RIP redistribution into OSPF

Answered Question
Jun 2nd, 2009
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All,


I've attached a diagram for something that I ran into this morning. I have 2 ospf areas, one of which is an nssa, and I have a RIP router behind the nssa. I noticed that the same route that RouterB seen as an N2 route, RouterA sees as an E2 route. Is this because the ASBR is converting Type-7 LSA into a Type-5, and then RouterA is receiving the Type-5 LSA marking it as an external route, but not necessarily known that it came from an NSSA?


Thanks,

John

Correct Answer by Edison Ortiz about 8 years 3 weeks ago

To reiterate, Router A is not part of the NSSA so it will receive external routes as E1 or E2.


Router C is part of the NSSA (Area 1), so any external routes from a ASBR on that area (on this case router B) will be seen as N1 or N2.


HTH,


__


Edison.

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Edison Ortiz Tue, 06/02/2009 - 06:39
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John,


I don't see any diagram but if Router A is receiving this LSA via a regular area, it will see any external route as E2 instead of N2.


N2 LSAs will only be seen within the NSSA area.


HTH,


__


Edison.

John Blakley Tue, 06/02/2009 - 06:46
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Ugh...forgot to attach the diagram.


Is RouterB seeing the external route as N2 because it's configured with area 1 as the nssa?


Thanks!

John



Correct Answer
Edison Ortiz Tue, 06/02/2009 - 07:10
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To reiterate, Router A is not part of the NSSA so it will receive external routes as E1 or E2.


Router C is part of the NSSA (Area 1), so any external routes from a ASBR on that area (on this case router B) will be seen as N1 or N2.


HTH,


__


Edison.

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