OSPF - Multiple OSPF Process with Same Interface (Sub-Interfaces)

[netbeginner]

Hello All, We are configuring OSPF with 03 VRF , on Same Interface (Cisco Router) divided into sub-interfaces. We are running 03 different OSPF process per VRF. We have configured only 1 Loopback in our router to use as router-id for all the OSPF processes. Unfortunately it's giving error while we are configuring router-id under OSPF process 2 and process 3 as it already accepted un OSPF process 1. We also tried VRF routes leaking also with no luck. please advise. Rgds ***

[Georg Pauwen]

Hello,

it won't work, even without VRFs. Each OSPF process needs a unique router ID.

[paul driver]

Hello

humm.   Vrfs are suppose to be separate routing instances as such you can use the same ip  addressing and I would have guessed this would have applied to ospf rids also !

However to make sure how are you creating the vrf for ospf - usually you would do this by:

router ospf 1 vrf xxx

res

Paul

[netbeginner]

Yes Paul, we are configuring OSPF with VRF like same as you shared. Only thing need to add is we are creating 03 different VRF with OSPF different processes.

For Eg .
router ospf 1 vrf xxx
network ............

router ospf 2 vrf yyy
network ...........

router ospf 3 vrf zzz
network ...........

We are trying to configure same router-id under all this OSPF processes and getting challenges as router-ID is not getting accepted for process 2 and 3

Hello George , R u Sure ??? that this above concept will not work.

Rgds
****

[paul driver]

Hello

Hum can you try and create 3 loopbacks same IP address but in 3 vrfs -  then try again?

EDITED - Just managed to lab this and indeed you CANNOT apply the same RID to each vrf process  even when these ip address overlap but are in separate routing instances, I would have thought it would be applicable, but I guess thinking about it any leaking between vrfs instances would probably cause issues! 

Apologies for mis-leading you - but it was something I really thought was applicable thing to do

res

paul

[Richard Burts]

I realize that the original poster had planned to use the same IP address as OSPF RID in all three processes. Now that we know that this will not work, is there a problem with creating a separate RID for OSPF 2 and 3? Note that they do not have to be interface IPs. They just need to be unique IP addresses.

HTH

Rick

[pzkqx6000]

Hello,

Maybe old threat...
I did not try to use a loopback interface as Router-id (without the command router-id), but if you manually configure it (in my case, it is like one SVI IP for one of those vrfs) you have no issues on using the same router-id for different OSPF process in different VRFs, as far as I know.

router ospf 1100 vrf A
 router-id 192.168.203.2
 passive-interface default
 no passive-interface Vlan1192
 network 172.23.107.1 0.0.0.0 area 0
 network 192.168.225.26 0.0.0.0 area 0
router ospf 299 vrf B
 router-id 192.168.203.2
 passive-interface default
 no passive-interface Vlan1815
 network 192.168.5.2 0.0.0.0 area 0
 network 192.168.212.33 0.0.0.0 area 0
router ospf 1 vrf C
 router-id 192.168.203.2
 redistribute static
 passive-interface default
 no passive-interface Vlan1763
 network 192.168.251.241 0.0.0.0 area 0
 network 192.168.251.250 0.0.0.0 area 0