TCP Chimney Offloading won't enable

i'm trying enable tcp offloading on 2008r2 box.  everything try doesn't seem work.  i checking weather offloading using following command netstat -t, listed in following article.  http://support.microsoft.com/kb/951037

this have tried:

- netsh int tcp set global chimney=enabled  (restarted)

- added following registry entry " hkey_local_machine\system\currentcontrolset\services\tcpip\parameters"     enabletcpchimney set 1   (restarted)

- enabled tcp offload features within nic configuration page  (restarted)

 

according article, should see:

this keep getting after applying changes should enable it.

 

here status of tcp parameters

i see have tcp/udp , ip checksum offload enabled not related tcp chimney (connection offload or full tcp offload). additionally see have enabled large send offload , delegates segmentation of large tcp packets process nic. of nics have them enabled default.

if read description above on intel nic when highlight ipv4 checksum says offload.

however, nics support tcp chimney (connection offload or full tcp offload). manufactures refer tcp offload engine or toe.
tcp offload engine
http://en.wikipedia.org/wiki/tcp_offload_engine

i’m summarizing here what ndis 6.0 supports task offload:

• checksum tasks - tcp/ip transport can offload calculation , validation of ip , tcp checksums.
• large send offload - the tcp/ip transport can offload segmentation of large tcp packets.
• connection offload - enable configuration of connection offload services such tcp chimney offload.
  

there are points differentiate here tcp/ip has multiple fields each one offers different functions , couple them can partially offloaded. first 2 offload part of functions (checksum , large segments) , third offload connection nic.

reference:
ndis 6.0 support task offload
http://msdn.microsoft.com/en-us/library/windows/hardware/ff564713(v=vs.85).aspx

so, @ point recommend double check manufacture if nic model have supports tcp chimney/toe or full tcp offload.

i hope gives clarification.

-daniel mauser

Windows Server  >  Platform Networking