Microsoft KB Archive/931618

= The two sides of an audio call may not hear one another on a Windows XP-based computer that has Communicator installed =

Article ID: 931618

Article Last Modified on 11/30/2007

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APPLIES TO


 * Microsoft Windows XP Home Edition
 * Microsoft Windows XP Professional

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SYMPTOMS
You use a Windows XP-based computer that has Microsoft Office Communicator installed. When you make an audio call to another computer that has Communicator installed, the two sides of the call may not hear one another. In some cases, only one side of the call may hear the audio.

If you capture the network traffic when this problem occurs, you find that the User Datagram Protocol (UDP) packets do not have the Encapsulating Security Payload (ESP) header.

Note Any application that provides peer-to-peer audio and video communication may be affected by this problem.



CAUSE
Under certain circumstances, the ESP header is not included in the peer-to-peer UDP traffic between two client computers. Therefore, the packets may be dropped on the recipient computer without notification. Additionally, the Winsock client may not send the packet to the recipient computer.



Hotfix information
A supported hotfix is now available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Windows XP service pack that contains this hotfix.

To resolve this problem, submit a request to Microsoft Online Customer Services to obtain the hotfix. To submit an online request to obtain the hotfix, visit the following Microsoft Web site:

http://go.microsoft.com/?linkid=6294451

Note If additional issues occur or any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. To create a separate service request, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Prerequisites
Windows XP Service Pack 2 (SP2) must be installed before you apply this hotfix.

Restart requirement
You must restart the computer after you apply this hotfix.

Hotfix replacement information
This hotfix does not replace a previously released hotfix.

Registry information
To use one of the hotfixes in this package, you do not have to make any changes to the registry.

File information
The English 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.

Windows XP, x86-based versions


STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section.



MORE INFORMATION
For more information about how to capture network traffic, click the following article number to view the article in the Microsoft Knowledge Base:

148942 How to capture network traffic with Network Monitor

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates

Keywords: kbexpertiseadvanced kbfix kbqfe kbhotfixserver KB931618

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