Bfd support for vrrp interface tracking query !

[Vaibhava Varma]

Hi All

I have a requirement in my typical LAN scenario whereby my LAN server connects in a dual homed fashion to two different LAN switches from a third party vendor. We are using vrrp for the server LAN. The two 3rd party vendor switches are uplinked via L3 links to two c6500. We are tracking the uplink interfaces under vrrp such that no traffic blackholing occurs if the uplink connectivity from master is broken. Now customer has asked to use bfd support in the vrrp uplink interface tracking which is supported by the vendor switches. This topic is confusing to me as what configuration would be required on c6500 to achieve this as the requirement is not to configure bfd for routing protocol but for vrrp interface tracking. As per my understanding BFD works only in integration with routing protocols and there would be no session formed by just enabling BFD under Interface Config. If anyone has any prior experience with implementing such setup please guide me on what needs to be done from c6500 side to achieve this. We are using static routes on c6500 for server LAN reachability and default route on vendor switches towards junos but no bfd for static routing.

Regards Varma

[Ivan Krimmel]

Hi Varma,

your understanding is correct, initially we were supporting BFD in conjunction with BGP/IGPs. Nowadays there's BFD support for VRRP in IOS XR and BFD support for HSRP in IOS. Since you're in multivendor environment, I don't think these options are feasible. You may instead apply subsecond hello timers in VRRP, provided you don't have lots of instances, you should not face a performance burden.

HTH,

Ivan.