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October 02, 2005

NSSA (ABR+ASBR)

Sometime you face to a router in OSPF which is an ASBR NSSA and it's an ABR as well so in this situation you've two external LSAs on that router, one is LSA type 7 which is advertised to NSSA area and other is LSA type 5 which is advertised to other not stub area.
now in some case you don't need to advertise LSA 7 in NSSA area and you need the router acts as ABR router for NSSA area so to prevent advertising LSA 7 to NSSA area at Cisco routers you can use the following command under ospf process :
area area_id nssa no-redistribution
nssa-ospf.gif
at the above scenario you can see a router which is an ASBR NSSA router and an ABR router so to prevent IGRP advertisements (external routes) to NSSA area you should do by the below commands :
router ospf 100
area 1 nssa no-redistribution

Posted by Mehrdad at 10:20 AM