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Newbie - spanning tree problem

Hi all, i have some problems with my Cisco switches as follows.

The company i work for has a Cisco 2900 switch for the internet communication and it runs by another department, in the house there i work i have 5 other switches (Cisco) i also have some 3Com. My ciscos is connected to a 3Com and the 3com is connected to the 2900. The tech who administrate the 2900 is now using BPDU guard, and that gave me some problems with my switches since his one is disabling the port im using in his switch and he said to me that it was a spanning tree problem.

Now i wonder if there is a simple solution to this problem ? can i disable the spanning tree feature or something like that in my switches, i use them like hubs so i dont have to use all the features in them.

My switches are 2948G, 3500 and 2950.

Tnx all.

// Tomas

New Member

Re: Newbie - spanning tree problem

Tomas, you could disable spanning tree on your 3COM as portfast bpdu-guard enabled ports will disable upon receiving a BPDU. Make sure that that you only have a single interlink\uplink between your switches as you will be wide open to SPT Loops otherwise.

If possible why not disable portfast on the 2900 and let spanning tree do its thing assuming your environment is stable.


Re: Newbie - spanning tree problem

Hi and tnx

Ok, but i was assuming that the ciscos was my problem since it only appears when i connect them to the net, my 3com switches does not make the same problem for me.

If you mean that he should not use the BPDU guard, then its a problem because thats what he wants to do and i have only one uplink but he does not trust my network since this is a secondary upper school with aprox 1200 students.

// Tomas

New Member

Re: Newbie - spanning tree problem

Tomas by turning off spanning-tree on your equipment will esure no BPDU's will be recieved on the C2900 therefore portfast bpdu-guard will not disable the port. Disable SPT with caution though. Make sure there is no possibility of SPT loops in your design.

Cheers, John.

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