Connecting 3 switches to a fourth switch, each with its own crossover cable shuts down ports

Mar 29, 2007 2 Replies

This is probably a very basic question but I need to ask it anyway since there is no easy way to test it while everyone is on the network. I have (3) 3com switches, all are connected via a proprietary backplane cable called a matrix cable whis is sort of like a crossover cable. I added a fourth switch, a Cisco catalyst, and decided to plug each 3com into the Cisco switch using three crossover cables, one cable for each 3com, connected to the Cisco. Later I would connect the Cisco to a trunk. After plugging in the three xover cables I noticed only one port was active, and if I unplugged the active port, one of the other two ports became active. Is this spannig tree? was it doing this to prevent a loop? Will this config work once I remove the matrix/ backplane cable?



thanks NH



...

Yes.

Yes, because you made loops. The stack cable makes the 3 behave as one.

It works now.

But, yes it will still work when you unstack them as well.

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