OSPF adjacency between loopbacks over Layer2 WAN

[Muhammad Rafi]

Hi Experts,

I am wondering if some can explain me below scenario please

you have two routers in different DCs and they only have layer 2 connectivity, hence no the IP addresses assigned to their outside interface, they both have 1 loopback on each router and I want to form an adjacency between their loopbacks.

Can anyone explain, how to achieve this, or redirect me to the relevant cisco documentation please.

[Akash Agrawal]

Hi,

We are talking about running a layer3 routing protocol between two DC. Do you have layer3 connectivity between them? Are you able to ping eachother loopback ips. I guess not. If they have layer2 connectivity, then physical port would be either access port or trunk port. In any case we can pass one vlan and configure a SVI interface (interface vlan <vlan-number>) for that vlan. Assign /30 ip address and over this you can have OSPF adjacency.

--Pls dont forget to rate helpful posts--

Regards,

Akash

[Muhammad Rafi]

Thanks Akash, 

Here is the scenario attached, this is for anyone who is interested, 

Yes, there is no IP assigned on to the eth0 interfaces and loopbacks have different subnets

if possible, would you please provide me the config

[Rajeev Sharma · Accepted solution]

Hey,

Just adding my bit to post. You may also explore ip unnumbered option, have a look:

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst4500/12-2/50sg/configuration/guide/Wrapper-46SG/unnumber.html

HTH.

Regards,

RS.

[Muhammad Rafi]

Thanks Rajeev for the link, I will have a look.