XRRP and OSPF

[Dave Vinluan]

We are currently designing a partial mesh topology with 6 x 3400cl's, kindly refer to att.
Our network currently has 3 VLANS with one of them QoS'd w/ priority 7. While doing research (mostly online) we've come across conflicting information as when to use Virtual Routing over OSPF and when not to. Is there any industry norm when these two features should be used at the same time on the same network?

[André Beck]

Dave,

XRRP and OSPF fill entirely different purposes in a network so the easy answer is "use them both where you need them both".

While OSPF is an IGP and as such allows *Routers* to dynamically establish an optimal routing topology (and to react to change, where the most relevant source of change actually is losing a link or a device in a redundant topology and establishing alternate routes, so actual high availability emerges), XRRP is an FHRP (first hop redundancy protocol, AKA default gateway redundancy protocol) and deals with those devices in your network that are *Not* routers, which is essentially every access device (servers, clients, phones etc). These devices typically don't participate in the IGP and thus cannot fully benefit from the high availability it could provide, and that's exactly where an FHRP comes in handy.

If you look for some reading that really clarifies industry best practices in this area, I always like to point to http://www.cisco.com/go/srnd - especially look for the high availability campus design guides there.

HTH,
Andre.