I have 2-6509's connected by gigabit at the core with MSFC's. I have 4000's in the campus building closets connected gigabit to each core switch. Each 4000 is it's own VLAN and the gig links are VLAN members, not trunks back to the core switches. HSRP is running between the MSFC's for each VLAN, each has it's own HSRP group indentifier. The core switch with the active MSFC for a specific VLAN is also the root bridge. It was up and running stable for about a year, but every once in a while I get a duplicate IP address error on an MSFC and the IP address is always one of the VLAN's interface's on the MSFC. I have to shut down the interface and all resumes well. There is no real duplicate IP out there. I find documentation that says there is probably a STP issue but I can't seem to find one. This has happened to several buildings in the last 6 months. Suggestions would be greatly apperciated.
