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Cisco Employee

3750 problem with gigastack

Good morning,

I have a stack of 4 3750. The models are:

WS-C3750G-12S-Standard Image x 2

WS-C3750-48TS-Standard Image x 1

WS-C3750-48TS-Enanced Image x 1

All of them are running IOS C3750-I9-M. When I connect them in a redundant configuration with other switching environment the Rapid spanning tree is not behaving properly. The redundant interfaces are changing state between forwarding and blocking. My suspect is that the stacking technology is not working properly (all the switches are stacked at the back with Cisco Stackwise technology). The spanning tree is not stable and could be for the different models in the gigastack. Did you get ever the same problem? Is there any raccomandation to not stack together different models? Any problem with the different IOS featuse set (enhanced again standard)?

Any CCO link for this?

Really thanks for your help.


Cisco Employee

Re: 3750 problem with gigastack

You only mentioned you are running EMI. What version of IOS are you running? Check out the following bug


Re: 3750 problem with gigastack

I would read thru the stacking pages and see if you can spot anything . Also the recomendation would to make sure the 3750 running the enhanced version should be the stackmaster if it is not already .