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New Member

does etherchannel require lacp or pagp

I need to configure an etherchannel and was wondering if either lacp or pagp have to be configured in conjunction with it?

Thanks.

7 REPLIES
VIP Purple

Re: does etherchannel require lacp or pagp

Hello,

you do not need PAgP (Cisco-proprietary) or LACP (IEEE 802.3ad standard), when you set your channel to:

channel-group 1 mode on

PAgP and LACP are disabled.

Here are the available channel modes:

On

--> PAgP and LACP disabled (no negotiation)

Desirable

--> Actively negotiate PAgP

Auto

--> Passively listen for PAgP

Active

--> Actively negotiate LACP

Passive

--> Passively listen for LACP

The following combinations for both sides will result in successfully establishing the channel:

On -- On

Desirable -- Desirable

Desirable -- Auto

Active -- Active

Active -- Passive

HTH,

GP

Purple

Re: does etherchannel require lacp or pagp

If you have cisco on both sides just run pagp with both sides set to desirable. If you have mixed gear then you need to runn lacp . The general cisco recomendation is to set both sides as desirable.

New Member

Re: does etherchannel require lacp or pagp

Thanks for everybody's responses. What is the upside of using or downside of not using pagp/lacp.

Thanks again

VIP Purple

Re: does etherchannel require lacp or pagp

Hello,

the main difference is that PAgP is Cisco-proprietary, while LACP is IEEE defined (802.3ad), AFAIK, the protocols are quite similiar, with a few exceptions, e.g. LACP does not support half-duplex links.

HTH,

GP

New Member

Re: does etherchannel require lacp or pagp

Thanks. I guess what I am really trying to understand is the rational of creating an etherchannel without either PAgP or LACP. Would would be the downside? Thanks.

VIP Purple

Re: does etherchannel require lacp or pagp

Hello,

I guess it can be compared to duplex and speed autonegotiatin in Ethernet environments. Setting speed and duplex to a fixed value on both sides is preferable when you are sure that either side will never be used for anything else than the device it is connected to. So, I would always disable negotiation if possible...

HTH,

GP

Super Bronze

Re: does etherchannel require lacp or pagp

Hi

Just thought I'd throw in another bit of info... if you're using 3750s and want to do FEC to two switches in a stack you need to manually configure it using the 'channel-group 1 mode on' command on the ports as opposed to using PAgP or LACP.

Which is handy sometimes.

Aaron

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!
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