diff --git a/lib/dune b/lib/dune
index f5c1898..71009f1 100644
--- a/lib/dune
+++ b/lib/dune
@@ -1,4 +1,4 @@
 (library
  (name pollinate)
  (public_name pollinate)
- (libraries pollinate.common pollinate.node))
+ (libraries pollinate.common pollinate.pnode))
diff --git a/lib/node/dune b/lib/node/dune
deleted file mode 100644
index b911382..0000000
--- a/lib/node/dune
+++ /dev/null
@@ -1,6 +0,0 @@
-(library
- (name node)
- (public_name pollinate.node)
- (libraries bin_prot lwt lwt.unix pollinate.common)
- (preprocess
-  (pps ppx_bin_prot ppx_deriving.show lwt_ppx)))
diff --git a/lib/node/client.ml b/lib/pnode/client.ml
similarity index 78%
rename from lib/node/client.ml
rename to lib/pnode/client.ml
index 7bc8b9f..05a76ce 100644
--- a/lib/node/client.ml
+++ b/lib/pnode/client.ml
@@ -15,7 +15,7 @@ let peer_from { address; peers; _ } =
 let add_peer node (peer : Peer.t) =
   Base.Hashtbl.add node.peers ~key:peer.address ~data:peer
 
-let create_request node recipient payload =
+let create_request node recipient (payload, payload_signature) =
   Mutex.with_lock !node.current_request_id (fun id ->
       id := !id + 1;
       Lwt.return
@@ -28,9 +28,10 @@ let create_request node recipient payload =
             sender = !node.address;
             recipients = [recipient];
             payload;
+            payload_signature;
           })
 
-let create_response node request payload =
+let create_response node request (payload, payload_signature) =
   Message.
     {
       category = Message.Response;
@@ -40,9 +41,10 @@ let create_response node request payload =
       sender = !node.address;
       recipients = [request.sender];
       payload;
+      payload_signature;
     }
 
-let create_post node payload =
+let create_post node (payload, payload_signature) =
   Message.
     {
       category = Message.Post;
@@ -52,10 +54,11 @@ let create_post node payload =
       sender = !node.address;
       recipients = [];
       payload;
+      payload_signature;
     }
 
-let request node request recipient =
-  let%lwt message = create_request node recipient request in
+let request node (request, payload_signature) recipient =
+  let%lwt message = create_request node recipient (request, payload_signature) in
   let%lwt () = Networking.send_to node message in
   let condition_var = Lwt_condition.create () in
   Hashtbl.add !node.request_table message.id condition_var;
diff --git a/lib/node/client.mli b/lib/pnode/client.mli
similarity index 76%
rename from lib/node/client.mli
rename to lib/pnode/client.mli
index f75fe74..9292de2 100644
--- a/lib/node/client.mli
+++ b/lib/pnode/client.mli
@@ -20,16 +20,17 @@ val post : node ref -> Message.t -> unit
 
 (** [create_request node recipient payload] creates a [Message.t] of the {i Request category}
 addressed to {i recipient} containing {i payload}. *)
-val create_request : node ref -> Address.t -> bytes -> Message.t Lwt.t
+val create_request :
+  node ref -> Address.t -> bytes * bytes option -> Message.t Lwt.t
 
 (** [create_response node request payload] creates a [Message.t] of the {i Response category}
 that responds to {i request} whose content is {i payload}. *)
-val create_response : node ref -> Message.t -> bytes -> Message.t
+val create_response : node ref -> Message.t -> bytes * bytes option -> Message.t
 
 (** Sends an encoded {i request} to the specified peer and
 returns a promise holding the response from the peer. This
 function blocks the current thread of execution until a response
 arrives. *)
-val request : node ref -> bytes -> Address.t -> Message.t Lwt.t
+val request : node ref -> bytes * bytes option -> Address.t -> Message.t Lwt.t
 
-val create_post : node ref -> bytes -> Message.t
+val create_post : node ref -> bytes * bytes option -> Message.t
diff --git a/lib/node/disseminator.ml b/lib/pnode/disseminator.ml
similarity index 100%
rename from lib/node/disseminator.ml
rename to lib/pnode/disseminator.ml
diff --git a/lib/node/disseminator.mli b/lib/pnode/disseminator.mli
similarity index 100%
rename from lib/node/disseminator.mli
rename to lib/pnode/disseminator.mli
diff --git a/lib/pnode/dune b/lib/pnode/dune
new file mode 100644
index 0000000..d250c7b
--- /dev/null
+++ b/lib/pnode/dune
@@ -0,0 +1,11 @@
+(library
+ (name pnode)
+ (public_name pollinate.pnode)
+ (libraries bin_prot lwt lwt.unix pollinate.common)
+ (preprocess
+  (pps
+   ppx_bin_prot
+   lwt_ppx
+   ppx_deriving.eq
+   ppx_deriving.ord
+   ppx_deriving.show)))
diff --git a/lib/node/failure_detector.ml b/lib/pnode/failure_detector.ml
similarity index 99%
rename from lib/node/failure_detector.ml
rename to lib/pnode/failure_detector.ml
index 7866ae9..4ce1d07 100644
--- a/lib/node/failure_detector.ml
+++ b/lib/pnode/failure_detector.ml
@@ -64,6 +64,7 @@ let create_message node message recipient =
       sender = Client.address_of !node;
       recipients = [recipient.Peer.address];
       payload = Encoding.pack bin_writer_message message;
+      payload_signature = None;
     }
 
 let send_message message node recipient =
diff --git a/lib/node/failure_detector.mli b/lib/pnode/failure_detector.mli
similarity index 100%
rename from lib/node/failure_detector.mli
rename to lib/pnode/failure_detector.mli
diff --git a/lib/node/message.ml b/lib/pnode/message.ml
similarity index 85%
rename from lib/node/message.ml
rename to lib/pnode/message.ml
index 4be371d..82cd0bb 100644
--- a/lib/node/message.ml
+++ b/lib/pnode/message.ml
@@ -8,7 +8,7 @@ type category =
   | Post
   | Failure_detection
   | Custom            of string
-[@@deriving bin_io, show]
+[@@deriving bin_io, show, eq, ord]
 
 type t = {
   category : category;
@@ -18,8 +18,9 @@ type t = {
   sender : Address.t;
   recipients : Address.t list;
   payload : bytes;
+  payload_signature : bytes option;
 }
-[@@deriving bin_io]
+[@@deriving bin_io, eq, ord]
 
 let hash_of m =
   [
diff --git a/lib/node/message.mli b/lib/pnode/message.mli
similarity index 88%
rename from lib/node/message.mli
rename to lib/pnode/message.mli
index dfca608..bc88c7e 100644
--- a/lib/node/message.mli
+++ b/lib/pnode/message.mli
@@ -17,7 +17,7 @@ type category =
   | Post
   | Failure_detection
   | Custom            of string
-[@@deriving bin_io, show]
+[@@deriving bin_io, show, eq, ord]
 
 (** Messages received from [peers] which are
 processed by the node's message handler. *)
@@ -29,7 +29,8 @@ type t = {
   sender : Address.t;
   recipients : Address.t list;
   payload : bytes;
+  payload_signature : bytes option;
 }
-[@@deriving bin_io]
+[@@deriving bin_io, eq, ord]
 
 val hash_of : t -> Digest.t
diff --git a/lib/node/networking.ml b/lib/pnode/networking.ml
similarity index 100%
rename from lib/node/networking.ml
rename to lib/pnode/networking.ml
diff --git a/lib/node/networking.mli b/lib/pnode/networking.mli
similarity index 100%
rename from lib/node/networking.mli
rename to lib/pnode/networking.mli
diff --git a/lib/node/node.ml b/lib/pnode/pnode.ml
similarity index 100%
rename from lib/node/node.ml
rename to lib/pnode/pnode.ml
diff --git a/lib/node/node.mli b/lib/pnode/pnode.mli
similarity index 93%
rename from lib/node/node.mli
rename to lib/pnode/pnode.mli
index 2b07f37..a035e0c 100644
--- a/lib/node/node.mli
+++ b/lib/pnode/pnode.mli
@@ -15,7 +15,7 @@ val init : ?init_peers:Address.t list -> Address.t -> t ref Lwt.t
 
 val run_server :
   ?preprocessor:(Message.t -> Message.t) ->
-  msg_handler:(Message.t -> bytes option) ->
+  msg_handler:(Message.t -> bytes option * bytes option) ->
   t ref ->
   'b Lwt.t
 
diff --git a/lib/node/server.ml b/lib/pnode/server.ml
similarity index 95%
rename from lib/node/server.ml
rename to lib/pnode/server.ml
index e74eedb..e8463b2 100644
--- a/lib/node/server.ml
+++ b/lib/pnode/server.ml
@@ -26,7 +26,8 @@ let handle_response node res =
 
    Otherwise, we just apply the message handler and that's it.
 *)
-let process_message node preprocessor msg_handler =
+let process_message node preprocessor
+    (msg_handler : Message.t -> bytes option * bytes option) =
   let open Message in
   let%lwt message = Networking.recv_next node in
   let message = preprocessor message in
@@ -44,11 +45,11 @@ let process_message node preprocessor msg_handler =
              !node.address.address !node.address.port message.sender.address
              message.sender.port) in
       match msg_handler message with
-      | Some response ->
-        response
+      | Some payload, signature_payload ->
+        (payload, signature_payload)
         |> Client.create_response node message
         |> Networking.send_to node
-      | None -> Lwt.return ())
+      | None, _ -> Lwt.return ())
     | Failure_detection -> Failure_detector.handle_message node message
     | Post ->
       if not (Disseminator.seen !node.disseminator message) then (
diff --git a/lib/node/server.mli b/lib/pnode/server.mli
similarity index 88%
rename from lib/node/server.mli
rename to lib/pnode/server.mli
index 2cfa48c..17019e0 100644
--- a/lib/node/server.mli
+++ b/lib/pnode/server.mli
@@ -4,5 +4,5 @@
 val run :
   Types.node ref ->
   (Message.t -> Message.t) ->
-  (Message.t -> bytes option) ->
+  (Message.t -> bytes option * bytes option) ->
   'b Lwt.t
diff --git a/lib/node/types.ml b/lib/pnode/types.ml
similarity index 100%
rename from lib/node/types.ml
rename to lib/pnode/types.ml
diff --git a/lib/node/types.mli b/lib/pnode/types.mli
similarity index 100%
rename from lib/node/types.mli
rename to lib/pnode/types.mli
diff --git a/lib/node/util.ml b/lib/pnode/util.ml
similarity index 100%
rename from lib/node/util.ml
rename to lib/pnode/util.ml
diff --git a/lib/pollinate.ml b/lib/pollinate.ml
index 84d1900..ab4d85a 100644
--- a/lib/pollinate.ml
+++ b/lib/pollinate.ml
@@ -1,4 +1,4 @@
 module Address = Common.Address
 module Util = Common.Util
 module Peer = Common.Peer
-module Node = Node
+module PNode = Pnode
diff --git a/test/commons.ml b/test/commons.ml
index 3b083e5..0a67326 100644
--- a/test/commons.ml
+++ b/test/commons.ml
@@ -1,6 +1,6 @@
 (** Utils function shared by the different tests modules *)
 module Commons = struct
-  open Pollinate.Node
+  open Pollinate.PNode
   open Pollinate.Util
   open Messages
 
@@ -19,15 +19,12 @@ module Commons = struct
 
   let msg_handler message =
     let open Messages in
-    let open Message in
-    match message.category with
-    | Request ->
-      let request = Encoding.unpack bin_read_request message.payload in
-      let response =
-        match request with
-        | Ping -> Pong
-        | Get -> Pong
-        | Insert _ -> Success "Successfully added value to state" in
-      Response response |> Encoding.pack bin_writer_message |> Option.some
-    | _ -> None
+    let open Pollinate.PNode.Message in
+    let request = Encoding.unpack bin_read_request message.payload in
+    let response =
+      match request with
+      | Ping -> Pong
+      | Get -> Success "Ok"
+      | Insert _ -> Success "Successfully added value to state" in
+    (Some (Encoding.pack bin_writer_message (Response response)), None)
 end
diff --git a/test/disseminator_tests.ml b/test/disseminator_tests.ml
index b865de7..27712d0 100644
--- a/test/disseminator_tests.ml
+++ b/test/disseminator_tests.ml
@@ -1,53 +1,53 @@
 open Lwt.Infix
 open Commons
 open Pollinate
-open Pollinate.Node
+open Pollinate.PNode
 
 module Disseminator_tests = struct
   let node =
     Lwt_main.run
       (let%lwt node_a =
-         Node.init ~init_peers:[] Address.{ address = "127.0.0.1"; port = 5000 }
-       in
+         PNode.init ~init_peers:[]
+           Address.{ address = "127.0.0.1"; port = 5000 } in
        Lwt.return node_a)
 
   let queue_insertion_test () =
-    let _server = Node.run_server ~msg_handler:Commons.msg_handler node in
-    Client.address_of !node
-    |> (fun Address.{ port; _ } -> port)
-    |> string_of_int
-    |> String.to_bytes
-    |> Client.create_post node
-    |> Client.post node;
+    let _server = PNode.run_server ~msg_handler:Commons.msg_handler node in
+    let payload =
+      Client.address_of !node
+      |> (fun Address.{ port; _ } -> port)
+      |> string_of_int
+      |> String.to_bytes in
+    Client.create_post node (payload, None) |> Client.post node;
 
-    Lwt.return (List.length (Node.Testing.broadcast_queue node))
+    Lwt.return (List.length (PNode.Testing.broadcast_queue node))
 
   let queue_removal_test () =
-    let _server = Node.run_server ~msg_handler:Commons.msg_handler node in
-    Client.address_of !node
-    |> (fun Address.{ port; _ } -> port)
-    |> string_of_int
-    |> String.to_bytes
-    |> Client.create_post node
-    |> Client.post node;
+    let _server = PNode.run_server ~msg_handler:Commons.msg_handler node in
+    let payload =
+      Client.address_of !node
+      |> (fun Address.{ port; _ } -> port)
+      |> string_of_int
+      |> String.to_bytes in
+    Client.create_post node (payload, None) |> Client.post node;
 
     let%lwt () =
-      while%lwt Node.Testing.disseminator_round node <= 10 do
+      while%lwt PNode.Testing.disseminator_round node <= 10 do
         Lwt_unix.sleep 0.1
       done in
-    Lwt.return (List.length (Node.Testing.broadcast_queue node))
+    Lwt.return (List.length (PNode.Testing.broadcast_queue node))
 
   let seen_message_test () =
-    let _server = Node.run_server ~msg_handler:Commons.msg_handler node in
-    let message =
+    let _server = PNode.run_server ~msg_handler:Commons.msg_handler node in
+    let payload =
       Client.address_of !node
       |> (fun Address.{ port; _ } -> port)
       |> string_of_int
-      |> String.to_bytes
-      |> Client.create_post node in
+      |> String.to_bytes in
+    let message = Client.create_post node (payload, None) in
     message |> Client.post node;
 
-    Lwt.return (Node.seen node message)
+    Lwt.return (PNode.seen node message)
 end
 
 (** Test for dissemination given a specific node. *)
diff --git a/test/failure_detector_prop.ml b/test/failure_detector_prop.ml
index 38f3c42..f7fc885 100644
--- a/test/failure_detector_prop.ml
+++ b/test/failure_detector_prop.ml
@@ -1,17 +1,17 @@
 open QCheck2.Gen
 open Pollinate.Peer
 open Pollinate
-module SUT = Pollinate.Node.Testing.Failure_detector
+module SUT = Pollinate.PNode.Testing.Failure_detector
 
 let node_a =
-  Lwt_main.run (Node.init Address.{ address = "127.0.0.1"; port = 3002 })
+  Lwt_main.run (PNode.init Address.{ address = "127.0.0.1"; port = 3002 })
 
 let update_peer =
   QCheck2.Test.make ~count:1000
     ~name:"update_neighbor_status successfully update neighbor status"
     (pair Generators.peer_gen Generators.peer_status_gen)
     (fun (neighbor, neighbor_status) ->
-      let _ = add_neighbor (Pollinate.Node.Client.peer_from !node_a) neighbor in
+      let _ = add_neighbor (Pollinate.PNode.Client.peer_from !node_a) neighbor in
       let _ = SUT.update_peer_status node_a neighbor neighbor_status in
       neighbor.status = neighbor_status)
 
diff --git a/test/failure_detector_tests.ml b/test/failure_detector_tests.ml
index 9747cf7..54abe74 100644
--- a/test/failure_detector_tests.ml
+++ b/test/failure_detector_tests.ml
@@ -1,13 +1,13 @@
 open Pollinate
-open Pollinate.Node
+open Pollinate.PNode
 open Lwt.Infix
-module SUT = Pollinate.Node.Testing.Failure_detector
+module SUT = Pollinate.PNode.Testing.Failure_detector
 
 let node_a =
-  Lwt_main.run (Node.init Address.{ address = "127.0.0.1"; port = 3003 })
+  Lwt_main.run (PNode.init Address.{ address = "127.0.0.1"; port = 3003 })
 
 let node_b =
-  Lwt_main.run (Node.init Address.{ address = "127.0.0.1"; port = 3004 })
+  Lwt_main.run (PNode.init Address.{ address = "127.0.0.1"; port = 3004 })
 
 let peer_b = Client.peer_from !node_b
 
@@ -15,7 +15,7 @@ let failure_detection () =
   let open Common.Peer in
   let open Client in
   let _ = add_peer !node_a peer_b in
-  let _ = Pollinate.Node.Client.peer_from !node_a in
+  let _ = Pollinate.PNode.Client.peer_from !node_a in
   let _ = SUT.update_peer_status node_a peer_b Suspicious in
   (* Need to wait for the timeout to be reached An other way to do, would be to change the `last_suspicious_status` of the peer *)
   let%lwt _ = Lwt_unix.sleep 9.1 in
@@ -24,7 +24,7 @@ let failure_detection () =
 
 let failure_detection_nothing_on_alive () =
   let open Common.Peer in
-  let _ = add_neighbor (Pollinate.Node.Client.peer_from !node_a) peer_b in
+  let _ = add_neighbor (Pollinate.PNode.Client.peer_from !node_a) peer_b in
   let _ = SUT.update_peer_status node_a peer_b Alive in
   let%lwt _ = SUT.failure_detection node_a in
   Lwt.return (Base.Hashtbl.length !node_a.peers = 1)
diff --git a/test/gossip_tests.ml b/test/gossip_tests.ml
index 166a2d9..56c77bd 100644
--- a/test/gossip_tests.ml
+++ b/test/gossip_tests.ml
@@ -1,7 +1,7 @@
 open Lwt.Infix
 open Commons
 open Pollinate
-open Pollinate.Node
+open Pollinate.PNode
 
 module Gossip_tests = struct
   let local_address port = Address.{ address = "127.0.0.1"; port }
@@ -41,16 +41,19 @@ module Gossip_tests = struct
             local_address 4009 ) in
 
         let%lwt node_a =
-          Node.init ~init_peers:[addr_b; addr_c; addr_e; addr_h] addr_a in
-        let%lwt node_b = Node.init ~init_peers:[addr_a; addr_d; addr_e] addr_b in
-        let%lwt node_c = Node.init ~init_peers:[addr_a; addr_f; addr_g] addr_c in
-        let%lwt node_d = Node.init ~init_peers:[addr_b] addr_d in
-        let%lwt node_e = Node.init ~init_peers:[addr_a; addr_b] addr_e in
-        let%lwt node_f = Node.init ~init_peers:[addr_c] addr_f in
-        let%lwt node_g = Node.init ~init_peers:[addr_c] addr_g in
-        let%lwt node_h = Node.init ~init_peers:[addr_a; addr_i; addr_j] addr_h in
-        let%lwt node_i = Node.init ~init_peers:[addr_h] addr_i in
-        let%lwt node_j = Node.init ~init_peers:[addr_h] addr_j in
+          PNode.init ~init_peers:[addr_b; addr_c; addr_e; addr_h] addr_a in
+        let%lwt node_b =
+          PNode.init ~init_peers:[addr_a; addr_d; addr_e] addr_b in
+        let%lwt node_c =
+          PNode.init ~init_peers:[addr_a; addr_f; addr_g] addr_c in
+        let%lwt node_d = PNode.init ~init_peers:[addr_b] addr_d in
+        let%lwt node_e = PNode.init ~init_peers:[addr_a; addr_b] addr_e in
+        let%lwt node_f = PNode.init ~init_peers:[addr_c] addr_f in
+        let%lwt node_g = PNode.init ~init_peers:[addr_c] addr_g in
+        let%lwt node_h =
+          PNode.init ~init_peers:[addr_a; addr_i; addr_j] addr_h in
+        let%lwt node_i = PNode.init ~init_peers:[addr_h] addr_i in
+        let%lwt node_j = PNode.init ~init_peers:[addr_h] addr_j in
         Lwt.return
           ( node_a,
             node_b,
@@ -96,19 +99,19 @@ module Gossip_tests = struct
   let disseminate_from _n node =
     let _ =
       List.map
-        (Node.run_server ~preprocessor:Commons.preprocessor
+        (PNode.run_server ~preprocessor:Commons.preprocessor
            ~msg_handler:Commons.msg_handler)
         nodes in
-    let message =
+    let payload =
       Client.address_of !node
       |> (fun Address.{ port; _ } -> port)
       |> string_of_int
-      |> String.to_bytes
-      |> Client.create_post node in
+      |> String.to_bytes in
+    let message = Client.create_post node (payload, None) in
     Client.post node message;
 
     let seen () =
-      nodes |> List.filter (fun n -> Node.seen n message) |> node_ports in
+      nodes |> List.filter (fun n -> PNode.seen n message) |> node_ports in
 
     let%lwt () =
       let%lwt oc =
diff --git a/test/networking_prop.ml b/test/networking_prop.ml
index 863a9ef..b5e1115 100644
--- a/test/networking_prop.ml
+++ b/test/networking_prop.ml
@@ -2,10 +2,10 @@ open QCheck2.Gen
 open Pollinate.Peer
 open Pollinate
 
-module SUT = Pollinate.Node.Testing.Networking
+module SUT = Pollinate.PNode.Testing.Networking
 
 let node_a =
-  Lwt_main.run (Node.init Address.{ address = "127.0.0.1"; port = 2002 })
+  Lwt_main.run (PNode.init Address.{ address = "127.0.0.1"; port = 2002 })
 
 let knuth_shuffle_size =
   QCheck2.Test.make ~count:1000
diff --git a/test/node_tests.ml b/test/node_tests.ml
index 84a17c7..fc56359 100644
--- a/test/node_tests.ml
+++ b/test/node_tests.ml
@@ -1,19 +1,19 @@
 open Lwt.Infix
 open Commons
 open Pollinate
-open Pollinate.Node
+open Pollinate.PNode
 open Pollinate.Util
 open Messages
 
 module Node_tests = struct
   (* Initializes two nodes and the related two peers *)
   let node_a =
-    Lwt_main.run (Node.init Address.{ address = "127.0.0.1"; port = 3000 })
+    Lwt_main.run (PNode.init Address.{ address = "127.0.0.1"; port = 3000 })
 
   let peer_a = Client.peer_from !node_a
 
   let node_b =
-    Lwt_main.run (Node.init Address.{ address = "127.0.0.1"; port = 3001 })
+    Lwt_main.run (PNode.init Address.{ address = "127.0.0.1"; port = 3001 })
 
   let peer_b = Client.peer_from !node_b
 
@@ -23,45 +23,41 @@ module Node_tests = struct
     let open Messages in
     let _ =
       Lwt_list.map_p
-        (Node.run_server ~preprocessor:Commons.preprocessor
+        (PNode.run_server ~preprocessor:Commons.preprocessor
            ~msg_handler:Commons.msg_handler)
         [node_a; node_b] in
     let get = Encoding.pack bin_writer_message (Request Get) in
 
     let%lwt { payload = res_from_b; _ } =
-      Client.request node_a get peer_b.address in
+      Client.request node_a (get, None) peer_b.address in
     let res_from_b = Encoding.unpack bin_read_response res_from_b in
-
     let%lwt { payload = res_from_a; _ } =
-      Client.request node_b get peer_a.address in
+      Client.request node_b (get, None) peer_a.address in
     let res_from_a = Encoding.unpack bin_read_response res_from_a in
-
     let res_from_b, res_from_a =
       match (res_from_b, res_from_a) with
-      | Pong, Pong -> ("Ok", "Ok")
+      | Success "Ok", Success "Ok" -> ("Ok", "Ok")
       | _ -> failwith "Incorrect response" in
-
     Lwt.return (res_from_b, res_from_a)
 
   let ping_pong () =
     let open Messages in
     let _ =
       Lwt_list.map_p
-        (Node.run_server ~preprocessor:Commons.preprocessor
+        (PNode.run_server ~preprocessor:Commons.preprocessor
            ~msg_handler:Commons.msg_handler)
         [node_a; node_b] in
     let ping = Encoding.pack bin_writer_message (Request Ping) in
 
-    let%lwt { payload = pong; _ } = Client.request node_a ping peer_b.address in
+    let%lwt { payload = pong; _ } =
+      Client.request node_a (ping, None) peer_b.address in
     let pong = Encoding.unpack bin_read_response pong in
-
     let pong =
       match pong with
       | Pong -> show_response Pong
       | _ ->
         failwith (Printf.sprintf "Incorrect response: %s" (show_response pong))
     in
-
     Lwt.return pong
 end