diff --git a/Example2/Chat.cs b/Example2/Chat.cs
index a87bc389..91f450ad 100644
--- a/Example2/Chat.cs
+++ b/Example2/Chat.cs
@@ -28,12 +28,12 @@ namespace Example2
 
     protected override void OnMessage (MessageEventArgs e)
     {
-      Broadcast (String.Format ("{0}: {1}", _name, e.Data));
+      Sessions.Broadcast (String.Format ("{0}: {1}", _name, e.Data));
     }
 
     protected override void OnClose (CloseEventArgs e)
     {
-      Broadcast (String.Format ("{0} got logged off...", _name));
+      Sessions.Broadcast (String.Format ("{0} got logged off...", _name));
     }
   }
 }
diff --git a/Example3/Chat.cs b/Example3/Chat.cs
index b806693c..d4036f67 100644
--- a/Example3/Chat.cs
+++ b/Example3/Chat.cs
@@ -28,12 +28,12 @@ namespace Example3
 
     protected override void OnMessage (MessageEventArgs e)
     {
-      Broadcast (String.Format ("{0}: {1}", _name, e.Data));
+      Sessions.Broadcast (String.Format ("{0}: {1}", _name, e.Data));
     }
 
     protected override void OnClose (CloseEventArgs e)
     {
-      Broadcast (String.Format ("{0} got logged off...", _name));
+      Sessions.Broadcast (String.Format ("{0} got logged off...", _name));
     }
   }
 }
diff --git a/README.md b/README.md
index fc8c4bd4..8000cefd 100644
--- a/README.md
+++ b/README.md
@@ -237,7 +237,7 @@ public class Chat : WebSocketService
 {
   protected override void OnMessage (MessageEventArgs e)
   {
-    Broadcast (e.Data);
+    Sessions.Broadcast (e.Data);
   }
 }
 ```
diff --git a/websocket-sharp/Server/IWebSocketServiceHost.cs b/websocket-sharp/Server/IWebSocketServiceHost.cs
index 02ac649c..e6b2f883 100644
--- a/websocket-sharp/Server/IWebSocketServiceHost.cs
+++ b/websocket-sharp/Server/IWebSocketServiceHost.cs
@@ -70,151 +70,5 @@ namespace WebSocketSharp.Server
     /// A <see cref="WebSocketContext"/> that contains the WebSocket connection request objects to bind.
     /// </param>
     void BindWebSocket (WebSocketContext context);
-
-    /// <summary>
-    /// Broadcasts the specified array of <see cref="byte"/> to all clients of the WebSocket service host.
-    /// </summary>
-    /// <param name="data">
-    /// An array of <see cref="byte"/> to broadcast.
-    /// </param>
-    void Broadcast (byte [] data);
-
-    /// <summary>
-    /// Broadcasts the specified <see cref="string"/> to all clients of the WebSocket service host.
-    /// </summary>
-    /// <param name="data">
-    /// A <see cref="string"/> to broadcast.
-    /// </param>
-    void Broadcast (string data);
-
-    /// <summary>
-    /// Sends Pings to all clients of the WebSocket service host.
-    /// </summary>
-    /// <returns>
-    /// A Dictionary&lt;string, bool&gt; that contains the collection of pairs of session ID and value
-    /// indicating whether the WebSocket service host received a Pong from each client in a time.
-    /// </returns>
-    Dictionary<string, bool> Broadping ();
-
-    /// <summary>
-    /// Sends Pings with the specified <paramref name="data"/> to all clients of the WebSocket service host.
-    /// </summary>
-    /// <returns>
-    /// A Dictionary&lt;string, bool&gt; that contains the collection of pairs of session ID and value
-    /// indicating whether the WebSocket service host received a Pong from each client in a time.
-    /// </returns>
-    /// <param name="data">
-    /// An array of <see cref="byte"/> that contains a message data to send.
-    /// </param>
-    Dictionary<string, bool> Broadping (byte [] data);
-
-    /// <summary>
-    /// Close the session with the specified <paramref name="id"/>.
-    /// </summary>
-    /// <param name="id">
-    /// A <see cref="string"/> that contains a session ID to find.
-    /// </param>
-    void CloseSession (string id);
-
-    /// <summary>
-    /// Close the session with the specified <paramref name="code"/>, <paramref name="reason"/>
-    /// and <paramref name="id"/>.
-    /// </summary>
-    /// <param name="code">
-    /// A <see cref="ushort"/> that contains a status code indicating the reason for closure.
-    /// </param>
-    /// <param name="reason">
-    /// A <see cref="string"/> that contains the reason for closure.
-    /// </param>
-    /// <param name="id">
-    /// A <see cref="string"/> that contains a session ID to find.
-    /// </param>
-    void CloseSession (ushort code, string reason, string id);
-
-    /// <summary>
-    /// Close the session with the specified <paramref name="code"/>, <paramref name="reason"/>
-    /// and <paramref name="id"/>.
-    /// </summary>
-    /// <param name="code">
-    /// A <see cref="CloseStatusCode"/> that contains a status code indicating the reason for closure.
-    /// </param>
-    /// <param name="reason">
-    /// A <see cref="string"/> that contains the reason for closure.
-    /// </param>
-    /// <param name="id">
-    /// A <see cref="string"/> that contains a session ID to find.
-    /// </param>
-    void CloseSession (CloseStatusCode code, string reason, string id);
-
-    /// <summary>
-    /// Sends a Ping to the client associated with the specified <paramref name="id"/>.
-    /// </summary>
-    /// <returns>
-    /// <c>true</c> if the WebSocket service host receives a Pong from the client in a time;
-    /// otherwise, <c>false</c>.
-    /// </returns>
-    /// <param name="id">
-    /// A <see cref="string"/> that contains a session ID that represents the destination for the Ping.
-    /// </param>
-    bool PingTo (string id);
-
-    /// <summary>
-    /// Sends a Ping with the specified <paramref name="message"/> to the client associated with
-    /// the specified <paramref name="id"/>.
-    /// </summary>
-    /// <returns>
-    /// <c>true</c> if the WebSocket service host receives a Pong from the client in a time;
-    /// otherwise, <c>false</c>.
-    /// </returns>
-    /// <param name="message">
-    /// A <see cref="string"/> that contains a message to send.
-    /// </param>
-    /// <param name="id">
-    /// A <see cref="string"/> that contains a session ID that represents the destination for the Ping.
-    /// </param>
-    bool PingTo (string message, string id);
-
-    /// <summary>
-    /// Sends a binary <paramref name="data"/> to the client associated with the specified
-    /// <paramref name="id"/>.
-    /// </summary>
-    /// <returns>
-    /// <c>true</c> if <paramref name="data"/> is successfully sent; otherwise, <c>false</c>.
-    /// </returns>
-    /// <param name="data">
-    /// An array of <see cref="byte"/> that contains a binary data to send.
-    /// </param>
-    /// <param name="id">
-    /// A <see cref="string"/> that contains a session ID that represents the destination for the data.
-    /// </param>
-    bool SendTo (byte [] data, string id);
-
-    /// <summary>
-    /// Sends a text <paramref name="data"/> to the client associated with the specified
-    /// <paramref name="id"/>.
-    /// </summary>
-    /// <returns>
-    /// <c>true</c> if <paramref name="data"/> is successfully sent; otherwise, <c>false</c>.
-    /// </returns>
-    /// <param name="data">
-    /// A <see cref="string"/> that contains a text data to send.
-    /// </param>
-    /// <param name="id">
-    /// A <see cref="string"/> that contains a session ID that represents the destination for the data.
-    /// </param>
-    bool SendTo (string data, string id);
-
-    /// <summary>
-    /// Stops the WebSocket service host.
-    /// </summary>
-    void Stop ();
-
-    /// <summary>
-    /// Stops the WebSocket service host with the specified array of <see cref="byte"/>.
-    /// </summary>
-    /// <param name="data">
-    /// An array of <see cref="byte"/> that contains the reason for stop.
-    /// </param>
-    void Stop (byte [] data);
   }
 }
diff --git a/websocket-sharp/Server/WebSocketService.cs b/websocket-sharp/Server/WebSocketService.cs
index 0d3f6ae7..04c15e77 100644
--- a/websocket-sharp/Server/WebSocketService.cs
+++ b/websocket-sharp/Server/WebSocketService.cs
@@ -95,8 +95,7 @@ namespace WebSocketSharp.Server
     /// Gets the manager of the sessions to the WebSocket service.
     /// </summary>
     /// <value>
-    /// A <see cref="WebSocketSessionManager"/> that manages the sessions
-    /// to the WebSocket service.
+    /// A <see cref="WebSocketSessionManager"/> that manages the sessions to the WebSocket service.
     /// </value>
     protected WebSocketSessionManager Sessions {
       get {
@@ -226,111 +225,10 @@ namespace WebSocketSharp.Server
       IsBound = true;
     }
 
-    internal bool Ping (byte [] data)
-    {
-      return _websocket.Ping (data);
-    }
-
-    internal void Stop (byte [] data)
-    {
-      _websocket.Close (data);
-    }
-
     #endregion
 
     #region Protected Methods
 
-    /// <summary>
-    /// Broadcasts the specified array of <see cref="byte"/> to all clients of the WebSocket service.
-    /// </summary>
-    /// <param name="data">
-    /// An array of <see cref="byte"/> to broadcast.
-    /// </param>
-    protected virtual void Broadcast (byte [] data)
-    {
-      if (!IsBound)
-        return;
-
-      var msg = data.CheckIfValidSendData ();
-      if (msg != null)
-      {
-        Log.Error (msg);
-        Error (msg);
-
-        return;
-      }
-
-      _sessions.Broadcast (data);
-    }
-
-    /// <summary>
-    /// Broadcasts the specified <see cref="string"/> to all clients of the WebSocket service.
-    /// </summary>
-    /// <param name="data">
-    /// A <see cref="string"/> to broadcast.
-    /// </param>
-    protected virtual void Broadcast (string data)
-    {
-      if (!IsBound)
-        return;
-
-      var msg = data.CheckIfValidSendData ();
-      if (msg != null)
-      {
-        Log.Error (msg);
-        Error (msg);
-
-        return;
-      }
-
-      _sessions.Broadcast (data);
-    }
-
-    /// <summary>
-    /// Sends Pings to all clients of the WebSocket service.
-    /// </summary>
-    /// <returns>
-    /// A Dictionary&lt;string, bool&gt; that contains the collection of pairs of session ID and value
-    /// indicating whether the WebSocket service received a Pong from each client in a time.
-    /// </returns>
-    protected virtual Dictionary<string, bool> Broadping ()
-    {
-      return IsBound
-             ? _sessions.Broadping (new byte [] {})
-             : null;
-    }
-
-    /// <summary>
-    /// Sends Pings with the specified <paramref name="message"/> to all clients of the WebSocket service.
-    /// </summary>
-    /// <returns>
-    /// A Dictionary&lt;string, bool&gt; that contains the collection of pairs of session ID and value
-    /// indicating whether the WebSocket service received a Pong from each client in a time.
-    /// </returns>
-    /// <param name="message">
-    /// A <see cref="string"/> that contains a message to send.
-    /// </param>
-    protected virtual Dictionary<string, bool> Broadping (string message)
-    {
-      if (!IsBound)
-        return null;
-
-      if (message == null || message.Length == 0)
-        return _sessions.Broadping (new byte [] {});
-
-      var data = Encoding.UTF8.GetBytes (message);
-      var msg = data.CheckIfValidPingData ();
-      if (msg != null)
-      {
-        Log.Error (msg);
-        Error (msg);
-
-        return null;
-      }
-
-      return _sessions.Broadping (data);
-    }
-
     /// <summary>
     /// Calls the <see cref="OnError"/> method with the specified <paramref name="message"/>.
     /// </summary>
@@ -384,124 +282,6 @@ namespace WebSocketSharp.Server
     {
     }
 
-    /// <summary>
-    /// Sends a Ping to the client associated with the specified <paramref name="id"/>.
-    /// </summary>
-    /// <returns>
-    /// <c>true</c> if the WebSocket service receives a Pong from the client in a time;
-    /// otherwise, <c>false</c>.
-    /// </returns>
-    /// <param name="id">
-    /// A <see cref="string"/> that contains a session ID that represents the destination for the Ping.
-    /// </param>
-    protected virtual bool PingTo (string id)
-    {
-      if (!IsBound)
-        return false;
-
-      var msg = id.CheckIfValidSessionID ();
-      if (msg != null)
-      {
-        Log.Error (msg);
-        Error (msg);
-
-        return false;
-      }
-
-      return _sessions.PingTo (id);
-    }
-
-    /// <summary>
-    /// Sends a Ping with the specified <paramref name="message"/> to the client associated with
-    /// the specified <paramref name="id"/>.
-    /// </summary>
-    /// <returns>
-    /// <c>true</c> if the WebSocket service receives a Pong from the client in a time;
-    /// otherwise, <c>false</c>.
-    /// </returns>
-    /// <param name="message">
-    /// A <see cref="string"/> that contains a message to send.
-    /// </param>
-    /// <param name="id">
-    /// A <see cref="string"/> that contains a session ID that represents the destination for the Ping.
-    /// </param>
-    protected virtual bool PingTo (string message, string id)
-    {
-      if (!IsBound)
-        return false;
-
-      var msg = id.CheckIfValidSessionID ();
-      if (msg != null)
-      {
-        Log.Error (msg);
-        Error (msg);
-
-        return false;
-      }
-
-      return _sessions.PingTo (message, id);
-    }
-
-    /// <summary>
-    /// Sends a binary <paramref name="data"/> to the client associated with the specified
-    /// <paramref name="id"/>.
-    /// </summary>
-    /// <returns>
-    /// <c>true</c> if <paramref name="data"/> is successfully sent; otherwise, <c>false</c>.
-    /// </returns>
-    /// <param name="data">
-    /// An array of <see cref="byte"/> that contains a binary data to send.
-    /// </param>
-    /// <param name="id">
-    /// A <see cref="string"/> that contains a session ID that represents the destination for the data.
-    /// </param>
-    protected virtual bool SendTo (byte [] data, string id)
-    {
-      if (!IsBound)
-        return false;
-
-      var msg = id.CheckIfValidSessionID ();
-      if (msg != null)
-      {
-        Log.Error (msg);
-        Error (msg);
-
-        return false;
-      }
-
-      return _sessions.SendTo (data, id);
-    }
-
-    /// <summary>
-    /// Sends a text <paramref name="data"/> to the client associated with the specified
-    /// <paramref name="id"/>.
-    /// </summary>
-    /// <returns>
-    /// <c>true</c> if <paramref name="data"/> is successfully sent; otherwise, <c>false</c>.
-    /// </returns>
-    /// <param name="data">
-    /// A <see cref="string"/> that contains a text data to send.
-    /// </param>
-    /// <param name="id">
-    /// A <see cref="string"/> that contains a session ID that represents the destination for the data.
-    /// </param>
-    protected virtual bool SendTo (string data, string id)
-    {
-      if (!IsBound)
-        return false;
-
-      var msg = id.CheckIfValidSessionID ();
-      if (msg != null)
-      {
-        Log.Error (msg);
-        Error (msg);
-
-        return false;
-      }
-
-      return _sessions.SendTo (data, id);
-    }
-
     /// <summary>
     /// Validates the cookies used in the WebSocket connection request.
     /// </summary>
@@ -536,7 +316,7 @@ namespace WebSocketSharp.Server
     /// <c>true</c> if the current <see cref="WebSocketService"/> instance receives a Pong
     /// from the client in a time; otherwise, <c>false</c>.
     /// </returns>
-    public virtual bool Ping ()
+    public bool Ping ()
     {
       return IsBound
              ? _websocket.Ping ()
@@ -554,7 +334,7 @@ namespace WebSocketSharp.Server
     /// <param name="message">
     /// A <see cref="string"/> that contains a message to send.
     /// </param>
-    public virtual bool Ping (string message)
+    public bool Ping (string message)
     {
       return IsBound
              ? _websocket.Ping (message)
diff --git a/websocket-sharp/Server/WebSocketServiceHost.cs b/websocket-sharp/Server/WebSocketServiceHost.cs
index f74855e5..65c8dbab 100644
--- a/websocket-sharp/Server/WebSocketServiceHost.cs
+++ b/websocket-sharp/Server/WebSocketServiceHost.cs
@@ -315,246 +315,6 @@ namespace WebSocketSharp.Server
 
     #region Public Methods
 
-    /// <summary>
-    /// Broadcasts the specified array of <see cref="byte"/> to all clients.
-    /// </summary>
-    /// <param name="data">
-    /// An array of <see cref="byte"/> to broadcast.
-    /// </param>
-    public void Broadcast (byte [] data)
-    {
-      var msg = data.CheckIfValidSendData ();
-      if (msg != null)
-      {
-        Log.Error (msg);
-        return;
-      }
-
-      _sessions.Broadcast (data);
-    }
-
-    /// <summary>
-    /// Broadcasts the specified <see cref="string"/> to all clients.
-    /// </summary>
-    /// <param name="data">
-    /// A <see cref="string"/> to broadcast.
-    /// </param>
-    public void Broadcast (string data)
-    {
-      var msg = data.CheckIfValidSendData ();
-      if (msg != null)
-      {
-        Log.Error (msg);
-        return;
-      }
-
-      _sessions.Broadcast (data);
-    }
-
-    /// <summary>
-    /// Sends Pings to all clients.
-    /// </summary>
-    /// <returns>
-    /// A Dictionary&lt;string, bool&gt; that contains the collection of pairs of session ID and value
-    /// indicating whether the WebSocket service host received a Pong from each client in a time.
-    /// </returns>
-    public Dictionary<string, bool> Broadping ()
-    {
-      return _sessions.Broadping (new byte [] {});
-    }
-
-    /// <summary>
-    /// Sends Pings with the specified <paramref name="message"/> to all clients.
-    /// </summary>
-    /// <returns>
-    /// A Dictionary&lt;string, bool&gt; that contains the collection of pairs of session ID and value
-    /// indicating whether the WebSocket service host received a Pong from each client in a time.
-    /// </returns>
-    /// <param name="message">
-    /// A <see cref="string"/> that contains a message to send.
-    /// </param>
-    public Dictionary<string, bool> Broadping (string message)
-    {
-      if (message == null || message.Length == 0)
-        return _sessions.Broadping (new byte [] {});
-
-      var data = Encoding.UTF8.GetBytes (message);
-      var msg = data.CheckIfValidPingData ();
-      if (msg != null)
-      {
-        Log.Error (msg);
-        return null;
-      }
-
-      return _sessions.Broadping (data);
-    }
-
-    /// <summary>
-    /// Close the session with the specified <paramref name="id"/>.
-    /// </summary>
-    /// <param name="id">
-    /// A <see cref="string"/> that contains a session ID to find.
-    /// </param>
-    public void CloseSession (string id)
-    {
-      var msg = id.CheckIfValidSessionID ();
-      if (msg != null)
-      {
-        Log.Error (msg);
-        return;
-      }
-
-      _sessions.StopServiceInstance (id);
-    }
-
-    /// <summary>
-    /// Close the session with the specified <paramref name="code"/>, <paramref name="reason"/>
-    /// and <paramref name="id"/>.
-    /// </summary>
-    /// <param name="code">
-    /// A <see cref="ushort"/> that contains a status code indicating the reason for closure.
-    /// </param>
-    /// <param name="reason">
-    /// A <see cref="string"/> that contains the reason for closure.
-    /// </param>
-    /// <param name="id">
-    /// A <see cref="string"/> that contains a session ID to find.
-    /// </param>
-    public void CloseSession (ushort code, string reason, string id)
-    {
-      var msg = id.CheckIfValidSessionID ();
-      if (msg != null)
-      {
-        Log.Error (msg);
-        return;
-      }
-
-      _sessions.StopServiceInstance (code, reason, id);
-    }
-
-    /// <summary>
-    /// Close the session with the specified <paramref name="code"/>, <paramref name="reason"/>
-    /// and <paramref name="id"/>.
-    /// </summary>
-    /// <param name="code">
-    /// A <see cref="CloseStatusCode"/> that contains a status code indicating the reason for closure.
-    /// </param>
-    /// <param name="reason">
-    /// A <see cref="string"/> that contains the reason for closure.
-    /// </param>
-    /// <param name="id">
-    /// A <see cref="string"/> that contains a session ID to find.
-    /// </param>
-    public void CloseSession (CloseStatusCode code, string reason, string id)
-    {
-      var msg = id.CheckIfValidSessionID ();
-      if (msg != null)
-      {
-        Log.Error (msg);
-        return;
-      }
-
-      _sessions.StopServiceInstance (code, reason, id);
-    }
-
-    /// <summary>
-    /// Sends a Ping to the client associated with the specified <paramref name="id"/>.
-    /// </summary>
-    /// <returns>
-    /// <c>true</c> if the WebSocket service host receives a Pong from the client in a time;
-    /// otherwise, <c>false</c>.
-    /// </returns>
-    /// <param name="id">
-    /// A <see cref="string"/> that contains a session ID that represents the destination for the Ping.
-    /// </param>
-    public bool PingTo (string id)
-    {
-      var msg = id.CheckIfValidSessionID ();
-      if (msg != null)
-      {
-        Log.Error (msg);
-        return false;
-      }
-
-      return _sessions.PingTo (id);
-    }
-
-    /// <summary>
-    /// Sends a Ping with the specified <paramref name="message"/> to the client associated with
-    /// the specified <paramref name="id"/>.
-    /// </summary>
-    /// <returns>
-    /// <c>true</c> if the WebSocket service host receives a Pong from the client in a time;
-    /// otherwise, <c>false</c>.
-    /// </returns>
-    /// <param name="message">
-    /// A <see cref="string"/> that contains a message to send.
-    /// </param>
-    /// <param name="id">
-    /// A <see cref="string"/> that contains a session ID that represents the destination for the Ping.
-    /// </param>
-    public bool PingTo (string message, string id)
-    {
-      var msg = id.CheckIfValidSessionID ();
-      if (msg != null)
-      {
-        Log.Error (msg);
-        return false;
-      }
-
-      return _sessions.PingTo (message, id);
-    }
-
-    /// <summary>
-    /// Sends a binary <paramref name="data"/> to the client associated with the specified
-    /// <paramref name="id"/>.
-    /// </summary>
-    /// <returns>
-    /// <c>true</c> if <paramref name="data"/> is successfully sent; otherwise, <c>false</c>.
-    /// </returns>
-    /// <param name="data">
-    /// An array of <see cref="byte"/> that contains a binary data to send.
-    /// </param>
-    /// <param name="id">
-    /// A <see cref="string"/> that contains a session ID that represents the destination for the data.
-    /// </param>
-    public bool SendTo (byte [] data, string id)
-    {
-      var msg = id.CheckIfValidSessionID ();
-      if (msg != null)
-      {
-        Log.Error (msg);
-        return false;
-      }
-
-      return _sessions.SendTo (data, id);
-    }
-
-    /// <summary>
-    /// Sends a text <paramref name="data"/> to the client associated with the specified
-    /// <paramref name="id"/>.
-    /// </summary>
-    /// <returns>
-    /// <c>true</c> if <paramref name="data"/> is successfully sent; otherwise, <c>false</c>.
-    /// </returns>
-    /// <param name="data">
-    /// A <see cref="string"/> that contains a text data to send.
-    /// </param>
-    /// <param name="id">
-    /// A <see cref="string"/> that contains a session ID that represents the destination for the data.
-    /// </param>
-    public bool SendTo (string data, string id)
-    {
-      var msg = id.CheckIfValidSessionID ();
-      if (msg != null)
-      {
-        Log.Error (msg);
-        return false;
-      }
-
-      return _sessions.SendTo (data, id);
-    }
-
     /// <summary>
     /// Stops receiving the WebSocket connection requests.
     /// </summary>
@@ -618,55 +378,6 @@ namespace WebSocketSharp.Server
       service.Start ();
     }
 
-    /// <summary>
-    /// Broadcasts the specified array of <see cref="byte"/> to all clients.
-    /// </summary>
-    /// <param name="data">
-    /// An array of <see cref="byte"/> to broadcast.
-    /// </param>
-    void IWebSocketServiceHost.Broadcast (byte [] data)
-    {
-      _sessions.Broadcast (data);
-    }
-
-    /// <summary>
-    /// Broadcasts the specified <see cref="string"/> to all clients.
-    /// </summary>
-    /// <param name="data">
-    /// A <see cref="string"/> to broadcast.
-    /// </param>
-    void IWebSocketServiceHost.Broadcast (string data)
-    {
-      _sessions.Broadcast (data);
-    }
-
-    /// <summary>
-    /// Sends Pings with the specified <paramref name="data"/> to all clients.
-    /// </summary>
-    /// <returns>
-    /// A Dictionary&lt;string, bool&gt; that contains the collection of pairs of session ID and value
-    /// indicating whether the WebSocket service host received a Pong from each client in a time.
-    /// </returns>
-    /// <param name="data">
-    /// An array of <see cref="byte"/> that contains a message data to send.
-    /// </param>
-    Dictionary<string, bool> IWebSocketServiceHost.Broadping (byte [] data)
-    {
-      return _sessions.Broadping (data);
-    }
-
-    /// <summary>
-    /// Stops receiving the WebSocket connection requests with the specified array of <see cref="byte"/>.
-    /// </summary>
-    /// <param name="data">
-    /// An array of <see cref="byte"/> that contains the reason for stop.
-    /// </param>
-    void IWebSocketServiceHost.Stop (byte [] data)
-    {
-      base.Stop ();
-      _sessions.Stop (data);
-    }
-
     #endregion
   }
 }
diff --git a/websocket-sharp/Server/WebSocketServiceHostManager.cs b/websocket-sharp/Server/WebSocketServiceHostManager.cs
index adbeb296..dad24bcc 100644
--- a/websocket-sharp/Server/WebSocketServiceHostManager.cs
+++ b/websocket-sharp/Server/WebSocketServiceHostManager.cs
@@ -131,10 +131,10 @@ namespace WebSocketSharp.Server
     }
 
     /// <summary>
-    /// Gets the collection of each path to the WebSocket services provided by the WebSocket server.
+    /// Gets the collection of every path to the WebSocket services provided by the WebSocket server.
     /// </summary>
     /// <value>
-    /// An IEnumerable&lt;string&gt; that contains the collection of each path to the WebSocket services.
+    /// An IEnumerable&lt;string&gt; that contains the collection of every path to the WebSocket services.
     /// </value>
     public IEnumerable<string> ServicePaths {
       get {
@@ -149,6 +149,15 @@ namespace WebSocketSharp.Server
 
     #region Private Methods
 
+    private Dictionary<string, Dictionary<string, bool>> broadping (byte [] data)
+    {
+      var result = new Dictionary<string, Dictionary<string, bool>> ();
+      foreach (var service in copy ())
+        result.Add (service.Key, service.Value.Sessions.BroadpingInternally (data));
+
+      return result;
+    }
+
     private Dictionary<string, IWebSocketServiceHost> copy ()
     {
       lock (_sync)
@@ -178,15 +187,6 @@ namespace WebSocketSharp.Server
       }
     }
 
-    internal Dictionary<string, Dictionary<string, bool>> Broadping (byte [] data)
-    {
-      var result = new Dictionary<string, Dictionary<string, bool>> ();
-      foreach (var service in copy ())
-        result.Add (service.Key, service.Value.Broadping (data));
-
-      return result;
-    }
-
     internal bool Remove (string servicePath)
     {
       servicePath = HttpUtility.UrlDecode (servicePath).TrimEndSlash ();
@@ -204,7 +204,7 @@ namespace WebSocketSharp.Server
         _serviceHosts.Remove (servicePath);
       }
 
-      host.Stop (((ushort) CloseStatusCode.AWAY).ToByteArray (ByteOrder.BIG));
+      host.Sessions.Stop (((ushort) CloseStatusCode.AWAY).ToByteArray (ByteOrder.BIG));
       return true;
     }
 
@@ -213,7 +213,7 @@ namespace WebSocketSharp.Server
       lock (_sync)
       {
         foreach (var host in _serviceHosts.Values)
-          host.Stop ();
+          host.Sessions.Stop ();
 
         _serviceHosts.Clear ();
       }
@@ -224,7 +224,7 @@ namespace WebSocketSharp.Server
       lock (_sync)
       {
         foreach (var host in _serviceHosts.Values)
-          host.Stop (data);
+          host.Sessions.Stop (data);
 
         _serviceHosts.Clear ();
       }
@@ -260,7 +260,7 @@ namespace WebSocketSharp.Server
       }
 
       foreach (var host in ServiceHosts)
-        host.Broadcast (data);
+        host.Sessions.BroadcastInternally (data);
     }
 
     /// <summary>
@@ -280,7 +280,7 @@ namespace WebSocketSharp.Server
       }
 
       foreach (var host in ServiceHosts)
-        host.Broadcast (data);
+        host.Sessions.BroadcastInternally (data);
     }
 
     /// <summary>
@@ -312,7 +312,7 @@ namespace WebSocketSharp.Server
         return false;
       }
 
-      host.Broadcast (data);
+      host.Sessions.BroadcastInternally (data);
       return true;
     }
 
@@ -345,7 +345,7 @@ namespace WebSocketSharp.Server
         return false;
       }
 
-      host.Broadcast (data);
+      host.Sessions.BroadcastInternally (data);
       return true;
     }
 
@@ -359,7 +359,7 @@ namespace WebSocketSharp.Server
     /// </returns>
     public Dictionary<string, Dictionary<string, bool>> Broadping ()
     {
-      return Broadping (new byte [] {});
+      return broadping (new byte [] {});
     }
 
     /// <summary>
@@ -378,7 +378,7 @@ namespace WebSocketSharp.Server
     public Dictionary<string, Dictionary<string, bool>> Broadping (string message)
     {
       if (message == null || message.Length == 0)
-        return Broadping (new byte [] {});
+        return broadping (new byte [] {});
 
       var data = Encoding.UTF8.GetBytes (message);
       var msg = data.CheckIfValidPingData ();
@@ -388,7 +388,7 @@ namespace WebSocketSharp.Server
         return null;
       }
 
-      return Broadping (data);
+      return broadping (data);
     }
 
     /// <summary>
@@ -418,7 +418,7 @@ namespace WebSocketSharp.Server
         return null;
       }
 
-      return host.Broadping (new byte [] {});
+      return host.Sessions.BroadpingInternally (new byte [] {});
     }
 
     /// <summary>
@@ -456,11 +456,11 @@ namespace WebSocketSharp.Server
         return null;
       }
 
-      return host.Broadping (data);
+      return host.Sessions.BroadpingInternally (data);
     }
 
     /// <summary>
-    /// Close the session with the specified <paramref name="id"/> and
+    /// Closes the session with the specified <paramref name="id"/> and
     /// <paramref name="servicePath"/>.
     /// </summary>
     /// <param name="id">
@@ -485,11 +485,11 @@ namespace WebSocketSharp.Server
         return;
       }
 
-      host.CloseSession (id);
+      host.Sessions.CloseSession (id);
     }
 
     /// <summary>
-    /// Close the session with the specified <paramref name="code"/>, <paramref name="reason"/>,
+    /// Closes the session with the specified <paramref name="code"/>, <paramref name="reason"/>,
     /// <paramref name="id"/> and <paramref name="servicePath"/>.
     /// </summary>
     /// <param name="code">
@@ -520,11 +520,11 @@ namespace WebSocketSharp.Server
         return;
       }
 
-      host.CloseSession (code, reason, id);
+      host.Sessions.CloseSession (code, reason, id);
     }
 
     /// <summary>
-    /// Close the session with the specified <paramref name="code"/>, <paramref name="reason"/>,
+    /// Closes the session with the specified <paramref name="code"/>, <paramref name="reason"/>,
     /// <paramref name="id"/> and <paramref name="servicePath"/>.
     /// </summary>
     /// <param name="code">
@@ -555,7 +555,7 @@ namespace WebSocketSharp.Server
         return;
       }
 
-      host.CloseSession (code, reason, id);
+      host.Sessions.CloseSession (code, reason, id);
     }
 
     /// <summary>
@@ -646,7 +646,7 @@ namespace WebSocketSharp.Server
         return false;
       }
 
-      return host.PingTo (id);
+      return host.Sessions.PingTo (id);
     }
 
     /// <summary>
@@ -682,7 +682,7 @@ namespace WebSocketSharp.Server
         return false;
       }
 
-      return host.PingTo (message, id);
+      return host.Sessions.PingTo (message, id);
     }
 
     /// <summary>
@@ -717,7 +717,7 @@ namespace WebSocketSharp.Server
         return false;
       }
 
-      return host.SendTo (data, id);
+      return host.Sessions.SendTo (data, id);
     }
 
     /// <summary>
@@ -752,7 +752,7 @@ namespace WebSocketSharp.Server
         return false;
       }
 
-      return host.SendTo (data, id);
+      return host.Sessions.SendTo (data, id);
     }
 
     #endregion
diff --git a/websocket-sharp/Server/WebSocketSessionManager.cs b/websocket-sharp/Server/WebSocketSessionManager.cs
index 8b912a1c..a9f72261 100644
--- a/websocket-sharp/Server/WebSocketSessionManager.cs
+++ b/websocket-sharp/Server/WebSocketSessionManager.cs
@@ -29,6 +29,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Text;
 using System.Timers;
 
 namespace WebSocketSharp.Server
@@ -95,7 +96,7 @@ namespace WebSocketSharp.Server
     /// </value>
     public IEnumerable<string> ActiveIDs {
       get {
-        return from result in Broadping (new byte [] {})
+        return from result in BroadpingInternally (new byte [] {})
                where result.Value
                select result.Key;
       }
@@ -139,7 +140,7 @@ namespace WebSocketSharp.Server
     /// </value>
     public IEnumerable<string> InactiveIDs {
       get {
-        return from result in Broadping (new byte [] {})
+        return from result in BroadpingInternally (new byte [] {})
                where !result.Value
                select result.Key;
       }
@@ -170,7 +171,8 @@ namespace WebSocketSharp.Server
             return _sessions [id];
           }
           catch {
-            _logger.Error ("'id' not found.\nid: " + id);
+            _logger.Error (
+              "The WebSocket session with the specified ID not found.\nID: " + id);
             return null;
           }
         }
@@ -301,7 +303,7 @@ namespace WebSocketSharp.Server
       }
     }
 
-    internal void Broadcast (byte [] data)
+    internal void BroadcastInternally (byte [] data)
     {
       if (_stopped)
         broadcast (data);
@@ -309,7 +311,7 @@ namespace WebSocketSharp.Server
         broadcastAsync (data);
     }
 
-    internal void Broadcast (string data)
+    internal void BroadcastInternally (string data)
     {
       if (_stopped)
         broadcast (data);
@@ -317,155 +319,360 @@ namespace WebSocketSharp.Server
         broadcastAsync (data);
     }
 
-    internal Dictionary<string, bool> Broadping (byte [] data)
+    internal Dictionary<string, bool> BroadpingInternally (byte [] data)
     {
       var result = new Dictionary<string, bool> ();
-      foreach (var service in ServiceInstances)
-        result.Add (service.ID, service.Ping (data));
+      foreach (var session in ServiceInstances)
+        result.Add (session.ID, session.Context.WebSocket.Ping (data));
 
       return result;
     }
 
-    internal bool PingTo (string id)
+    internal bool Remove (string id)
     {
-      WebSocketService service;
-      if (!TryGetServiceInstance (id, out service))
+      lock (_sync)
       {
-        _logger.Error (
-          "The WebSocket session with the specified ID not found.\nID: " + id);
-        return false;
+        return _sessions.Remove (id);
       }
-
-      return service.Ping ();
     }
 
-    internal bool PingTo (string message, string id)
+    internal void Stop ()
     {
-      WebSocketService service;
-      if (!TryGetServiceInstance (id, out service))
+      stopSweepTimer ();
+      lock (_sync)
       {
-        _logger.Error (
-          "The WebSocket session with the specified ID not found.\nID: " + id);
-        return false;
+        if (_stopped)
+          return;
+
+        _stopped = true;
+        foreach (var session in ServiceInstances)
+          session.Context.WebSocket.Close ();
       }
+    }
+
+    internal void Stop (byte [] data)
+    {
+      stopSweepTimer ();
+      lock (_sync)
+      {
+        if (_stopped)
+          return;
 
-      return service.Ping (message);
+        _stopped = true;
+        foreach (var session in ServiceInstances)
+          session.Context.WebSocket.Close (data);
+      }
     }
 
-    internal bool Remove (string id)
+    internal bool TryGetServiceInstance (string id, out WebSocketService service)
     {
       lock (_sync)
       {
-        return _sessions.Remove (id);
+        return _sessions.TryGetValue (id, out service);
       }
     }
 
-    internal bool SendTo (byte [] data, string id)
+    #endregion
+
+    #region Public Methods
+
+    /// <summary>
+    /// Broadcasts the specified array of <see cref="byte"/> to all clients of the WebSocket service.
+    /// </summary>
+    /// <param name="data">
+    /// An array of <see cref="byte"/> to broadcast.
+    /// </param>
+    public void Broadcast (byte [] data)
     {
-      WebSocketService service;
-      if (!TryGetServiceInstance (id, out service))
+      var msg = data.CheckIfValidSendData ();
+      if (msg != null)
       {
-        _logger.Error (
-          "The WebSocket session with the specified ID not found.\nID: " + id);
-        return false;
+        _logger.Error (msg);
+        return;
       }
 
-      service.Send (data);
-      return true;
+      BroadcastInternally (data);
     }
 
-    internal bool SendTo (string data, string id)
+    /// <summary>
+    /// Broadcasts the specified <see cref="string"/> to all clients of the WebSocket service.
+    /// </summary>
+    /// <param name="data">
+    /// A <see cref="string"/> to broadcast.
+    /// </param>
+    public void Broadcast (string data)
     {
-      WebSocketService service;
-      if (!TryGetServiceInstance (id, out service))
+      var msg = data.CheckIfValidSendData ();
+      if (msg != null)
+      {
+        _logger.Error (msg);
+        return;
+      }
+
+      BroadcastInternally (data);
+    }
+
+    /// <summary>
+    /// Sends Pings to all clients of the WebSocket service.
+    /// </summary>
+    /// <returns>
+    /// A Dictionary&lt;string, bool&gt; that contains the collection of pairs of session ID and value
+    /// indicating whether the WebSocket service received a Pong from each client in a time.
+    /// </returns>
+    public Dictionary<string, bool> Broadping ()
+    {
+      return BroadpingInternally (new byte [] {});
+    }
+
+    /// <summary>
+    /// Sends Pings with the specified <paramref name="message"/> to all clients of the WebSocket service.
+    /// </summary>
+    /// <returns>
+    /// A Dictionary&lt;string, bool&gt; that contains the collection of pairs of session ID and value
+    /// indicating whether the WebSocket service received a Pong from each client in a time.
+    /// </returns>
+    /// <param name="message">
+    /// A <see cref="string"/> that contains a message to send.
+    /// </param>
+    public Dictionary<string, bool> Broadping (string message)
+    {
+      if (message == null || message.Length == 0)
+        return BroadpingInternally (new byte [] {});
+
+      var data = Encoding.UTF8.GetBytes (message);
+      var msg = data.CheckIfValidPingData ();
+      if (msg != null)
+      {
+        _logger.Error (msg);
+        return null;
+      }
+
+      return BroadpingInternally (data);
+    }
+
+    /// <summary>
+    /// Closes the session with the specified <paramref name="id"/>.
+    /// </summary>
+    /// <param name="id">
+    /// A <see cref="string"/> that contains a session ID to find.
+    /// </param>
+    public void CloseSession (string id)
+    {
+      var msg = id.CheckIfValidSessionID ();
+      if (msg != null)
+      {
+        _logger.Error (msg);
+        return;
+      }
+
+      WebSocketService session;
+      if (!TryGetServiceInstance (id, out session))
       {
         _logger.Error (
           "The WebSocket session with the specified ID not found.\nID: " + id);
-        return false;
+        return;
       }
 
-      service.Send (data);
-      return true;
+      session.Context.WebSocket.Close ();
     }
 
-    internal void Stop ()
+    /// <summary>
+    /// Closes the session with the specified <paramref name="code"/>, <paramref name="reason"/>
+    /// and <paramref name="id"/>.
+    /// </summary>
+    /// <param name="code">
+    /// A <see cref="ushort"/> that contains a status code indicating the reason for closure.
+    /// </param>
+    /// <param name="reason">
+    /// A <see cref="string"/> that contains the reason for closure.
+    /// </param>
+    /// <param name="id">
+    /// A <see cref="string"/> that contains a session ID to find.
+    /// </param>
+    public void CloseSession (ushort code, string reason, string id)
     {
-      stopSweepTimer ();
-      lock (_sync)
+      var msg = id.CheckIfValidSessionID ();
+      if (msg != null)
       {
-        if (_stopped)
-          return;
+        _logger.Error (msg);
+        return;
+      }
 
-        _stopped = true;
-        foreach (var service in ServiceInstances)
-          service.Stop ();
+      WebSocketService session;
+      if (!TryGetServiceInstance (id, out session))
+      {
+        _logger.Error (
+          "The WebSocket session with the specified ID not found.\nID: " + id);
+        return;
       }
+
+      session.Context.WebSocket.Close (code, reason);
     }
 
-    internal void Stop (byte [] data)
+    /// <summary>
+    /// Closes the session with the specified <paramref name="code"/>, <paramref name="reason"/>
+    /// and <paramref name="id"/>.
+    /// </summary>
+    /// <param name="code">
+    /// A <see cref="CloseStatusCode"/> that contains a status code indicating the reason for closure.
+    /// </param>
+    /// <param name="reason">
+    /// A <see cref="string"/> that contains the reason for closure.
+    /// </param>
+    /// <param name="id">
+    /// A <see cref="string"/> that contains a session ID to find.
+    /// </param>
+    public void CloseSession (CloseStatusCode code, string reason, string id)
     {
-      stopSweepTimer ();
-      lock (_sync)
+      var msg = id.CheckIfValidSessionID ();
+      if (msg != null)
       {
-        if (_stopped)
-          return;
+        _logger.Error (msg);
+        return;
+      }
 
-        _stopped = true;
-        foreach (var service in ServiceInstances)
-          service.Stop (data);
+      WebSocketService session;
+      if (!TryGetServiceInstance (id, out session))
+      {
+        _logger.Error (
+          "The WebSocket session with the specified ID not found.\nID: " + id);
+        return;
       }
+
+      session.Context.WebSocket.Close (code, reason);
     }
 
-    internal void StopServiceInstance (string id)
+    /// <summary>
+    /// Sends a Ping to the client associated with the specified <paramref name="id"/>.
+    /// </summary>
+    /// <returns>
+    /// <c>true</c> if the WebSocket service receives a Pong from the client in a time;
+    /// otherwise, <c>false</c>.
+    /// </returns>
+    /// <param name="id">
+    /// A <see cref="string"/> that contains a session ID that represents the destination for the Ping.
+    /// </param>
+    public bool PingTo (string id)
     {
-      WebSocketService service;
-      if (!TryGetServiceInstance (id, out service))
+      var msg = id.CheckIfValidSessionID ();
+      if (msg != null)
+      {
+        _logger.Error (msg);
+        return false;
+      }
+
+      WebSocketService session;
+      if (!TryGetServiceInstance (id, out session))
       {
         _logger.Error (
           "The WebSocket session with the specified ID not found.\nID: " + id);
-        return;
+        return false;
       }
 
-      service.Stop ();
+      return session.Context.WebSocket.Ping ();
     }
 
-    internal void StopServiceInstance (ushort code, string reason, string id)
+    /// <summary>
+    /// Sends a Ping with the specified <paramref name="message"/> to the client associated with
+    /// the specified <paramref name="id"/>.
+    /// </summary>
+    /// <returns>
+    /// <c>true</c> if the WebSocket service receives a Pong from the client in a time;
+    /// otherwise, <c>false</c>.
+    /// </returns>
+    /// <param name="message">
+    /// A <see cref="string"/> that contains a message to send.
+    /// </param>
+    /// <param name="id">
+    /// A <see cref="string"/> that contains a session ID that represents the destination for the Ping.
+    /// </param>
+    public bool PingTo (string message, string id)
     {
-      WebSocketService service;
-      if (!TryGetServiceInstance (id, out service))
+      var msg = id.CheckIfValidSessionID ();
+      if (msg != null)
+      {
+        _logger.Error (msg);
+        return false;
+      }
+
+      WebSocketService session;
+      if (!TryGetServiceInstance (id, out session))
       {
         _logger.Error (
           "The WebSocket session with the specified ID not found.\nID: " + id);
-        return;
+        return false;
       }
 
-      service.Stop (code, reason);
+      return session.Context.WebSocket.Ping (message);
     }
 
-    internal void StopServiceInstance (CloseStatusCode code, string reason, string id)
+    /// <summary>
+    /// Sends a binary <paramref name="data"/> to the client associated with the specified
+    /// <paramref name="id"/>.
+    /// </summary>
+    /// <returns>
+    /// <c>true</c> if <paramref name="data"/> is successfully sent; otherwise, <c>false</c>.
+    /// </returns>
+    /// <param name="data">
+    /// An array of <see cref="byte"/> that contains a binary data to send.
+    /// </param>
+    /// <param name="id">
+    /// A <see cref="string"/> that contains a session ID that represents the destination for the data.
+    /// </param>
+    public bool SendTo (byte [] data, string id)
     {
+      var msg = id.CheckIfValidSessionID ();
+      if (msg != null)
+      {
+        _logger.Error (msg);
+        return false;
+      }
+
       WebSocketService service;
       if (!TryGetServiceInstance (id, out service))
       {
         _logger.Error (
           "The WebSocket session with the specified ID not found.\nID: " + id);
-        return;
+        return false;
       }
 
-      service.Stop (code, reason);
+      service.Send (data);
+      return true;
     }
 
-    internal bool TryGetServiceInstance (string id, out WebSocketService service)
+    /// <summary>
+    /// Sends a text <paramref name="data"/> to the client associated with the specified
+    /// <paramref name="id"/>.
+    /// </summary>
+    /// <returns>
+    /// <c>true</c> if <paramref name="data"/> is successfully sent; otherwise, <c>false</c>.
+    /// </returns>
+    /// <param name="data">
+    /// A <see cref="string"/> that contains a text data to send.
+    /// </param>
+    /// <param name="id">
+    /// A <see cref="string"/> that contains a session ID that represents the destination for the data.
+    /// </param>
+    public bool SendTo (string data, string id)
     {
-      lock (_sync)
+      var msg = id.CheckIfValidSessionID ();
+      if (msg != null)
       {
-        return _sessions.TryGetValue (id, out service);
+        _logger.Error (msg);
+        return false;
       }
-    }
 
-    #endregion
+      WebSocketService service;
+      if (!TryGetServiceInstance (id, out service))
+      {
+        _logger.Error (
+          "The WebSocket session with the specified ID not found.\nID: " + id);
+        return false;
+      }
 
-    #region Public Methods
+      service.Send (data);
+      return true;
+    }
 
     /// <summary>
     /// Cleans up the inactive sessions.
@@ -490,7 +697,7 @@ namespace WebSocketSharp.Server
             {
               var state = service.State;
               if (state == WebSocketState.OPEN)
-                service.Stop (((ushort) CloseStatusCode.ABNORMAL).ToByteArray (ByteOrder.BIG));
+                service.Context.WebSocket.Close (CloseStatusCode.ABNORMAL);
               else if (state == WebSocketState.CLOSING)
                 continue;
               else