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unable to change OSPF area on 3750 layer 3 devices

Our project was to change a branch network from a common OSPF area (area 2) to branch specific areas. We made all of the necessary head end changes on our ASR platform and then to the primary 3945 WAN router at the first branch. We successfully established OSPF adjacencies across the WAN on the new OSPF area (area 4). However, when we attempted to make the changes on the next branch device, a 3750X-48PS, layer 3 access switch, we were unable to establish any adjacencies with the 3945 WAN device. We cleared the OSPF process but this did not fix the problem. This is the output from the "sh ip ospf database sum" on the access switch:

OSPF Router with id (169.x.x.x) (Process ID XXXXX)

Router Link States (area 0.0.0.2)

Link ID               Adv Router          Age           Seq #               Checksum         Link Count

169.x.x.x             169.x.x.x           2833          0X80001A9B      0X00615D          6

169.x.x.x             169.x.x.x            540           0X80001A7A      0X00A748          5

Router Link States (area 4) 

169.x.x.x             169.x.x.x           1407          0X80000003       0X002D12          2

A "sh  log | inc OSPF" output showed the OSPF area changing to 4 but the adjacency was never formed across the new area. The only way to clear the original area (2) from the database was to reload the layer 3 access switch.

Has anyone come across a similar issue while migrating to a new OSPF area?

Everyone's tags (3)
1 REPLY

Re: unable to change OSPF area on 3750 layer 3 devices

Hello

Debug ip ospf adj

Also int the switch LAN interface or the routers interface

Int xx
Ip ospf ignore mtu

Res
Paul


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