3COM switch has became my root bridge

[20deoctubre]

Hi all...
I would like some help with an issue I'm facing with a fiber optic ring made with 7 6250's.
I have attached the network topology. As it's seen in my attachment, my ring is connected to the Main SITE to a 3COM switch.
I have typed the "show spantree 1" command and it showed me that my root bridge (designated bridge) is the 3COM switch.
I'm running the default configuration (1x1 RSTP) on all my Omniswitches.

This made me rethink about if I should leave the 3COM switch within my STP topology or Should I deactivate the STP on the port connected to my Omniswitch? What do you think?

I just connected the network through my ring, and as far as I know it haven't had any connectiviy problem, but I would like to be sure why that switch has became my root bridge and if I should deactivate STP on the port connected to my Omniswitch.

I have forgotten to say that all the links between switches (including the 3COM) are just 1 link, so there isn't any loop between the Omniswitches and the 3COM, that's why I don't understand why this switch (3com) is also participating in the STP topology

Well, thanks in advance and thank you for your time
Regards

[one6f]

... but I would like to be sure why that switch has became my root bridge and if I should deactivate STP on the port connected to my Omniswitch.

Your 3Com switch has a Bridge ID (Priority+MAC) that is lower than all the other Alcatel switches, hence the other switches automatically select the 3Com as the root switch. You can set the root bridge priority to 0 on your Alcatel in an effort to secure the root bridge position, then you don't need to disable STP on 3Com port.

Code: Select all

bridge 1x1 1 priority 0

From your drawing you don't really needed STP on 3Com and STP can be disabled on the switch. But, just in case, I would prefer the first solution.

[20deoctubre]

Thank you very much for your answer

[tomslack34]

I was having a similar issue. So glad I came across this. Thanks for the info.
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3com switch