NSSA Translator Election & Forwarding Address

OSPF NSSA Translator Election & Forwarding Address 

• RFC 3101
• With OSPF NSSA, Type 7 NSSA External LSAs are translated to Type-5 External LSAs by the ABR connecting the NSA to Area 0.
• When multiple ABRs connect the NSSA to area 0, the ABR with the highest router-id is elected as the Type7 to Type 5 translator.

CONFIGURATION

• - Before changing anything, R5 has two ABRs routers which are R1 and R2 translated to Type 7 to Type 5,
• Translator selection is based on router-id. In this network design, R2's router-id is higher than Rotuer 1. In fact, R2 elected as Type 7 to Type 5 translator.