Guest

Cisco Catalyst 3500 XL Series Switches

Field Notice: FN - 61087 - Performance Issue with Intel Pro/1000T NICs Connecting to Catalyst 3500XL/2900XL with WS-G5482 1000 Base-T Copper GBIC


March 29, 2001


 

NOTICE:

THIS FIELD NOTICE IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTY OF MERCHANTABILITY. YOUR USE OF THE INFORMATION ON THE FIELD NOTICE OR MATERIALS LINKED FROM THE FIELD NOTICE IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS FIELD NOTICE AT ANY TIME.

Products Affected

Product

Top Assembly

Printed Circuit Assembly

Comments

HW Rev.

Part Number

Rev.

Part Number

Rev.

WS-G5482

800-09411-02

-A0

28-4303-06

-A0

 

-B0

 

Problem Description

Customers may experience poor performance or data transfer receive errors on their switches or their NIC server when they connect the Intel Pro/1000 T Gigabit Copper NIC to Catalyst 3500XL/2900XL 1000Base T copper GBIC, WS-G5482.

Background

Some MAC devices have a bug that prevents them from receiving odd length frames under certain conditions. This happens when the local PHY has the GMII interface and the link partner is using a TBI or SERDES interface (this is the case with the WS-G5482). These interfaces follow the IEEE 802.3 spec and stuff an extra byte when the frame is odd byte length (TR becomes TRR at the end of packet, IEEE 802.3, Clause 36.2.4.15). Some MAC devices are not designed to handle this case and they don't receive such odd byte length frames.

The interoperability issue arises when a module with a TBI interface transmits an odd byte packet to a receiver with a GMII interface.

This is because the WS-G5482 1000Base T GBIC forces even length packets with Carrier Extension. They do this by adding 1 byte of padding to the end of odd length packets. This extra data in the packet causes the hardware CRC check to fail on the Intel Pro 1000 T NIC.

Problem Symptoms

When an Intel Pro/1000 T NIC is connected to a Catalyst 2900XL/2900XL switch with a WS-G5482 1000Base T GBIC, a customer may see poor performance and excessive numbers of dropped packets. The interoperability issue arises when a module with a TBI interface transmits an odd byte packet to a receiver with a GMII interface.

This is because the WS-G5482 1000Base T GBIC forces even length packets with Carrier Extension. They do this by adding 1 byte of padding to the end of odd length packets. This extra data in the packet causes the hardware CRC check to fail on the Intel Pro 1000 T NIC.

To verify this issue, ping an even sized packet and ping an odd sized packet:

Ping an even size packet
Ping (ip address) -1 72

Ping an odd size packet
Ping (ip address) -1 73

Where the problem exists, the even size packet ping succeeds and the odd size packet pin fails.

The WS-G5482 1000Base T GBIC, while generating even length packets, can receive odd and even length packets without error.

Workaround/Solution

Intel has implemented an automated TBI workaround in their latest driver for the PRO/1000 T family of Server Adapters Gigabit software release 2.2.5. The Pro/1000 T family of Server Adapters Gigabit software release 2.2.5 (automated TBI workaround) has been posted to Intel Support leavingcisco.com.

Driver versions

  • NT4 & Windows 2000 (vers.2.84), (certified)

  • Novell (ver. 2.71)

  • UnixWare* 7.x/ddi8 (ver. 2.7.5 ) (UnixWare with ddi7 does not include workaround and so the gmii.htm page still reflects the workaround for that driver.)

For the Intel Pro/1000 T family of Server Adapters Gigabit software release 2.2.5, check Intel PRO/1000 T Server Adapter leavingcisco.com

For more information on Intel Pro/1000 T family of Server Adapters, check Intel PRO/1000 Family of Gigabit Server Adapters leavingcisco.com

Cisco has verified interoperability with the Intel Pro/1000 T Server Adapter with the new software release 2.2.5. Cisco and Intel are working to insure interoperability between future revisions of 1000BASE-T adapters and switch 1000BASE-T GBIC.

For More Information

If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) by one of the following methods:

Receive Email Notification For New Field Notices

Product Alert Tool - Set up a profile to receive email updates about reliability, safety, network security, and end-of-sale issues for the Cisco products you specify.