Solved: OSPF Stub / NSSA

acbenny · ‎02-25-2007

Hi Expert,

In OSPF type, Can Stub area can be connected to other routing protocol ( e.g. RIP, IGRP) ?

If No, is it NSSA need to replace stub area to do it ?

sundar.palaniappan · ‎02-25-2007

When another routing protocol/process, static/connected routes are redistributed into OSPF the router advertises them as external, type 5, LSAs. External routes can't exist in stub area.

NSSA, not-so-stubby area, is designed to address this limitation. That is, another routing protocol/process, static/connected route can be redistributed into OSPF stub area but they are advertised as type 7 LSAs. ABRs transalate the type 7 LSA to type 5, external, LSAs and advertise it to the rest of the OSPF domain.

HTH

Sundar

View solution in original post

sundar.palaniappan · ‎02-25-2007

When another routing protocol/process, static/connected routes are redistributed into OSPF the router advertises them as external, type 5, LSAs. External routes can't exist in stub area.

NSSA, not-so-stubby area, is designed to address this limitation. That is, another routing protocol/process, static/connected route can be redistributed into OSPF stub area but they are advertised as type 7 LSAs. ABRs transalate the type 7 LSA to type 5, external, LSAs and advertise it to the rest of the OSPF domain.

HTH

Sundar

acbenny · ‎02-25-2007

Thx ! Sundar.

As a result, can I conclude that my previous posted message is correct

sundar.palaniappan · ‎02-25-2007

Yes, that would be correct.

HTH

Sundar