Description of a hotfix that adds Compound TCP (CTCP) support to computers that are running Windows Server 2003 or a 64-bit version of Windows XP

A hotfix is available to add Compound TCP (CTCP) support to computers that are running Windows Server 2003 or a 64-bit version of Windows XP. CTCP aggressively adjusts the congestion window of the sender to optimize TCP for connections with large bandwidth-delay products. These products include Video on Demand for Windows Server 2003 and for 64-bit versions of Windows XP.

Note CTCP support was introduced in Windows Vista and in Windows Server 2008.

Windows Server 2003 hotfix information

A supported hotfix is 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 software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if 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. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

To apply this hotfix, you must have Windows Server 2003 Service Pack 1 or Windows Server 2003 Service Pack 2 installed.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

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 Server 2003 Service Pack 1, x86-based versions

Windows Server 2003 Service Pack 2, x86-based versions

Windows Server 2003 Service Pack 1, Itanium-based versions

Windows Server 2003 Service Pack 2, Itanium-based versions

Windows Server 2003, x64 based versions

Windows Server 2003 Service Pack 2, x64 based versions

Windows XP hotfix information

A supported hotfix is 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 software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if 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. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

To apply this hotfix, you must have a 64-bit version of Windows XP installed.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

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, x64-based versions

Windows XP Service Pack 2, x64-based versions

Note When you apply this hotfix, the following registry subkey is created: The properties of this subkey are as follows: When the value is set to 1, CTCP support is enabled. When the value is set to 0, CTCP support is disabled.

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

Compound TCP (CTCP) aggressively increases the send window for connections with large receive window sizes and bandwidth-delay products (BDPs). CTCP tries to maximize throughput on these types of connections by monitoring delay variations and losses. Additionally, CTCP makes sure that its behavior does not adversely affect other TCP connections.

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