In an OSPF Not-So-Stubby Area (NSSA), external routes can be introduced into the area by an NSSA Autonomous System Boundary Router (ASBR) as type 7 LSAs. These LSAs are unique to NSSA areas and allow for the injection of external routes in a limited fashion. An NSSA Area Border Router (ABR) then translates these type 7 LSAs into type 5 LSAs, which are propagated throughout the OSPF domain. References := Configure the OSPF Not-So-Stubby Area (NSSA) - Cisco