OSPF

[jonk34567]

if i do not configure an router id in ospf it will take the loopback or physical interface as router id.so always ospf process will have a router-id or can it function without router id 

[Joseph W. Doherty · Accepted solution]

It needs to have a router-ID.

[ABINTHOMAS6431]

Router must have a router ID.It can not communicate in the network without a router ID.

The router ID is just like your name... The purpose of name is to identify you in a group. Without a name you can not get identified in a group of people(your name is an identity). Just like this the router also needs an identity (i.e router ID) to distinguish from each other.