6500 etherchannel issue?

Hi I have a 6500 (redundant) with 10 3750 singles and 4 stacks of two all configured with 2gb etherchannels across two line cards. If I disable card 4, thus bringing every channel down to one gig it all works peachy. When I enable the 2nd card it all goes horribly wrong.

On a bare bones config I have only two vlans created, the vtp mode as transparent, etherchannel mode on, trunking as dot1q on. I leave it like this for a few minutes and my end to end starts to crumble with no emor messages and all port lights blazing away, I disconnect or shut down one of my line cards and it all comes back

It must be the etherchannel!

Spanning-tree is left at default. My stacks are all happy and priorotised.

Anybody any good ideas? :o)

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On 16.02.2006 20:00 traust wrote

Ever tried PaGP or LACP to form the channels?


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Arnold Nipper

Clearly this looks like a loop.

As I recall the current recommendation is to have the channels on desirable/desirable (one end/other end). I cannot recall the details however I think that it is to do with avoiding loops.

I am not sure what the recommendation is regarding trunking. It seems less likely to go horribly wrong but I now quite fancy a similar configuration there too.

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trunk mode on - encapsulation negotiate off no comment on PAgP.

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