PortChannel Modes

You can configure each PortChannel with a channel group mode parameter to determine the PortChannel protocol behavior for all member ports in this channel group. The possible values for a channel group mode are as follows:

ON (default)—The member ports only operate as part of a PortChannel or remain inactive. In this mode, the PortChannel protocol is not initiated. However, if a PortChannel protocol frame is received from a peer port, the software indicates its nonnegotiable status. This mode is backward compatible with the existing implementation of PortChannels in releases prior to Release 2.0(1b), where the channel group mode is implicitly assumed to be ON. In Cisco MDS SAN-OS Releases 1.3 and earlier, the only available PortChannel mode was the ON mode. PortChannels configured in the ON mode require you to explicitly enable and disable the PortChannel member ports at either end if you add or remove ports from the PortChannel configuration. You must physically verify that the local and remote ports are connected to each other.

ACTIVE—The member ports initiate PortChannel protocol negotiation with the peer port(s) regardless of the channel group mode of the peer port. If the peer port, while configured in a channel group, does not support the PortChannel protocol, or responds with a nonnegotiable status, it will default to the ON mode behavior. The ACTIVE PortChannel mode allows automatic recovery without explicitly enabling and disabling the PortChannel member ports at either end.

Table 10-1 Channel Group Configuration Differences
ON Mode	ACTIVE Mode
No protocol is exchanged.	A PortChannel protocol negotiation is performed with the peer ports.
Moves interfaces to the suspended state if its operational values are incompatible with the PortChannel.	Moves interfaces to the isolated state if its operational values are incompatible with the PortChannel.
When you add or modify a PortChannel member port configuration, you must explicitly disable (shut) and enable (no shut) the PortChannel member ports at either end.	When you add or modify a PortChannel interface, the PortChannel automatically recovers.
Port initialization is not synchronized.	There is synchronized startup of all ports in a channel across peer switches.
All misconfigurations are not detected as no protocol is exchanged.	Consistently detect misconfigurations using a PortChannel protocol.
Transitions misconfigured ports to the suspended state. You must explicitly disable (shut) and enable (no shut) the member ports at either end.	Transitions misconfigured ports to the isolated state to correct the misconfiguration. Once you correct the misconfiguration, the protocol ensures automatic recovery.
This is the default mode.	You must explicitly configure this mode.