Microsoft KB Archive/236926

= Windows 95 and Windows 98 TCP/IP May Retransmit Packets Prematurely =

Article ID: 236926

Article Last Modified on 1/24/2007

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APPLIES TO


 * Microsoft Windows 98 Second Edition
 * Microsoft Windows 98 Standard Edition
 * Microsoft Windows 95
 * Microsoft Windows 95
 * Microsoft Windows 95
 * Microsoft Windows 95
 * Microsoft Windows 95

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This article was previously published under Q236926



SYMPTOMS
When you are transmitting data over high-delay networks (for example, satellite links), transfer throughput may be lower than expected and the number of packets that is retransmitted may be unnecessarily high.



CAUSE
This problem occurs because TCP uses a retransmit timer to retransmit packets that do not seem to have reached the receiver. To set this timer, TCP uses information about the historical round-trip time (RTT) for each connection, which it measures by observing the time between sending packets and receiving acknowledgments for them.

The Windows 95 and Windows 98 TCP/IP stack incorrectly computes the retransmit timer because of a math error. When you transmit packets over high-delay networks, this can result in unnecessary retransmissions and lower throughput.



Windows 98 and Windows 98 Second Edition
A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem.

To resolve this problem immediately, download the fix by clicking the download link later in this article or contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS

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.

The following file is available for download from the Microsoft Download Center:

Download 236926usa8.exe now

For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:

119591 How to Obtain Microsoft Support Files from Online Services

Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to prevent any unauthorized changes to the file. The English-language version of this fix should have the following file attributes or later:   Date        Time      Version     Size     File name 08/13/99   2:04pm    4.10.2223   60,281   Vtcp.386

Windows 95 and Windows 95 OSR 1, 2, 2.1, 2.5
A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem.

To resolve this problem immediately, download the fix by clicking the download link later in this article or contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS

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.

The following file is available for download from the Microsoft Download Center:

Download 236926usa5.exe now

For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:

119591 How to Obtain Microsoft Support Files from Online Services

Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to prevent any unauthorized changes to the file. The English-language version of this fix should have the following file attributes or later:   Date       Time       Version     Size     File name   Platform -  07/29/99   12:53pm    4.00.1658   60,245   Vtcp.386    Windows 95 + WinSock2



STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.



MORE INFORMATION
You can observe the TCP retransmission count by using the netstat -s command.

For additional information about this issue as it pertains to Microsoft Windows NT, click the article number below to view the article in the Microsoft Knowledge Base:

232512 TCP/IP may Retransmit Packets Prematurely

For additional information about Windows 95 hotfixes, click the article number below to view the article in the Microsoft Knowledge Base:

161020 Implementing Windows 95 Updates

For additional information about Windows 98 and Windows 98 Second Edition hotfixes, click the article number below to view the article in the Microsoft Knowledge Base:

206071 General Information on Windows 98 and SE Hotfixes

Keywords: kbdownload kbgraphxlinkcritical kbqfe kbnetwork kbprb kbhotfixserver KB236926

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