I'm working on rolling out a redundant lan for a multipop cable co. Currently we're using all Cisco equipment for routers and UBRs, and HP switch gear for ethernet. We've got three pops, A, B, and C. Each pop has at least one UBR. Pop A is special as it has the border router for the network. The pops are wired with two sets of fiber, daisy chained, pop A to B, B to C. Right now we've got one half the fiber lit, and running ethernet over it. In each pop, there are two HP 4000M switches, which are not connected to each other, powering the fiber through gig-e transcievers. This gives us two redundant gig-e switched WANs in each pop running in parrael. As of right now, we're only riding on one of them, and only one is connected to the gateway router in pop A. All the routers/ubrs use OSPF to advertise/share routes amongst themselves and with our primary router which is at annother site, directly connected to the gateway router in pop A.
My first step in adding some redundancy is going to be throwing a crossover cable between the two switches in each pop and using HP switch meshing to keep from having loops. This will allow traffic to flow even if there is a single fiber cut between each pop. (The fiber is all on diverse paths physically so this should normally be the case.)
My second step would be to use the backup interface functionality of IOS to allow each router/ubr to straddle both switches, so should a switch loose power and go link dead, again, connectivity is not interrupted.
Problem is, this setup does me no good if a switch just hangs itself, but maintains link status on the connected ethernet links. The backup interface will never fire up under this scenario. Recovery would require manual intervention which I'm looking to avoid. HSRP looks to be out as afik it isn't designed to switch between interfaces on a single router. DSLw at first glance appears to be my solution, but I'm still digging. Does this seem like a good match, or should I be investigating something else?
If it helps, we have plans for a second diverse uplink to pop A and have no qualms terminating it in a second gateway router. We do need to loadbalance traffic across these two links however when possible. (IE if they are both up they both need to be utilized)