etherchannel problems between 6509 and 3750 stack

Answered Question
Dec 21st, 2008

6509 is running IOS ver 72033.advipservcesk9_wan_mz.122-33.SXH2a

3750 stack consists of one 3750g-24ts and one 3750-24p running ipbasek9-122.46(SE).

When each end configured for "channel-group n mode on" the 3750 ports go into err-disable. With each end configured for "channel-group n mode desirable" 3750 will fail because PAgP does not work across stack, etherchannel ports need to be on same switch.

Has anyone else seen this problem and what action was taken to overcome this problem?

I have this problem too.
0 votes
Correct Answer by MUHAMMAD SHAHEEN about 7 years 10 months ago

Hi Rob,

Follow this link to setup the Ether-Channels

Hope This helps


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Overall Rating: 2 (2 ratings)
passioncas Sun, 12/21/2008 - 22:06

Configure the etherchannel with the commands ( channel-group n mode )instaed of desirable.Pleaseet me know how its working once it is done.

archari Mon, 12/22/2008 - 07:25

When it does happen can you collect o/p of

show errdisable recovery

show errdisable flap-values

glen.grant Mon, 12/22/2008 - 09:04

I also recommend using LACP to set up the etherchannels. "channel-group 1 mode active" on both ends . There should be no problems once you do this , we have this same setup going all over.

robj Mon, 12/22/2008 - 21:16

Setting the "channel-group n mode on" command works providing you set the channel-group on the 3750 stack first, then the 6500 core node. Otherwise for some reason the switch ports go into "err-disable" and the ports have to be shut/no shut and the port-channel definition deleted and then re-instated.


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