channel-protocol {pagp|lacp}

Answered Question
May 15th, 2009

I've been using command

channel-group {#} mode {on|desirable|...etc}

for port-channel negotiation. However, I saw this command

channel-protocol {pagp|lacp}

on Cisco doco but I'm not really sure the implication compared with channel-group command. Is there something superfluous or there is more about it?

Regards,

David Sudjiman

I have this problem too.
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Correct Answer by Edison Ortiz about 7 years 8 months ago

If you enter "channel-group mode passive" under the interface, entering "channel-protocol pagp" won't change the etherchannel mode.

In the same token, on this scenario neither LACP nor PAgP will work as the channel-protocol and channel-group must match if you decide to use channel-protocol command.

__

Edison.

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iyde Sat, 05/16/2009 - 03:06

Hi.

Channel-protocol command is for setting whether you want to sue Cisco's original, but proprietary, PAgP protocol for etherchanneling or you will use the IEEE standard LACP protocol.

Depending on protocol you keywords for the mode command will differ (LACP has active and passive where PAgP has desirable and auto).

HTH

glen.grant Sat, 05/16/2009 - 04:30

I have never really understood why that command is there , if you use channel-group mode desirable it is pagp and if you use channel-group mode active it is lacp so why is the extra command even there as they work without it ?

Edison Ortiz Sat, 05/16/2009 - 12:05

David,

Use the channel-protocol command only to restrict a channel to LACP or PAgP. If you set the protocol by using the channel-protocol command, the setting is not overridden by the channel-group interface configuration command.

You must use the channel-group interface configuration command to configure the EtherChannel parameters. The channel-group command also can set the mode for the EtherChannel.

You cannot enable both the PAgP and LACP modes on an EtherChannel group.

PAgP and LACP are not compatible; both ends of a channel must use the same protocol.

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_46_se/command/reference/cli1.html#wp2748472

HTH,

__

Edison.

davidsudjiman Tue, 05/19/2009 - 04:50

Sorry, I still don't understand this

"If you set the protocol by using the channel-protocol command, the setting is not overridden by the channel-group interface configuration command."

Could you please elaborate?

Correct Answer
Edison Ortiz Tue, 05/19/2009 - 05:02

If you enter "channel-group mode passive" under the interface, entering "channel-protocol pagp" won't change the etherchannel mode.

In the same token, on this scenario neither LACP nor PAgP will work as the channel-protocol and channel-group must match if you decide to use channel-protocol command.

__

Edison.

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