BFD vs NSF in VSS

[Peter Koltl]

Are BFD and NSF mutually exclusive in a Cat6800 VSS? BFD detects link failures rapidly and tears down the OSPF adjacency but NSF would need some seconds to let standby supervisor take over.

[Philip D'Ath]

I don't know, but I would not think so.

BFD detects one way (or two way) link failures quickly.  It can be used with OSPF, but that is not to imply it is only intended for this.

I would hope you would have at least two links between chassis if you are using VSS.  It should be a rare event you get a double link failure while both chassis are still working.

NSF is concerned with non-stop forwarding when (in this case) there is a supervisor failure, rather than single link failure.  If you have a double link failure you are in for a world of pain.