3750 StackWise not working...need your help.

Unanswered Question
Jul 23rd, 2007

Been deploying 3750s for awhile and this is the first time I've ran into this issue. We have 8 3750s stacked, with a 3-meter cable from switch 8 to switch 1 for redundancy. The link between switch-5 and switch-6 is down. Cheched and replaced stack cable, still down. What else can I do?

I have this problem too.
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Edison Ortiz Mon, 07/23/2007 - 06:28

Stacking is hardware dependent, nothing to do in the switch software config.

Try connecting switch's 5 port to another switch, if you get a connection, try the same from switch's 6 port and try to determine which port is bad.

Once you do, request a switch replacement from Cisco.

Pavel Bykov Tue, 07/24/2007 - 00:49

What I remember, but can't find a description of it on Cisco Web, is that once you connect stackwise in physical a loop, one of the links goes into down state.

Stackwise is loop by itself, that's my logical reasoning for this behavior. The down link becomes redundant link in case of failure.

As I said - i couldn't find the description of that in Cisco documents.

You can check it out if you have 2x 3750 in lab environment and interconnect them with stack. In fact, I'm going to go to the storage room and get me a couple of c3750 to check this.

Pavel Bykov Tue, 07/24/2007 - 01:03

Just confirmed it - if I connect two sitches in a stackwise physical loop, one port goes down.

This seems to be natural functioning.

jamesross Wed, 07/25/2007 - 09:25

I lab two new 3750s, and got "OK" on all ports.

I don't think it's anything like spanning-tree. Looks to be more physical, a bad stack port on either switch-5 or switch-6. Going to try replacing switch 5, then switch-6 if necessary.


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