TimeoutException thrown by a WCF client proxy

My question is related to a System.TimeoutException that is thrown by WCF from time to time:

System.TimeoutException: The open operation did not complete within the allotted timeout of 00:00:00. The time allotted to this operation may have been a portion of a longer timeout. ---> System.TimeoutException: Open timed out after 00:00:00 while establishing a transport session to net.tcp://192.168.1.100:50000/TabletSvc/. The time allotted to this operation may have been a portion of a longer timeout. ---> System.TimeoutException: Connecting to via net.tcp://192.168.1.100:50000/TabletSvc/ timed out after 00:00:00. Connection attempts were made to 0 of 1 available addresses (). Check the RemoteAddress of your channel and verify that the DNS records for this endpoint correspond to valid IP Addresses. The time allotted to this operation may have been a portion of a longer timeout.

What are the possible causes for random behavior?

The WCF service is hosted into a .NET application running on Windows XP SP2. The application creates a client proxy to same service hosted on a different machine. One important aspect is that the service is using reliableSession and serviceThrottling. The machines are communicating through a WiFi connection.

The client and the service are on separate threads inside the same application. From this point of view they do not depend on each other. There should be no locking.

I checked the WiFi connectivity between machines using ping and it appears to be fine. The next step would be to put in place a network monitor, but since they are production machines it might not happen soon.

I thought about increasing both maxConcurrentSessions and maxConcurrentInstances to 50 but haven't got the time to test it. This is based on the idea that maybe the application is running out of resources or reaches a limit which impacts the hosted service.

As I said, the client proxy fails to open a connection only from time to time. A second attempt a minute later usually succeeds.

Here is the client and service configuration:

<system.serviceModel>
<client>
  <endpoint name="TabletSvcEndpoint" address="net.tcp://localhost:50000/TabletSvc/" binding="netTcpBinding" bindingConfiguration="TabletSvcBinding" contract="ITabletSvc">
   <identity>
    <dns value="localhost" />
   </identity>
  </endpoint>
</client>

<services>
 <service behaviorConfiguration="TabletSvcBehavior" name="TabletSvc">
   <endpoint name="TabletSvcEndpoint" address="" binding="netTcpBinding" bindingConfiguration="TabletSvcBinding" contract="ITabletSvc">
    <identity>
     <dns value="localhost" />
    </identity>
   </endpoint>
   <host>
    <baseAddresses>
     <add baseAddress="net.tcp://localhost:50000/TabletSvc/" />
        </baseAddresses>
   </host>
 </service>
</services>

<bindings>
 <netTcpBinding>
   <binding name="TabletSvcBinding" receiveTimeout="00:30:00" sendTimeout="00:00:30" closeTimeout="00:00:05" openTimeout="00:00:05" transactionFlow="false" transferMode="Buffered" transactionProtocol="OleTransactions" hostNameComparisonMode="StrongWildcard" listenBacklog="10" maxBufferPoolSize="524288" maxBufferSize="6553600" maxConnections="10" maxReceivedMessageSize="6553600">
    <readerQuotas maxDepth="32" maxStringContentLength="819200" maxArrayLength="163840" maxBytesPerRead="4096" maxNameTableCharCount="16384" />
    <reliableSession inactivityTimeout="00:01:00" ordered="true" enabled="true" />
    <security mode="None" />
  </binding>
 </netTcpBinding>
</bindings>

<behaviors>
 <serviceBehaviors>
  <behavior name="TabletSvcBehavior">
   <serviceDebug includeExceptionDetailInFaults="true" />
   <serviceThrottling maxConcurrentSessions="10" maxConcurrentInstances="10" maxConcurrentCalls="100" />
  </behavior>
 </serviceBehaviors>
</behaviors>

<diagnostics performanceCounters="Off" wmiProviderEnabled="False" >
  <messageLogging maxMessagesToLog="250" logEntireMessage="true" logMessagesAtServiceLevel="true" logMalformedMessages="true" logMessagesAtTransportLevel="true" />
</diagnostics>
</system.serviceModel>

Here is the stack trace of the exception:

10:20:18.3125 ClientChannel: Opening
10:20:48.8437 ClientChannel: Faulted
10:20:48.8593 Error: System.TimeoutException: The open operation did not complete within the allotted timeout of 00:00:00. The time allotted to this operation may have been a portion of a longer timeout. ---> System.TimeoutException: Open timed out after 00:00:00 while establishing a transport session to net.tcp://192.168.1.100:50000/TabletSvc/. The time allotted to this operation may have been a portion of a longer timeout. ---> System.TimeoutException: Connecting to via net.tcp://192.168.1.100:50000/TabletSvc/ timed out after 00:00:00. Connection attempts were made to 0 of 1 available addresses (). Check the RemoteAddress of your channel and verify that the DNS records for this endpoint correspond to valid IP Addresses. The time allotted to this operation may have been a portion of a longer timeout.
   at System.ServiceModel.Channels.SocketConnectionInitiator.CreateTimeoutException(Uri uri, TimeSpan timeout, IPAddress[] addresses, Int32 invalidAddressCount, SocketException innerException)
   at System.ServiceModel.Channels.SocketConnectionInitiator.Connect(Uri uri, TimeSpan timeout)
   at System.ServiceModel.Channels.BufferedConnectionInitiator.Connect(Uri uri, TimeSpan timeout)
   at System.ServiceModel.Channels.TracingConnectionInitiator.Connect(Uri uri, TimeSpan timeout)
   at System.ServiceModel.Channels.ConnectionPoolHelper.EstablishConnection(TimeSpan timeout)
   --- End of inner exception stack trace ---
   at System.ServiceModel.Channels.ConnectionPoolHelper.EstablishConnection(TimeSpan timeout)
   at System.ServiceModel.Channels.ClientFramingDuplexSessionChannel.OnOpen(TimeSpan timeout)
   --- End of inner exception stack trace ---

Server stack trace: 
   at System.ServiceModel.Channels.ClientFramingDuplexSessionChannel.OnOpen(TimeSpan timeout)
   at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout)
   at System.ServiceModel.Channels.ReliableChannelBinder`1.ChannelSynchronizer.SyncWaiter.TryGetChannel()
   at System.ServiceModel.Channels.ReliableChannelBinder`1.ChannelSynchronizer.SyncWaiter.TryWait(TChannel& channel)
   at System.ServiceModel.Channels.ReliableChannelBinder`1.ChannelSynchronizer.TryGetChannel(Boolean canGetChannel, Boolean canCauseFault, TimeSpan timeout, MaskingMode maskingMode, TChannel&am开发者_如何学Gop; channel)
   at System.ServiceModel.Channels.ReliableChannelBinder`1.Send(Message message, TimeSpan timeout, MaskingMode maskingMode)
   at System.ServiceModel.Channels.SendReceiveReliableRequestor.OnRequest(Message request, TimeSpan timeout, Boolean last)
   at System.ServiceModel.Channels.ReliableRequestor.Request(TimeSpan timeout)
   at System.ServiceModel.Channels.ClientReliableSession.Open(TimeSpan timeout)
   at System.ServiceModel.Channels.ClientReliableDuplexSessionChannel.OnOpen(TimeSpan timeout)
   at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout)
   at System.ServiceModel.Channels.ServiceChannel.OnOpen(TimeSpan timeout)
   at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout)
   at System.ServiceModel.Channels.ServiceChannel.CallOpenOnce.System.ServiceModel.Channels.ServiceChannel.ICallOnce.Call(ServiceChannel channel, TimeSpan timeout)
   at System.ServiceModel.Channels.ServiceChannel.CallOnceManager.CallOnce(TimeSpan timeout, CallOnceManager cascade)
   at System.ServiceModel.Channels.ServiceChannel.EnsureOpened(TimeSpan timeout)
   at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout)
   at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs)
   at System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation)
   at System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message)

Exception rethrown at [0]: 
   at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
   at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)

I had this issue too. I had resolved it with replacement of "Localhost" by "127.0.0.1".

NET application running on Windows XP SP2

Note: For Windows XP Professional, the maximum number of other computers that are permitted to simultaneously connect over the network is ten. This limit includes all transports and resource sharing protocols combined. For Windows XP Home Edition, the maximum number of other computers that are permitted to simultaneously connect over the network is five.

Microsoft KB

Also add this to your app/web.config

<system.net>
   <connectionManagement>
     <add address="*" maxconnection="5000" />
   </connectionManagement>
</system.net> 

Microsoft never meant for the network stack in XP to handle so many connections...