Disabling the TCP Chimney

With the release of the Scalable Networking Pack that is included with Windows 2003 SP2, we in the ProjectWise Community have been seeing some connectivity issues once the new networking features are enabled. These new features are enabled by default and are only used if your network card driver supports them. Some of the new architectural additions that were introduced with the Scalable Networking Pack are TCP Chimney Offload, Receive-side Scaling (RSS) and NetDMA.

What this is does essentially is to offload TCP/IP packet processing to the network card, thus freeing up valuable CPU cycles for your applications. The throughput increases that you can get from having these enabled are quite significant.

Since we are still seeing some users that are not immediately successful in disabling the TCP chimney at our (preemptive) request. The very talented guys in TSG PRT had decided to create a registry file to disable 3 of the 9 global registry settings used by "The Microsoft Windows Server 2003 Scalable Networking Pack release".

Below is the registry key info. Copy and paste into a text file named TcpChimneyDisable.reg

Windows Registry Editor Version 5.00