diff --git a/lib/wamp/message_handler.rb b/lib/wamp/message_handler.rb
index 0ad553e..cdfc9f6 100644
--- a/lib/wamp/message_handler.rb
+++ b/lib/wamp/message_handler.rb
@@ -2,6 +2,11 @@
 
 require_relative "message_handler/base"
 
+require_relative "message_handler/hello"
+require_relative "message_handler/welcome"
+require_relative "message_handler/challenge"
+require_relative "message_handler/goodbye"
+
 require_relative "message_handler/subscribe"
 require_relative "message_handler/subscribed"
 require_relative "message_handler/unsubscribe"
@@ -32,9 +37,9 @@ module MessageHandler
     # instantiate correct handler
     module ClassMethods
       def resolve(data, connection)
-        return handle_when_not_joined(data, connection) unless connection.joiner.joined?
+        # return handle_when_not_joined(data, connection) unless connection.joiner.joined?
 
-        message = connection.session.receive(data)
+        message = connection.joiner.serializer.deserialize(data)
         klass_name = demodulize(message.class.name)
         klass = constantize("Wamp::MessageHandler::#{klass_name}")
         klass.new(message, connection)
diff --git a/lib/wamp/message_handler/api.rb b/lib/wamp/message_handler/api.rb
index c9eea64..cda0018 100644
--- a/lib/wamp/message_handler/api.rb
+++ b/lib/wamp/message_handler/api.rb
@@ -8,17 +8,11 @@ module MessageHandler
     class Api
       extend Forwardable
 
-      attr_reader :connection, :session_id
+      attr_reader :connection, :session_id, :id_gen
 
       def initialize(connection)
         @connection = connection
-      end
-
-      def send_protocol_violation(text, *args, **kwargs)
-        message = Message::Abort.new({ message: text }, "wamp.error.protocol_violation", *args, **kwargs)
-        manager = Manager::Event::Abort.new(message, self)
-        connection.transmit(message.payload)
-        manager.emit_event(message)
+        @id_gen = Wampproto::IdGenerator.new
       end
 
       def subscribe(topic, handler, options = {}, &block)
@@ -63,25 +57,10 @@ def unregister(registration_id, &block)
         action.send_message(&block)
       end
 
-      def on_message(message)
-        manager = Manager::Event.resolve(message, self)
-        manager.emit_event(message)
-      end
-
-      def create_request_id
-        next_request_id
-      end
-
       private
 
       def next_request_id
-        @next_request_id = create_request_id_generator unless defined?(@next_request_id)
-        @next_request_id.call
-      end
-
-      def create_request_id_generator
-        request_id = 0
-        -> { request_id += 1 }
+        id_gen.next
       end
     end
   end
diff --git a/lib/wamp/message_handler/base.rb b/lib/wamp/message_handler/base.rb
index d4d785a..f900a00 100644
--- a/lib/wamp/message_handler/base.rb
+++ b/lib/wamp/message_handler/base.rb
@@ -14,6 +14,16 @@ def initialize(message, connection)
         @connection = connection
       end
 
+      def handle
+        raise NotImplementedError
+      end
+
+      def send_message
+        raise NotImplementedError
+      end
+
+      private
+
       def stored_data
         @stored_data ||= store.delete(store_key) || {}
       end
@@ -30,14 +40,6 @@ def identity
         message.request_id
       end
 
-      def handle
-        raise NotImplementedError
-      end
-
-      def send_message
-        raise NotImplementedError
-      end
-
       def deliver_response
         callback = stored_data.fetch(:callback, proc {})
         return unless callback
@@ -45,6 +47,10 @@ def deliver_response
         callback.call(message)
       end
 
+      def validate_received_message
+        connection.session.receive_message(message)
+      end
+
       def send_serialized(message)
         connection.transmit session.send_message(message)
       end
diff --git a/lib/wamp/message_handler/call.rb b/lib/wamp/message_handler/call.rb
index c5dc5a3..7c99beb 100644
--- a/lib/wamp/message_handler/call.rb
+++ b/lib/wamp/message_handler/call.rb
@@ -4,18 +4,10 @@ module Wamp
   module MessageHandler
     # Call
     class Call < Base
-      # Call and Result share the same request_id
-      # Invocation and Yield share the same request_id
-      def handle
-        invocation = find_connection.handle_call(message)
-        connection.invocation_requests[invocation.request_id] = message.request_id
-        connection.transmit invocation
-      end
-
       def send_message(handler)
-        send_serialized message
+        store[store_key] = { handler: handler, callback: handler }
 
-        store[store_key] = { handler: handler }
+        send_serialized message
       end
     end
   end
diff --git a/lib/wamp/message_handler/challenge.rb b/lib/wamp/message_handler/challenge.rb
new file mode 100644
index 0000000..74bfb4f
--- /dev/null
+++ b/lib/wamp/message_handler/challenge.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+module Wamp
+  module MessageHandler
+    # Challenge
+    class Challenge < Hello
+      def handle
+        connection.transmit connection.joiner.receive(connection.joiner.serializer.serialize(message))
+      end
+    end
+  end
+end
diff --git a/lib/wamp/message_handler/error.rb b/lib/wamp/message_handler/error.rb
index 8f0c268..ebfd884 100644
--- a/lib/wamp/message_handler/error.rb
+++ b/lib/wamp/message_handler/error.rb
@@ -5,7 +5,9 @@ module MessageHandler
     # Call handler with error message
     class Error < Base
       def handle
-        stored_data[:handler].call(message)
+        validate_received_message
+
+        stored_data[:callback].call(message)
       end
     end
   end
diff --git a/lib/wamp/message_handler/event.rb b/lib/wamp/message_handler/event.rb
index 1562f66..d9f51c1 100644
--- a/lib/wamp/message_handler/event.rb
+++ b/lib/wamp/message_handler/event.rb
@@ -5,6 +5,8 @@ module MessageHandler
     # publish event to subscriber
     class Event < Base
       def handle
+        validate_received_message
+
         store[alt_store_key].fetch(:handler).call(message)
       end
 
diff --git a/lib/wamp/message_handler/goodbye.rb b/lib/wamp/message_handler/goodbye.rb
new file mode 100644
index 0000000..8d5729b
--- /dev/null
+++ b/lib/wamp/message_handler/goodbye.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+module Wamp
+  module MessageHandler
+    # send unregister message
+    class Goodbye < Base
+      def send_message(&callback)
+        store[store_key] = { callback: callback }
+
+        send_serialized message
+      end
+
+      def handle
+        goodbye = Wampproto::Message::Goodbye.new({}, "wamp.close.goodbye_and_out")
+        send_serialized goodbye
+      end
+    end
+  end
+end
diff --git a/lib/wamp/message_handler/hello.rb b/lib/wamp/message_handler/hello.rb
index 02a4797..24c3c65 100644
--- a/lib/wamp/message_handler/hello.rb
+++ b/lib/wamp/message_handler/hello.rb
@@ -3,13 +3,16 @@
 module Wamp
   module MessageHandler
     # Hello
-    class Hello
-      def initialize
-        @message = message
-        @connection = connection
+    class Hello < Base
+      def handle
+        msg, is_welcome = connection.acceptor.receive(connection.serializer.serialize(message))
+        connection.transmit msg
+        connection.router.attach_client(connection) if is_welcome
       end
 
-      def send_message; end
+      def send_message
+        connection.transmit connection.joiner.send_hello
+      end
     end
   end
 end
diff --git a/lib/wamp/message_handler/invocation.rb b/lib/wamp/message_handler/invocation.rb
index 0e1a2e4..23a4f08 100644
--- a/lib/wamp/message_handler/invocation.rb
+++ b/lib/wamp/message_handler/invocation.rb
@@ -5,6 +5,7 @@ module MessageHandler
     # Call
     class Invocation < Base
       def handle
+        connection.session.receive_message(message)
         data = store.fetch(alt_store_key)
 
         send_yield_message data.fetch(:handler)
diff --git a/lib/wamp/message_handler/publish.rb b/lib/wamp/message_handler/publish.rb
index 446f5b6..d18c49b 100644
--- a/lib/wamp/message_handler/publish.rb
+++ b/lib/wamp/message_handler/publish.rb
@@ -5,11 +5,9 @@ module MessageHandler
     # Publish message
     class Publish < Base
       def send_message(&callback)
-        send_serialized message
-
-        return unless message.options[:acknowledge]
+        store[store_key] = { callback: callback } if message.options[:acknowledge]
 
-        store[store_key] = { callback: callback }
+        send_serialized message
       end
     end
   end
diff --git a/lib/wamp/message_handler/published.rb b/lib/wamp/message_handler/published.rb
index e82ba61..f5c3386 100644
--- a/lib/wamp/message_handler/published.rb
+++ b/lib/wamp/message_handler/published.rb
@@ -5,6 +5,8 @@ module MessageHandler
     # Published confirmation message
     class Published < Base
       def handle
+        validate_received_message
+
         deliver_response
       end
     end
diff --git a/lib/wamp/message_handler/registered.rb b/lib/wamp/message_handler/registered.rb
index 4a381de..5168ace 100644
--- a/lib/wamp/message_handler/registered.rb
+++ b/lib/wamp/message_handler/registered.rb
@@ -5,6 +5,8 @@ module MessageHandler
     # Registered callback
     class Registered < Base
       def handle
+        validate_received_message
+
         store[alt_store_key] = { handler: stored_data.fetch(:handler), procedure: stored_data.fetch(:procedure) }
         store_procedure
 
diff --git a/lib/wamp/message_handler/result.rb b/lib/wamp/message_handler/result.rb
index a889590..7165cf8 100644
--- a/lib/wamp/message_handler/result.rb
+++ b/lib/wamp/message_handler/result.rb
@@ -5,6 +5,7 @@ module MessageHandler
     # Result
     class Result < Base
       def handle
+        validate_received_message
         stored_data.fetch(:handler).call(message)
       end
     end
diff --git a/lib/wamp/message_handler/subscribed.rb b/lib/wamp/message_handler/subscribed.rb
index 7ea15e3..206efb6 100644
--- a/lib/wamp/message_handler/subscribed.rb
+++ b/lib/wamp/message_handler/subscribed.rb
@@ -5,6 +5,8 @@ module MessageHandler
     # Receive subscribed
     class Subscribed < Base
       def handle
+        validate_received_message
+
         store[alt_store_key] = { handler: stored_data.fetch(:handler), topic: stored_data.fetch(:topic) }
         store_topic
 
diff --git a/lib/wamp/message_handler/unregistered.rb b/lib/wamp/message_handler/unregistered.rb
index 9a93d09..96af562 100644
--- a/lib/wamp/message_handler/unregistered.rb
+++ b/lib/wamp/message_handler/unregistered.rb
@@ -5,6 +5,8 @@ module MessageHandler
     # callback for unregister message
     class Unregistered < Base
       def handle
+        validate_received_message
+
         delete_procedure store.delete(alt_store_key)
 
         deliver_response
diff --git a/lib/wamp/message_handler/unsubscribed.rb b/lib/wamp/message_handler/unsubscribed.rb
index 5354c89..7d49b2a 100644
--- a/lib/wamp/message_handler/unsubscribed.rb
+++ b/lib/wamp/message_handler/unsubscribed.rb
@@ -5,6 +5,7 @@ module MessageHandler
     # Receive unsubscribed
     class Unsubscribed < Base
       def handle
+        validate_received_message
         delete_topic store.delete(alt_store_key)
 
         deliver_response
diff --git a/lib/wamp/message_handler/welcome.rb b/lib/wamp/message_handler/welcome.rb
new file mode 100644
index 0000000..118ed54
--- /dev/null
+++ b/lib/wamp/message_handler/welcome.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+module Wamp
+  module MessageHandler
+    # Welcome
+    class Welcome < Base
+      def handle
+        connection.executor&.call(connection.api)
+      end
+    end
+  end
+end
diff --git a/lib/wamp/message_handler/yield.rb b/lib/wamp/message_handler/yield.rb
index fcf83e6..06d67d7 100644
--- a/lib/wamp/message_handler/yield.rb
+++ b/lib/wamp/message_handler/yield.rb
@@ -3,18 +3,7 @@
 module Wamp
   module MessageHandler
     # Yield
-    class Yield
-      def initialize
-        @message = message
-        @connection = connection
-      end
-
-      def handle
-        call_request_id = connection.invocation_requests.delete(message.request_id)
-        handler = call_requests.delete(call_request_id)
-        handler.call(message)
-      end
-
+    class Yield < Base
       def send_message(handler)
         connection.transmit message
         connection.call_requests[message.request_id] = handler
diff --git a/lib/wamp/router/registrations.rb b/lib/wamp/router/registrations.rb
deleted file mode 100644
index 28246e6..0000000
--- a/lib/wamp/router/registrations.rb
+++ /dev/null
@@ -1,122 +0,0 @@
-# frozen_string_literal: true
-
-module Wamp
-  module Router
-    # Handle Procedure Registrations
-    class Registrations
-      @registrations = {}
-      @registration_ids = {}
-      class << self
-        def register(message, session)
-          return procedure_already_registered(message) if check_registered?(message)
-
-          registration_id = create_or_update_registration(message, session)
-
-          Wamp::Message::Registered.new(message.request_id, registration_id)
-        end
-
-        def check_registered?(message)
-          invocation_policy = message.options.fetch(:invoke, :single)
-          return @registrations.include?(message.procedure) if invocation_policy == "single"
-
-          registration = @registrations[message.procedure]
-          return false unless registration
-
-          return true if registration[:message].options.fetch(:invoke, :single) != invocation_policy
-
-          false
-        end
-
-        def clean_registrations(session)
-          @registrations.each_key { |procedure| clean_registration(procedure, session) }
-        end
-
-        def clean_registration(procedure, session)
-          registration = @registrations[procedure]
-          sessions = registration[:sessions]
-          if sessions.one? && sessions.include?(session)
-            puts "Removing Registration #{registration[:registration_id]}, procedure: #{procedure}"
-            @registrations.delete(procedure)
-          elsif sessions.include?(session)
-            puts "Removing Session #{session.session_id}, procedure: #{procedure}"
-            sessions.delete(session)
-          end
-        end
-
-        def clean_registration_by_id(registration_id, session)
-          procedure = @registration_ids[registration_id]
-          return unless procedure
-
-          clean_registration(procedure, session)
-        end
-
-        def create_or_update_registration(message, session)
-          registration = @registrations[message.procedure] || {}
-          registration.empty? ? create_registration(message, session) : update_registration(registration, session)
-        end
-
-        def create_registration(message, session)
-          registration_id = create_registration_id(message.procedure)
-          @registrations[message.procedure] = {
-            message: message,
-            registration_id: registration_id,
-            sessions: [session]
-          }
-          registration_id
-        end
-
-        def update_registration(registration, session)
-          registration[:sessions] << session
-          registration.fetch(:registration_id)
-        end
-
-        def invoke(message, caller_session)
-          unless @registrations.include?(message.procedure)
-            return Manager::Event.resolve(no_such_procedure(message), caller_session)
-          end
-
-          registration = @registrations.fetch(message.procedure)
-          registration_id = registration[:registration_id]
-          callee_session = find_session(registration)
-
-          Wamp::Message::Invocation.new(message.request_id * 2000, registration_id, {}, *message.args, **message.kwargs)
-            .then { |msg| Manager::Event.resolve(msg, callee_session) }
-        end
-
-        def find_session(registration)
-          sessions = registration.fetch(:sessions)
-          index = find_session_index(registration, sessions.length)
-          sessions[index]
-        end
-
-        def find_session_index(registration, session_length)
-          invocation_policy = registration.fetch(:message).options.fetch(:invoke, :single).intern
-          index = { single: 0, first: 0, last: -1, random: rand(0..(session_length - 1)) }[invocation_policy]
-          return index if index
-
-          cycle_index = registration.fetch(:cycle_index, 0)
-          registration[:cycle_index] = cycle_index < session_length - 1 ? cycle_index + 1 : 0
-          cycle_index
-        end
-
-        def procedure_already_registered(message)
-          Message::Error.new(Message::Type::REGISTER, message.request_id, {}, "wamp.error.procedure_already_exists")
-        end
-
-        def no_such_procedure(message)
-          Message::Error.new(Message::Type::CALL, message.request_id, {}, "wamp.error.no_such_procedure")
-        end
-
-        def create_registration_id(procedure)
-          id = rand(100_000..(2**53))
-          if @registration_ids.include?(id)
-            create_registration_id(procedure)
-          else
-            @registration_ids[id] = procedure
-            id
-          end
-        end
-      end
-    end
-  end
-end
diff --git a/lib/wamp/router/session/base.rb b/lib/wamp/router/session/base.rb
deleted file mode 100644
index 6260509..0000000
--- a/lib/wamp/router/session/base.rb
+++ /dev/null
@@ -1,72 +0,0 @@
-# frozen_string_literal: true
-
-module Wamp
-  module Router
-    module Session
-      # handle session establishment
-      class Base
-        REALMS = ["realm1"].freeze
-        attr_reader :hello
-
-        def initialize(hello)
-          @hello = hello
-        end
-
-        def authenticate(message)
-          return protocol_violation if message.instance_of?(Message::Hello)
-
-          return unless auth_method == "ticket"
-
-          return welcome_message if message.signature == "hello"
-
-          send_abort
-        end
-
-        def send_abort
-          Message::Abort.new({ message: "Not Authorized" }, "wamp.error.not_authorized")
-        end
-
-        def protocol_violation
-          Message::Abort.new(
-            { message: "Received HELLO message after session was established" },
-            "wamp.error.protocol_violation"
-          )
-        end
-
-        def handle_auth
-          realm = find_realm(hello.realm)
-          return realm_missing unless realm
-
-          handle_correct_auth
-        end
-
-        def handle_correct_auth
-          if auth_method == "ticket"
-            Message::Challenge.new("ticket", {})
-          else
-            welcome_message
-          end
-        end
-
-        def auth_method
-          authmethods = [*hello.details[:authmethods]]
-          authmethods.first
-        end
-
-        def welcome_message
-          Message::Welcome.new(Router.create_identifier, { roles: { broker: {} } })
-        end
-
-        def realm_missing
-          Wamp::Message::Abort.new(
-            { message: "The realm does not exists." }, "wamp.error.no_such_realm"
-          )
-        end
-
-        def find_realm(realm)
-          realm if REALMS.include?(realm)
-        end
-      end
-    end
-  end
-end