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OSPF Link LSA and Intra-Area-Prefix : LSA Type 8 and LSA Type 9

July 25, 2020 ,
OSPFv3 brings a few changes in the LSA types. How packet OSPFv2 exchanges LSA in order to exchange self originated routes is discussed here. OSPFv2 exchanges IPv4 routes with the help of LSA 1 (Router LSA). This helps to propagate the route. In a broadcast segment it exchanges LSA 2 (Network LSA). 

Let's have below topology, the IP address and the topology showing below is for the demo purposes and have no relevance with any of the enterprise networks.

Fig 1.1- OSPFv3- LSA's


What does the router send when OSPF process needs to exchange IPv6 routes? In order to fulfill this requirement, two new LSAs are added which help exchange IPv6 routes 

LSAs that are responsible to carry IPv6 Routes:
  • LSA Type 8: Link LSA
  • Link Local scope: LSA is only flooded on the local link and is further used for the LINK-LSA
  • LSA Type 9: Intra-Area LSA
  • Area Scope: LSA is only flooded throughout a single OSPF area. Used for router-LSA, Network-LSA, inter-area-prefix-LSA, inter-area-router-LSA and intra-area-prefix-LSA
Example
Type-3 summary LSA have been renamed inter-area-prefix-LSA
Type-4 summary LSA have been renamed inter-area-router-LSA

   Configurations on router R1

A new LSA called the intra-area-prefix-LSA has been introduced. This LSA carries all IPv6 prefix information that in IPv4 is included in router LSA and network LSA.