Multiple issues that are fixed in .NET Framework 4.0-based WCF services


Issue 1

When a Microsoft .NET Framework 4.0-based Windows Communication Foundation (WCF) service uses a NetTcpBinding binding, concurrent connections do not scale correctly.

  • This issue occurs only if the service uses the TransferMode.Streamed member in the TransferMode property. The issue does not occur if the service uses the TransferMode.Buffered member in the TransferMode property.
  • This issue occurs only if the service uses at least one of the following Net.TCP features:
    • Service endpoints that use the Net.TCP Port Sharing Service
    • Service endpoints that are hosted in IIS
    • Service endpoints that use transport security

Issue 2

Consider the following scenario:
  • You use a .NET Framework 4.0-based client application that uses the HTTP protocol over Secure Sockets Layer (SSL) to access a WCF service.
  • A System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelRequest object is invoked on the client application.
  • You close the connection to the WCF service. Or, the WCF service becomes unavailable.
  • A WebException exception is encountered.
In this scenario, the memory of the HttpChannelRequest object is not released. Therefore, a memory leak occurs, and the performance of the client application decreases.

Issue 3

You run a .NET Framework 4.0-based WCF service that uses the netTcpBinding binding. When a transient network error occurs, the service crashes because of a System.ServiceModel.CommunicationException exception. This exception may be caused by a time-out or by an underlying network resource issue.
Call stack information for issue 3
at System.ServiceModel.Channels.SecurityChannelListener`1.DuplexSessionReceiveMessageAndVerifySecurityAsyncResult.BeginTryReceiveItem(TimeSpan timeout, AsyncCallback callback, Object state)
at System.ServiceModel.Channels.SecurityChannelListener`1.ReceiveItemAndVerifySecurityAsyncResult`2.StartInnerReceive()
at System.ServiceModel.Channels.SecurityChannelListener`1.ReceiveItemAndVerifySecurityAsyncResult`2.Start()
at System.ServiceModel.Channels.SecurityChannelListener`1.DuplexSessionReceiveMessageAndVerifySecurityAsyncResult.ReceiveMessage(Object state)
at System.ServiceModel.Channels.IOThreadScheduler.CriticalHelper.WorkItem.Invoke2()
at System.Security.SecurityContext.Run(SecurityContext securityContext, ContextCallback callback, Object state)
at System.ServiceModel.Channels.IOThreadScheduler.CriticalHelper.WorkItem.Invoke()
at System.ServiceModel.Channels.IOThreadScheduler.CriticalHelper.ProcessCallbacks()
at System.ServiceModel.Channels.IOThreadScheduler.CriticalHelper.CompletionCallback(Object state)


Hotfix information

A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that this article describes. Apply it only to systems that are experiencing this specific problem.

To resolve this problem, contact Microsoft Customer Support Services to obtain the hotfix. For a complete list of Microsoft Customer Support Services telephone numbers and information about support costs, visit the following Microsoft website:Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.


To apply this hotfix, you must have the .NET Framework 4.0 installed.

Restart requirement

You do not have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfix.

File Information

The global version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.
For all supported x86-based versions of the .NET Framework 4
File nameFile versionFile sizeDateTimePlatform
For all supported x64-based versions of the .NET Framework 4
File nameFile versionFile sizeDateTimePlatform
For all supported IA-64-based versions of the .NET Framework 4
File nameFile versionFile sizeDateTimePlatform


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

Artikelnummer: 2629846 – Letzte Überarbeitung: 16.02.2012 – Revision: 1