Ok, I know there are many previous posts regarding STP, but could not find any that were exactly like my configuration, so here goes.
We have 2 6500's with 720's at the core, and another 6500 with a sup1a in another bldg, all with redundant links. We have 20 vlans. I was thinking about implementing Rapid PVSTP+, but my 3500XL switches don't support it. Can I run RPVST plus on the 6500's, and STP on the 3500's?, or should I just stick with PVST. The redundant links are important, but the faster convergence is not that critical. Please advise.