Only use 'speed nonnegotiate' command on active interfaces - IBM Switch Modules

Resolving The Problem

Source

RETAIN Tip:H194936

Symptom

Using the 'speed nonegotiate' command on non-active interfaces can produce unexpected link results, such as:

• A non-active interface is displayed as up and connected.
• A non-active interface is displayed as flapping (goes up and down unexpectedly).

Affected configurations

The system is configured with one or more of the following IBM Options:

• Cisco Gigabit Ethernet Switch Module for BladeCenter, Option part number 32R1892
• Cisco Systems Fiber Intelligent Gigabit Ethernet Switch Module for BladeCenter, Option part number 32R1888

This tip is not hardware specific.

This tip is not software specific.

Workaround

The default setting in the Cisco Internetwork Operating System (IOS) is no 'speed nonegotiate'. Do not use the command on non-active interfaces.

Additional Information

For Gigabit Ethernet interfaces, the default is no speed nonegotiate, which sets the speed to 1000 megabits per second (Mbps) and enables link negotiation for flow-control parameters and remote fault information.

The 'speed nonegotiate' command disables link negotiation. Some blades require 'speed nonegotiate' to be set for establishing link to the switch. When 'speed nonegotiate' is configured, the port will bring up the link whenever it detects signaling bits coming into it. There are numerous reasons that signaling bit can cause the switch to erroneously detect link up and down.

It is recommended not to use the 'speed nonegotiate' command unless necessary to bring up the blade link.