Enabling Offloads

•IP and TCP Checksum Offload—reduced CPU utilization by allowing the NIC to perform the checksum calculation of TCP/IP and UDP/IP packets.

•802.1p Packet Priority Offload—reduces CPU utilization by allowing the NIC to perform the insertion of the 802.1Q tag header into the packet.

Enabling Offloads

Windows 2003 and Windows 2000 provide the capability to individually enable or disable each of the four offload features. (The default setting for these features is enabled.)

To enable or disable individual offload settings in Windows 2003 or Windows 2000:

1Right-click the My Network Places desktop icon and select Properties. The Network and Dial-up Connections screen appears.

2Right-click the Local Area Connection icon and select Properties. The Local Area Connection Properties screen appears.

3Click Configure.

The 3Com 10/100 Mbps Secure NIC screen appears.

4Click the Advanced tab.

5Select Enable Offloads in the Property list box.

6Select the appropriate value in the Value entry box (shown in the following table) for the desired offload state.

7Close all open windows.

The following table describes values for the offload functions:

Value

Offload Function Enables

 

 

All Offloads Disabled

No offloads

cksum

TCP Checksum

cksum-ipsec

TCP Checksum and IPSec

cksum-tcpseg

TCP Checksum and TCP Segmentation

cksum-tcpseg-ipsec

TCP Checksum and TCP Segmentation and IPSec

ipsec

IP Sec

tcpseg

TCP Segmentation

tcpseg-ipsec

TCP Segmentation and IPSec

802.1p

Packet Priority

802.1p-cksum

Packet Priority and TCP Checksum

802.1p-cksum-ipsec

Packet Priority and TCP Checksum and IPSec

802.1p-cksum-tcpseg

Packet Priority and TCP Checksum and TCP Segmentation

802.1p-cksum-tcpseg-ipsec

Packet Priority and TCP Checksum and TCP Segmentation and

 

IPSec

802.1p-ipsec

Packet Priority and IPSec

802.1p-tcpseg

Packet Priority and TCP Segmentation

802.1p-tcpseg-ipsec

Packet Priority and TCP Segmentation and IPSec

 

 

41