Microsoft KB Archive/816496

= TCP Congestion Window Does Not Return to Optimal Length in Bidirectional Communication Streams =

Article ID: 816496

Article Last Modified on 7/24/2007

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APPLIES TO


 * Microsoft Windows Server 2003, Enterprise x64 Edition
 * Microsoft Windows Server 2003, Enterprise Edition (32-bit x86)
 * Microsoft Windows Server 2003, Standard Edition (32-bit x86)
 * Microsoft Windows XP Home Edition
 * Microsoft Windows XP Professional
 * Microsoft Windows 2000 Advanced Server
 * Microsoft Windows 2000 Professional Edition
 * Microsoft Windows 2000 Server

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SYMPTOMS
In communication streams where there is bidirectional traffic, the TCP congestion window may not return to an optimal length for the network conditions.



CAUSE
TCP/IP applications that send high volumes of data and receive small replies may affect the NT4 stack (specifically the Tcpip.sys file) in such a way that throughput is continually diminished on a particular socket connection.



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 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

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 tool in Control Panel. Date         Time  Version         Size   File name

14-Jan-2004  09:58 5.2.3790.118 334,336   Tcpip.sys

Hotfix information
A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may 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 immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

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

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.

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 tool in Control Panel.   Date         Time   Version        Size     File name -  23-Aug-2003  11:27  5.1.2600.1271  339,968  Tcpip.sys

Hotfix information
A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Windows 2000 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

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

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.

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 tool in Control Panel.   Date         Time   Version        Size     File name 18-Jul-2003 17:00  5.0.2195.6787  118,992  Afd.sys 28-Jul-2003 20:27  5.0.2195.6602  108,816  Msafd.dll 18-Jul-2003 17:33  5.0.2195.6787  314,928  Tcpip.sys 15-Jan-2003 17:56  5.0.2195.6655   16,240  Tdi.sys 28-Jul-2003 20:27  5.0.2195.6601   17,680  Wshtcpip.dll



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



MORE INFORMATION
If response frames come back out of order, load-balanced links and frame relay links will aggravate this problem. The round-trip time counter incorrectly interprets frames that are out of order as congestion and triggers congestion avoidance. On high-latency networks, the send window drops very low and may cause substantial delays. For additional information about how to obtain a hotfix for Windows 2000 Datacenter Server, click the article number below to view the article in the Microsoft Knowledge Base:

265173 The Datacenter Program and Windows 2000 Datacenter Server Product

Keywords: kbhotfixserver kbqfe kbqfe kbwin2000presp4fix kbfix kbbug KB816496

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