VTP, Portfast, Spanning Tree and all the other switch related stuff.
http://www.ietf.org/rfc/rfc1587.txt4.1 Translating Type-7 LSAs Into Type-5 LSAs This step is performed as part of the NSSA's Dijkstra calculation after type-5 and type-7 routes have been calculated. If the calculating router is not an area border router this translation algorithm should be skipped. All reachable area border routers in the NSSA should now be examined noting the one with the highest router ID. If this router has the highest router ID, it will be the one translating type-7 LSAs into type-5 LSAs for the NSSA, otherwise the translation algorithm should not be performed.