CommunicationException during a load test

Question

I'm working on a wcf application and I'm started to see an strange timeouts behavior on it. I created a foo application with the same configuration as the real one in order to determine if the problem is wcf related or not.

The client application code is this:

public class Clients
{
    public static void Main(string[] args)
    {
        var random = new Random();
        var run = true;
        var threads = 100;

        for (int i = 0; i < threads; i++)
        {
            int delay = random.Next(1000, 1500);

            var t = new Thread(() => {
                var id = Guid.NewGuid().ToString("N").Substring(0, 10);
                var client = new Client(@"client");

                while (run)
                {
                    Console.WriteLine(@"Sending thread id " + id);
                    client.Operation(@"Thread " + id);
                    Thread.Sleep(delay);
                }
            });
            t.Start();
        }
    }
}

The server application code only logs the data sent to the console:

[ServiceBehavior(ConcurrencyMode = ConcurrencyMode.Multiple,
    InstanceContextMode = InstanceContextMode.Single,
    IncludeExceptionDetailInFaults = true,
    UseSynchronizationContext = false,
    ValidateMustUnderstand = false)]
public class Service : IService
{
    public void Operation(string data)
    {
        Console.WriteLine(@"Data received: {0}", data);
    }
}

And this is the app.config file:

<?xml version="1.0"?>
<configuration>
<system.serviceModel>
<services>
  <service name="Test.Service" behaviorConfiguration="throttle">
    <endpoint name="service" 
              address="net.tcp://localhost/service" 
              binding="netTcpBinding" 
              bindingConfiguration="NetTcpBinding" 
              contract="Test.IService"/>
  </service>
</services>
<client>
  <endpoint name="client"
        address="net.tcp://localhost/service"
        binding="netTcpBinding" 
        bindingConfiguration="NetTcpBinding" 
        contract="Test.IService"/>
</client>
<bindings>
  <netTcpBinding>
    <binding name="NetTcpBinding"
             portSharingEnabled="true" 
             closeTimeout="00:01:00" 
             openTimeout="00:00:30" 
             receiveTimeout="00:00:10"
             sendTimeout="00:00:10"
             transactionFlow="false" 
             transferMode="Streamed" 
             transactionProtocol="OleTransactions"
             hostNameComparisonMode="StrongWildcard" 
             maxBufferPoolSize="6553600"
             maxBufferSize="6553600"
             maxConnections="500"
             maxReceivedMessageSize="6553600">
      <readerQuotas maxDepth="128" 
                    maxStringContentLength="3276800" 
                    maxArrayLength="6553600" 
                    maxBytesPerRead="1638400"
                    maxNameTableCharCount="6553600"/>
      <security mode="None">
        <transport protectionLevel="None"/>
      </security>
    </binding>
  </netTcpBinding>
</bindings>
<behaviors>
  <serviceBehaviors>
    <behavior name="throttle">
      <serviceThrottling maxConcurrentCalls="1000" 
                         maxConcurrentInstances="10"
                         maxConcurrentSessions="500"/>
    </behavior>
  </serviceBehaviors>
</behaviors>
</system.serviceModel>

If a run both applications and the number of threads of the Client application is 100 everything is ok. But if I change the number of threads to 300 I get the following exception:

System.ServiceModel.CommunicationException: The socket connection was aborted. 
This could be caused by an error processing your message or a receive timeout 
being exceeded by the remote host, or an underlying network resource issue. 
Local socket timeout was '00:00:10'.---> System.Net.Sockets.SocketException: 
An existing connection was forcibly closed by the remote host at
System.ServiceModel.Channels.SocketConnection.ReadCore(Byte[] buffer, Int32 
offset, Int32 size, TimeSpan timeout, Boolean closing)

I'm using port sharing on a quad-core machine and the service is self hosted.

This is the same problem I have in the real application but with a higher timeout (2 minutes and a half). I can't believe that 300 is the maximum number of connections a service with InstanceContextMode.Single can handle. I read about problems with the default ChannelInitializationTimeout value (which is set to five) but I don't think that's the problem (in another test I started creating and opening a single client for all the threads, and waited for 6 seconds to start all the threads, the result was the same exception after 10 seconds). Perhaps I'm configuring something in a wrong way.

If someone has a clue or ideas they will be helpful. Thanks in advance.

Update

I changed the binding from netTcp to basicHttpBinding and now everything works fine (no CommunicationExceptions thrown). Also I started to get messages in the service faster than before, does anyone know why I'm getting this improvement with basicHttpBinding?