Etherchannel question

So there is PAGP and LACP as the two protocols, one proprietary, one a standard. So my question is, what does Channel group 1 mode on do? If there are two protocols available, and "on" simply turns on etherchannel, what does it use? I don't understand how it could work without some sort of protocol.

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Comments

TechGuru80

If I remember correctly...the "on" just says it is on but doesn't actually function without specifying the protocol.

Heero

Mode "on" tell the switch to put the ports into an etherchannel without negotiating with the other side. The presents the obvious problem of mis-matched configuration on each side. If one side is set to "on" and the other is set to "lacp active" or whatever, then the lacp active side will never negotiate the etherchannel because the other side won't respond, and now you have one side that see the links as one logical link, and the other side that sees it as several different links and you start to run into STP problems.

Best practice is to just use lacp mode active on each side. Use "on" for situations where you have some sort of compatibility problem and you need to bypass the LAG negotiation.

davenull

Heero already explained it very well. What helps to understand it is if you think of PAGP and LACP as Etherchannel negotiation protocol, not Etherchannel protocols themselves. You can set both sides to negotiate using PAGP or LACP, or enable Etherchannel without the negotiation protocols by setting them to on.

DoubleNNs

Believe just turning it on just creates a static link aggregation. (Static LAG)
LACP/PAGP just negotiates to dynamically bring up the port channel.