OSPF Troubleshooting

Mathieu Rochette · ‎12-06-2011

Hello,

I have some problems with OSPF on two routers cisco: one 3845 and one 881.

The OSPF is going DOWN every 30min and return in state LOADING to INIT in 2 minutes after going DOWN.

Here is our configuration:

Cisco 3845:

BI-LOT-C3845-001#sh run int gigabitEthernet 0/0.1017

Building configuration...

Current configuration : 306 bytes

!

interface GigabitEthernet0/0.1017

encapsulation dot1Q 1017

ip vrf forwarding VRF1

ip address 172.20.1.177 255.255.255.248

ip mtu 1496

service-policy input INGRESS-ADA-SITES

service-policy output PM_SHAPING-ADA-SITES-1MO

end

router ospf 3 vrf ADAPEI

router-id 192.168.255.252

log-adjacency-changes

redistribute connected subnets

network 172.20.1.176 0.0.0.7 area 0.0.0.0

default-information originate

interface Loopback2

description Loopback VRF1

ip address 192.168.255.252 255.255.255.255

Cisco 881

interface Loopback0

ip address 192.168.252.105 255.255.255.255

interface FastEthernet4

ip address 172.20.1.178 255.255.255.248

ip mtu 1496

duplex auto

speed auto

router ospf 3

router-id 192.168.252.105

log-adjacency-changes

redistribute connected subnets

network 172.20.1.176 0.0.0.7 area 0.0.0.0

default-information originate

When we debugg the ospf process on the 881 we see the router trying to send hello but It receive no hello packet from 3845 but it's not a connectivity loose because if we run a ping there is no loss.

On the other side, 3845 router continue to send end receive correctly the hello packet from the 881 then the 881 only send hello packets.

Thanks for you're help.

Regard,

Mathieu Rochette

Marwan ALshawi · ‎12-06-2011

Loopback interface in the 3845 isnt in the same vrf !

Trynto add the command ospf ignore mtu on both routers if any difference but I don't think this is the issue

Trynto debug ospf Neigbor and events on both routers and reset the ospf proccess and see what error you get

Mathieu Rochette · ‎12-06-2011

Hello,

Thanks for the reply, we will try to add this changes in our config file.

But do you have an idea for what the router is doing all 30min ?

Regarrds, Mathieu Rochette.

EDIT: I've add the logs in attachment with the dead-timer modified from 2min to 3 min, the OSPF neighbor don't became down but we have always the 881 sending hello and dont receive any hello. The 3845 send and receive hello packet normally. This problem occur every 30min.