[c-nsp] OSPF flaps

[Jason Berenson]

Greetings,

I'm seeing a weird OSPF flap issue between a bunch of 7206's and a 
6513.  We're running fast OSPF between them all.  Here's some sample config:

7206:

router ospf 1
 router-id 0.0.1.10
 log-adjacency-changes
 area 0 authentication
 redistribute connected metric-type 1 subnets
 redistribute static metric-type 1 subnets
 redistribute bgp 65010 metric-type 1 subnets route-map global
 network 10.11.1.0 0.0.0.255 area 0
 network 10.12.1.0 0.0.0.255 area 0
!
interface GigabitEthernet0/2
des primary net
 ip address 10.11.1.10 255.255.255.0
 no ip redirects
 ip route-cache flow
 ip ospf authentication-key 7
 ip ospf cost 1
 ip ospf dead-interval minimal hello-multiplier 4
 duplex auto
 speed auto
 media-type rj45
 no negotiation auto


6513:

router ospf 1
 router-id 0.0.1.24
 log-adjacency-changes
 no capability lls
 area 0 authentication
 passive-interface default
 network 10.11.1.0 0.0.0.255 area 0
 network 10.12.1.0 0.0.0.255 area 0
!
interface GigabitEthernet9/1
 no ip address
 speed 1000
 duplex full
 switchport
 switchport access vlan 11
 switchport mode access
!
interface Vlan11
 description << PRIMARY NET >>
 ip address 10.11.1.24 255.255.255.0
 no ip redirects
 no ip mroute-cache
 ip ospf authentication-key 7
 ip ospf cost 1
 ip ospf dead-interval minimal hello-multiplier 4
!


There is IP connectivity between the two routers of course.  We leave 
all ints as passive by default and turn on each int as we need them to 
speak OSPF.  When I turn on vlan 11 as non passive, things come up then 
start flapping very rapidly at which point the 6513 becomes completely 
unresponsive.  Here's some output from the 7206's logs:

Mar  2 19:07:07 pri.core.router1 37224: Mar  2 19:07:04: %OSPF-5-ADJCHG: 
Process 1, Nbr 0.0.1.24 on GigabitEthernet0/2 from 2WAY to DOWN, 
Neighbor Down: Dead timer expired
Mar  2 19:07:07 pri.core.router2 2556211: Mar  2 19:07:04: 
%OSPF-5-ADJCHG: Process 1, Nbr 0.0.1.24 on GigabitEthernet0/2 from 2WAY 
to DOWN, Neighbor Down: Dead timer expired

The timers are matched up on all the routers, and there's of course no 
packet loss.  I don't see why the dead timers are expiring causing this 
to keep flapping.  Any input would be greatly appreciated.

Thanks,
Jason