VSS and OSPF during a VSS failover ( OSPF completely drops )

[graham smart]

Hi Guys,

I'm having terrible problems with a new VSS setup I have going at the moment.

It consists of :

2x 7600's for the core

2x 6500's for the vss

Anyway,

When I do a failover, it fails over fine but OSPF seems to drop and then come back.

The VSS has MEC's going to the 7600's so when one VSS-switch dies, only one uplink in a MEC is down.. The port-channel is up so in reality OSPF should stay up?

The problem I had is that we get a good 5 to 30 seconds worth of outage when a failover happens and I cant seem to find a reliable config to get this to stay up happily.

Any thoughts?

Base OSPF config on the VSS = :

router ospf 7

router-id x.x.x.x

log-adjacency-changes

auto-cost reference-bandwidth 10000

nsf

nsf cisco helper disable

passive-interface default

network 0.0.0.0 255.255.255.255 area 0

default-information originate

Base OSPF on the 7600's:

router ospf 7

max-metric router-lsa on-startup 120

log-adjacency-changes

auto-cost reference-bandwidth 10000

network 0.0.0.0 255.255.255.255 area 0

Thanks

G

[martin.foote]

Yep, we've got it on both. Some complication is our P's aren't Cisco.

The PE device

PE#sh ip bgp vpnv4 all neighbors …

    Graceful Restart Capability: advertised and received

The P devices

P1#sh ip bgp vpnv4 neighbors ...

       GracefulRestartCapability: Received

       GracefulRestartCapability: Sent

P2#sh ip bgp vpnv4 neighbors ...

       GracefulRestartCapability: Received

       GracefulRestartCapability: Sent

[graham smart]

Hmmm

As one of the others said to me.

It may be worth enabling debugs on the protocol and then doing a failover to see why / what one is causing the issue.

Hopefully something will jump out in  the debug?

[martin.foote]

Tested it with a Cisco RR and we've cut two minutes down to 10 seconds with default graceful restart settings. Planning on doing some more testing to try and reduce it further but certainly looks a lot better!

It's quite clear the routes are marked as S (Stale) during the failover on the Cisco RR, on the other kit they were instantly removed.

Thanks for your assistance with this and good luck with your change!