[j-nsp] Strange VRRP problem -- question about restarting process

[John Neiberger]

We have a very odd problem that we've been dealing with for a couple of
weeks. JTAC is involved but we have not come to a resolution yet. The gist
of the problem is that we have two MX960s and we're running VRRP on
multiple interfaces with different Cisco switches in between each pair of
Juniper interfaces.

[J] ----- [C]----[C]------ [J]

The switches are just layer two and we're running VRRP on the routers. The
problem is that one day, three of the interfaces on the backup router
suddenly stopped receiving VRRP messages from its peer. JTAC seems to think
that the Cisco switches just suddenly stopped forwarding VRRP messages to
the backup router, but that makes zero sense unless some bizarre issue just
happened to occur on multiple unrelated switches at exactly the same
moment. I'm still leaning toward a problem on the router.

Which leads me to my question. What is the risk of restarting the VRRP
process? I see we have "soft" and "graceful" as options. Both sound fairly
low-risk. I'm tempted to just restart the process on the backup router to
see if that fixes the problem.

What do you think?

Thanks,
John