How to make/simulate persistent TCP connection?

Question

It looks like WCF TCP connections are not persistent. First ping reply takes a while but subsequent processes take less time. After a while it takes long again -another re-connection?

SERVER> Started on net.tcp://0.0.0.0:999

CLIENT> Connection created to net.tcp://localhost:999 //Not a real connection, ready to connect

CLIENT> Ping reply in 1s163ms //First connection

CLIENT> Ping reply in 22ms //Already connected

CLIENT> Ping reply in 26ms

CLIENT> Ping reply in 24ms

CLIENT> Ping reply in 325ms //Re-connected

CLIENT> Ping reply in 19ms

CLIENT> Ping reply in 767ms //Re-connected

If it's true, what is the idle time value for a tcp connection before it will be disconnected? I need to keep the connection alive.

Update Modified code:

NetTcpBinding tcpBind = new NetTcpBinding();
tcpBind.ReliableSession.Enabled = true;
tcpBind.ReliableSession.Ordered = true;
tcpBind.ReliableSession.InactivityTimeout = TimeSpan.FromMinutes(10);

ServiceHost svh = new ServiceHost(typeof(ServiceImplementation));
svh.AddServiceEndpoint(
    typeof(WCFSimple.Contract.IService),
    //new NetTcpBinding(),
    tcpBind,
    String.Format("net.tcp://{0}:{1}", ip, port));
svh.Open();

Now I got another error:

The action http://tempuri.org/IService/Pong is not supported by this endpoint. Only WS-ReliableMessaging February 2005 messages are processed by this endpoint.

Update I modified only server side and it caused the error. Then I modified client side's TCP as reliable messaging.

Answer 1

I don't think Ping is a good tool to test a TCP connection. Because Ping uses ICMP as its underlying protocol instead of TCP.

I suggest you create a WCF client, connect to the service and then check the TCP connection via some network sniffering tools or simply use netstat for quick check.