OSPF ABR Functions

[yvarzari]

Hello,

I have few OSPF questions regarding ABR.

Which are OSPF ABR functions:

- flooding Summary LSAs to connected areas?

- flooding ASBR Summary LSAs to connected areas?

- flooding NSSA External LSAs to Area 0?

- performing summarization on routes headed to Area 0?

Thanks!

[rais]

All of 'em.

HTH.

[azad.ali75]

The correct answers are-

- flooding Summary LSAs to connected areas.

-flooding ASBR Summary LSAs to connected areas.

[e.ciollaro]

ABRs:

• flood LSA-5 to other Area 
• create and inject in Area 0 LSA-3 and LSA-4 for non-backbone area  (discovering ASBR checking info in LSA-1)
• flood LSA-3 and LSA-4 from Area 0 to non-backbone areas changing metric and Advertising Router Id
• make LSA-7 to 5 translation
• create LSA-3 for default route and inject it in stub areas

Moreover ABRs might are used to terminate virtual-link for non backbone areas not directly connected to Area 0

Bye,

e

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