both a type-5 and a type-7 LSA for the same network. The type-5 LSA will be flooded to the . backbone and the type-7 will be flooded into the NSSA. If this is the case, the P-bit must be . reset (P=0) in the type-7 LSA so the type-7 LSA isn’t again translated into a type-5 LSA by . another NSSA ABR. Note: P = Propagate

Below we can see that R2 translates the LSA Type 7 into LSA Type 5 because the P-bit set by R3 and floods this LSA Type 5 into area 0: R2#show ospfv3 database external . OSPFv3 1 address-family ipv4 (router-id 2.2.2.2) Type-5 AS External Link States . LS age: 1229. LS Type: AS External Link. Link State ID: 0. Advertising Router: 2.2.2.2

When a type-5 LSA and a type-7 LSA are found to have the . same type and an equal distance, the following priorities . apply (listed from highest to lowest) for breaking the tie. a. Any type 5 LSA. b. A type-7 LSA with the P-bit set and the forwarding . …

When a type-5 LSA and a type-7 LSA are found to have the. same type and an equal distance, the following priorities. apply (listed from highest to lowest) for breaking the tie. a. Any type 5 LSA. b. A type-7 LSA with the P-bit set and the forwarding. address non-zero. c. Any other type-7 LSA.

LSA Type 3: Summary LSA; LSA Type 4: Summary ASBR LSA; LSA Type 5: Autonomous system external LSA; LSA Type 6: Multicast OSPF LSA; LSA Type 7: Not-so-stubby area LSA; LSA Type 8: External attribute LSA for BGP . Like Steven said, these are just headings for each LSA type, if you want to dig deeper you issue commands like:

The nssa-only keyword instructs the NSSA ASBR R3 to advertise the LSA Type 7 with the P-bit cleared, therefore, it prevents the translation of the LSA 7 into the LSA 5 on the NSSA ABR R2: R2#show ipv6 ospf database nssa-external . OSPFv3 Router with ID (2.2.2.2) (Process ID 1) Type-7 AS External Link States (Area 1) Routing Bit Set on this LSA ...

If the NSSA*s ABR receives a type 7 LSA with the P-bit set to one, it will translate the type 7 LSA into a type 5 LSA and flood it throughout the backbone area, It the P-bit is set to zero, no translation will take place and the destination in the type 7 …

The ASBR will inject the Type 7 LSA into Area 1 in your diagram. The ABR RTR-2 will inject the Type 7 converted to the Type 5 LSA, into Area 0. Type 7 LSA is flooded only in the NSSA area. So, it's the Type 5 LSA from there on that gets propagated outside the NSSA area and this Type 5 LSA carries the forwarding address.

Ok, I am now really confused. From my understanding LSA Type 7 is only generated by an ASBR inside a NSSA to describe external routes redistributed into the NSSA from outside the AS. If this is so, than how can any ABR send its default routes as LSA Type 7s? I am going to need to see some debug outputs showing this LSA Type 7. Brian "Dazed ...

Hi Steven, it all makes sense to me now. The external prefixes will not show up in the NSSA area as type 7 LSA if the NSSA ABR is not doing redistribution into the NSSA. The other thing i noticed was that even type 3 LSA of those loopback prefixes will not show up in the NSSA; thats the whole point of having an NSSA.