context * bool) tzresult Lwt.t
 
 val activate: context -> Protocol_hash.t -> t Lwt.t
-val fork_test_network: context -> Protocol_hash.t -> Time.t -> t Lwt.t
+val fork_test_chain: context -> Protocol_hash.t -> Time.t -> t Lwt.t
 
 val register_resolvers:
   'a Base58.encoding -> (context -> string -> 'a list Lwt.t) -> unit
diff --git a/src/proto_demo/lib_client/client_proto_main.ml b/src/proto_demo/lib_client/client_proto_main.ml
index 5b90e7a24..0478d8e79 100644
--- a/src/proto_demo/lib_client/client_proto_main.ml
+++ b/src/proto_demo/lib_client/client_proto_main.ml
@@ -55,7 +55,7 @@ let bake cctxt =
                 validation_passes = 0 ;
                 operations_hash = Operation_list_list_hash.empty } ;
       proto = MBytes.create 0 } >>=? fun bytes ->
-  Client_node_rpcs.inject_block cctxt.rpc_config ~net_id:bi.net_id bytes [] >>=? fun hash ->
+  Client_node_rpcs.inject_block cctxt.rpc_config ~chain_id:bi.chain_id bytes [] >>=? fun hash ->
   cctxt.answer "Injected %a" Block_hash.pp_short hash >>= fun () ->
   return ()
 
diff --git a/src/proto_genesis/lib_client/client_proto_main.ml b/src/proto_genesis/lib_client/client_proto_main.ml
index c749eabf4..4317ca36f 100644
--- a/src/proto_genesis/lib_client/client_proto_main.ml
+++ b/src/proto_genesis/lib_client/client_proto_main.ml
@@ -79,8 +79,8 @@ let commands () =
        @@ stop)
       begin fun timestamp hash sk cctxt ->
         bake cctxt ?timestamp cctxt#block
-          (Activate_testnet { protocol = hash ;
-                              delay = Int64.mul 24L 3600L })
+          (Activate_testchain { protocol = hash ;
+                                delay = Int64.mul 24L 3600L })
           sk >>=? fun hash ->
         cctxt#answer "Injected %a" Block_hash.pp_short hash >>= fun () ->
         return ()
diff --git a/src/proto_genesis/lib_protocol/src/data.ml b/src/proto_genesis/lib_protocol/src/data.ml
index 5c8976b5b..fbe0c0a36 100644
--- a/src/proto_genesis/lib_protocol/src/data.ml
+++ b/src/proto_genesis/lib_protocol/src/data.ml
@@ -16,8 +16,8 @@ module Command = struct
         fitness: Fitness.t ;
       }
 
-    (* Activate a protocol as a testnet *)
-    | Activate_testnet of {
+    (* Activate a protocol as a testchain *)
+    | Activate_testchain of {
         protocol: Protocol_hash.t ;
         delay: Int64.t ;
       }
@@ -47,16 +47,16 @@ module Command = struct
         (fun (protocol, fitness) ->
            Activate { protocol ; fitness }) ;
       case (Tag 1)
-        (mk_case "activate_testnet"
+        (mk_case "activate_testchain"
            (obj2
               (req "hash" Protocol_hash.encoding)
               (req "validity_time" int64)))
         (function
-          | Activate_testnet { protocol ; delay } ->
+          | Activate_testchain { protocol ; delay } ->
               Some (protocol, delay)
           | _ -> None)
         (fun (protocol, delay) ->
-           Activate_testnet { protocol ; delay }) ;
+           Activate_testchain { protocol ; delay }) ;
     ]
 
   let signed_encoding =
diff --git a/src/proto_genesis/lib_protocol/src/main.ml b/src/proto_genesis/lib_protocol/src/main.ml
index 8bfa6afbb..49db6dc5b 100644
--- a/src/proto_genesis/lib_protocol/src/main.ml
+++ b/src/proto_genesis/lib_protocol/src/main.ml
@@ -47,8 +47,8 @@ type block = {
 let max_block_length =
   Data_encoding.Binary.length
     Data.Command.encoding
-    (Activate_testnet { protocol = Protocol_hash.hash_bytes [] ;
-                        delay = 0L })
+    (Activate_testchain { protocol = Protocol_hash.hash_bytes [] ;
+                          delay = 0L })
   +
   begin
     match Data_encoding.Binary.fixed_length Ed25519.Signature.encoding with
@@ -89,11 +89,11 @@ let prepare_application ctxt command timestamp fitness =
       return { Updater.message ; context = ctxt ;
                fitness ; max_operations_ttl = 0 ;
                max_operation_data_length = 0 }
-  | Activate_testnet { protocol = hash ; delay } ->
+  | Activate_testchain { protocol = hash ; delay } ->
       let message =
-        Some (Format.asprintf "activate testnet %a" Protocol_hash.pp_short hash) in
+        Some (Format.asprintf "activate testchain %a" Protocol_hash.pp_short hash) in
       let expiration = Time.add timestamp delay in
-      Updater.fork_test_network ctxt ~protocol:hash ~expiration >>= fun ctxt ->
+      Updater.fork_test_chain ctxt ~protocol:hash ~expiration >>= fun ctxt ->
       return { Updater.message ; context = ctxt ; fitness ;
                max_operations_ttl = 0 ;
                max_operation_data_length = 0 }