Scalable Networking Pack revisited for 2008
A customer of mine has been enquiring about the current situation of Scalable Networking Pack in relation to Windows 2008. Out of my research I have come up with the following information plus also some recommendations.
After Windows 2003 SP2 this setting was enabled by default. Many customers experienced some issues http://support.microsoft.com/kb/948496/jp. This was related to the fact that certain NIC cards especially Broadcom had compatibility issues with Network cards using Broadcom 5708 chipsets are known to have compatibility issues w/ TCP Chimney Offload feature.
http://blogs.msdn.com/sqlprogrammability/archive/2008/05/27/sql-server-intermittent-connectivity-issue.aspx & http://blogs.technet.com/networking/archive/2008/11/14/the-effect-of-tcp-chimney-offload-on-viewing-network-traffic.aspx and http://support.microsoft.com/kb/942861
It was therefore advisable to “Switch off” the SNP via this registry key.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
EnableTCPA REG_DWORD 0x0 ßOK
EnableRSS REG_DWORD 0x0 ßOK
EnableTCPChimney REG_DWORD 0x0 ßOK
0 = disabled
1 = enabled default
With the release of 2008 I have been asked by my customer whether this is an issue still.
Well the answer is that potentially it could be , however to mitigate the issue ensure that you have the LATEST NIC card drivers as part of your server build, and checkout their comptibility with TCP Chimney Offload feature
Windows 2008 specific reference to Scalable Networking Pack.
http://support.microsoft.com/kb/951037
