OSPF advertising with interface secondary IP

[Suresh Babu]

HI All,

Need the clarification on below

I have done a lab scenario with 2 Routers and inter-connected both of them with Fa0/0

172.16.1.0/30 assigned to both the routers Fa0/0 as primary IP and 192.168.1.0/30 as secondary IP, Here I have advertised secondary IP subnet 192.168.1.0/30 in OSPF in both the routers but they are not forming the neighbor ship but I know when I advertise the primary IPs it will form

Can you guys clarify me the reason, why neighbor ship is not forming with secondary IPs and by what logic?

Regards

Suresh

[John Blakley · Accepted solution]

Ospf hellos are sourced from the primary address. You can still advertise the secondary subnet but adjacency Happens over primary address.

Hth,
John

Sent from Cisco Technical Support iPhone App

[Suresh Babu]

Thanks John for response.