Microsoft KB Archive/278902

= NLB Cluster Does Not Converge When the MTU Size Is Less Than the Default Value =

PSS ID Number: 278902

Article Last Modified on 10/21/2003

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The information in this article applies to:


 * Microsoft Windows Server 2003, Enterprise Edition

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This article was previously published under Q278902



SYMPTOMS
If the Maximum Transfer Unit (MTU) of computers that are in a cluster is set to less than the default value, the heartbeat message that is sent by Network Load Balancing Server (NLBS) is not handled as expected and the cluster may not converge.



CAUSE
This behavior can occur because the heartbeat protocol does not account for the heartbeats to be fragmented, and no reassembly is performed by NLBS.



RESOLUTION
Ensure that the MTU of computers taking part in a cluster is set to the default value.



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



MORE INFORMATION
For additional information about the NLBS heartbeat message, click the article number below to view the article in the Microsoft Knowledge Base:

232711 How Cluster Integrity Is Monitored in WLBS

For additional information about TCP/IP MTU size, click the article number below to view the article in the Microsoft Knowledge Base:

140375 Default MTU Size for Different Network Topology ID

Keywords: kbprb KB278902

Technology: kbWinServ2003Ent kbWinServ2003EntSearch kbWinServ2003Search

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