NDIS 6.0 supports full TCP offload or "chimney offload" which provides a direct connection (a "chimney") between applications and a TCP offload-capable NIC. This feature enables such a NIC to perform TCP processing for offloaded connections which reduces processor overhead and makes network communications more efficient. For details, see http://msdn.microsoft.com/en-us/library/aa503758.aspx.
How can you verify whether this feature is enabled on a Windows Server 2008 server that has a TCP Offload Engine (TOE) NIC installed? Use the Netsh command as follows:
C:\>netsh int tcp show global
Querying active state…
TCP Global Parameters
Receive-Side Scaling State : enabled
Chimney Offload State : enabled
Receive Window Auto-Tuning Level : normal
Add-On Congestion Control Provider : ctcp
ECN Capability : disabled
RFC 1323 Timestamps : disabled
If TCP Chimney Offload is disabled, you can enable it using this command:
netsh int tcp set global chimney=enabled
Note that you must reboot your server after running the above command.