Hi,

I was just wandering whether there are some special cases where Type-4 ASBR 
summary LSAs are needed -and if they are needed at all?

Fact is Type-4 LSAs are only advertised by ABRs to all their regular areas 
including BB-area (omitting stub-kind of areas)

What I have noticed though is that if the ABR happens to be an ASBR as well -it 
won't advertise itself as ASBR -will not send Type-4 LSA

So I have created a setup with area 0 and area 1 with one ABR between them and 
on that ABR I redistributed one of my connected loopbacks
Routers within area 0 and routers within area 1 only had type-5 lsa with the 
external network but no type-4 lsa saying who the ASBR is
The ping worked as I thought

The point is advertising router id is in Type-5 LSA anyway making it clear 
who's the ASBR
So why all the ABRs have to mention it redundantly in Type-4 LSA?


Adam Vitkovsky CCIP(r) CCNP(r) certified
System Engineer | AT&T Business Solutions - Global Customer Service
Phone: +421-269-257-375
Email: [email protected]<mailto:[email protected]>

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