Cisco Systems DSC9148D8G48PK9 manual PortChannel Protocols, Forcing an Interface Addition

Chapter 6 Configuring PortChannels

Information About PortChannels

Suspended and Isolated States

If the operational parameters are incompatible, the compatibility check fails and the interface is placed in a suspended or isolated state based on the configured mode:

•An interface enters the suspended state if the interface is configured in the ON mode.

•An interface enters the isolated state if the interface is configured in the ACTIVE mode.

Forcing an Interface Addition

You can force the port configuration to be overwritten by the PortChannel. In this case, the interface is added to a PortChannel.

•If you use the default ON mode to avoid inconsistent states across switches and to maintain consistency across switches, then the ports shut down. You must explicitly enable those ports again.

•If you use the ACTIVE mode, then the PortChannel ports automatically recover from the addition.

Note When PortChannels are created from within an interface, the force option cannot be used.

After the members are forcefully added, regardless of the mode (ACTIVE and ON) used, the ports at either end are gracefully brought down, indicating that no frames are lost when the interface is going down (see the “Graceful Shutdown” section on page 2-9).

Interface Deletion from a PortChannel

When a physical interface is deleted from the PortChannel, the channel membership is automatically updated. If the deleted interface is the last operational interface, then the PortChannel status is changed to a down state. Deleting an interface from a PortChannel decreases the channel size and bandwidth of the PortChannel.

•If you use the default ON mode to avoid inconsistent states across switches and to maintain consistency across switches, then the ports shut down. You must explicitly enable those ports again.

•If you use the ACTIVE mode, then the PortChannel ports automatically recover from the deletion.

After the members are deleted, regardless of the mode (ACTIVE and ON) used, the ports at either end are gracefully brought down, indicating that no frames are lost when the interface is going down (see the “Generation 1 PortChannel Limitations” section on page 6-14and “Graceful Shutdown” section on page 2-9).

PortChannel Protocols

In earlier Cisco SAN-OS releases, PortChannels required additional administrative tasks to support synchronization. The Cisco NX-OS software provides robust error detection and synchronization capabilities. You can manually configure channel groups or they can be automatically created. In both cases, the channel groups have the same capability and configurational parameters. Any change in configuration applied to the associated PortChannel interface is propagated to all members of the channel group.

A protocol to exchange PortChannel configurations is available in all Cisco MDS switches. This addition simplifies PortChannel management with incompatible ISLs. An additional autocreation mode enables ISLs with compatible parameters to automatically form channel groups without manual intervention.

	Cisco MDS 9000 Family NX-OS Interfaces Configuration Guide
OL-29284-01, Release 6.x		6-9