CRS: Poor TCP/IP Performance with Small Sends

• Microsoft Commercial Internet System version 1.0
• Microsoft Content Replication System
• Microsoft Site Server version 2.0

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

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

Additional query words:

Keywords          : kbother kbbug1.00 kbbug2.00 
Version           : WINNT: 1.0,2.0
Platform          : winnt 
Issue type        : kbbug 

Last Reviewed: July 16, 1999