Poor TCP/IP Performance with Small Sends

 Last reviewed: March 6, 1998
Article ID: Q179279
The information in this article applies to:
  • Microsoft Commercial Internet System version 1.0 - Content Replication System
  • Site Server version 2.0 - Content Replication System

SYMPTOMS

When you are doing multiple sends of less than the Maximum Transmission Unit (MTU), you may see poor performance. On an Ethernet network, the default MTU for TCP/IP is 1,460 bytes. TCP can coalesce the two small sends into one larger packet. This concept of collecting small sends into larger packets is called Nagling.

Content Replication Server (CRS) in Microsoft Commercial Internet System (MCIS) 1.0 and Site Server 2.0 has Nagling enabled by default. The registry key 

   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\CRS\DisableNagle :REG_SZ: Yes/No
does not function properly in MCIS 1.0 and Site Server 2.0 CRS.

STATUS

Microsoft has confirmed this to be a problem in Microsoft Commercial Internet Server version 1.0 and Site Server version 2.0. This problem has been corrected in the latest U.S. Service Pack for Site Server 2.0 Service Pack 1. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces): 

   S E R V P A C K

MORE INFORMATION

Nagling is off by default in Site Server 2.0 SP1. Nagling is a large performance hit and greatly increases the time it takes for a replication to complete.

For additional information on Nagling, please see the following article in the Microsoft Knowledge Base: 

   ARTICLE-ID: Q126716
   TITLE     : PRB: Poor TCP/IP Performance When Doing Small Sends
See also RFC 1122. 
Keywords          : kbother kbbug2.00 kbbug1.00
Version           : WINDOWS:1.0,2.0
Platform          : WINDOWS
Issue type        : kbbug
Solution Type     : kbfix

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Last reviewed: March 6, 1998
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