OSPF on Cisco router 4331 with internal switch module

[MARTIN FUNKE]

Hello,

I have set up an internal switch in a cisco 4331 router with an internal connection with BDI interface on the router and interface vlan 20 on the switch module.

I have configured both interfaces with an ip address each within the same subnet. Ping is running from both sides.

On both sides I have configured ospf process 1 and the interfaces in area 42 with the network command.

I see some ospf hello packet sent and received on both sides but the neighborship wont come up.

w-lvn-dvs-lbme-k-sw-1#sh ip ospf nei

Neighbor ID     Pri   State           Dead Time   Address         Interface
172.16.18.80      1   DOWN/DROTHER       -        172.18.67.5     Vlan20
w-lvn-dvs-lbme-k-sw-1#

w-lvn-dvs-lbme-k-1#sh ip ospf nei

Neighbor ID     Pri   State           Dead Time   Address         Interface
172.16.18.81      1   EXCHANGE/DR     00:00:37    172.18.67.6     BDI1
w-lvn-dvs-lbme-k-1#

Has anybody an idea what went wrong?

Best regards,

Martin Funke.

[Richard Burts]

There is not enough information here to be sure what is the issue. Can you post the configuration?

HTH

Rick

[Mark Malone · Accepted solution]

Hi
does the MTU match on each neighbor side ?

[MARTIN FUNKE]

That is the solution. As soon as I adjusted the mtu size on the router the ospf neiborship came up.
Thank's a lot Mark.

[Mark Malone]

ah great thats good , thanks for marking it may help someone else