Forcing An Interface Addition; Interface Deletion From A Portchannel; Portchannel Protocols - Cisco MDS 9000 Series Configuration Manual

Forcing an Interface Addition

• 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
• 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, on page

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
• 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
1 PortChannel Limitations, on page 232

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.
The PortChannel protocol is enabled by default.
The PortChannel protocol expands the PortChannel functional model in Cisco MDS switches. It uses the
exchange peer parameters (EPP) services to communicate across peer ports in an ISL. Each switch uses the
information received from the peer ports along with its local configuration and operational values to decide
if it should be part of a PortChannel. The protocol ensures that a set of ports are eligible to be part of the same
PortChannel. They are only eligible to be part of the same PortChannel if all the ports have a compatible
partner.
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across switches, then the ports shut down. You must explicitly enable those ports again.
23) sections.
across switches, then the ports shut down. You must explicitly enable those ports again.
and Graceful Shutdown, on page 23
Configuring PortChannels
Generation
sections).