OSPF Areas (Part 6) - Totally NSSA
Links:
RFC 2328 – OSPF Version 2
RFC 3101 - The OSPF Not-So-Stubby Area (NSSA) Option
RFC 2740 – OSPF for IPv6
Cisco - OSPF Not-So-Stubby Area (NSSA)
Breakdown of the Totally NSSA Area:
Redistribution allowed by ASBRs
NSSA ASBRs generate Type-7 LSAs for external routes
Appear as N1 or N2 external
ABRs convert Type-7 LSAs to Type-5
Blocks Type-5 External, Type-4 ASBR and Type-3 Summary LSAs
Source: OSPF Areas (Part 6) - Totally NSSA (//)
From http://blog.movingonesandzeros.net/