UDLD and Spanning tree

[Patrick McHenry]

I'm thinking about using UDLD on our fiber links. I know that it is important that UDLD detects a uni-irectional link before spanning-tree converges. We have default timers for our spanning-tree configuration, which from what I understand, will give UDLD, in it's default form. enough time to tell if there is a unidirectional link and shut the port. But, I am going though the switches in the environment and changing our switches to use rpvst from pvst. By me doing this aren't I changing the time it takes for spanning-tree to converge, therefor, negating the UDLD?

Thanks, Pat.

[Jon Marshall]

Patrick

Good question. Have a look at this thread where Francios Tallet (Cisco STP expert) answers that very point -

https://supportforums.cisco.com/message/620848#620848

Jon

[Patrick McHenry]

Please, correct me if I do not understand.

Form the link you provided, I gather that if a link is bi-directional, rstp will go about it's normal fast convergence and all is good as there is a bi-directional link. If there is a unidirectional link, rstp falls back to spanning-tree timers and in that case, UDLD will kick in and shut the port in aggressive mode.

Thank, Pat.