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Interesting OSPF Area 0 concept... posted 08/10/2006
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Hi group,

I have an interesting observation...

Setup (without Area0)

[rtrA]--(area10)--[rtrB] --(area20)--[rtrC]

router B is connected to router A via area 10 and router C via area 20.

We understand that router A and router C cannot see each other routes via
OSPF because there is no Area 0.

Setup (Loopback set to Area0)

[rtrA]--(area10)--[rtrB] --(area20)--[rtrC]

However if I create a interface loopback 0 and place in Area 0 in router B,
both router A and router C are able to see each other routes flagged as O IA.

Hence, can I assume that I can create a ABR router with 2 different interfaces
in 2 different areas and yet I can act as an ABR without using any
physical interfaces
to link both non-zero areas together?? Creating a loopback or any
available interface in
Area 0 seems to make it work. Or there is nothing special about it?? ;)