I'd be interested in seeing an excerpt your log file for this.We recently had the same problem on a pair of our 7200's where the state changes would occur within ms of each other ruling out missed hello's.
Correct. From an admin point of view, it's a good idea to manually set your primary and secondary root rather than leaving it to the STP algorithm.Sorry I can't help you on the feature set of the C3500XL but that info should be easy to find here at ...
Which STP are you running ??MST has a much faster convergence time than PVST+ due to the implementation of RSTP.Default convergence times drop from 50 secs down to msecs.
