OSPFv2 vs OSPFv3 LSA’s

By | February 2, 2014

In this post we will talk bout the differences between OSPFv2 and OSPFv3 LSA’s

An LSA (Link state advertisement) is a packet-type used by OSPF to communicate information about to network to its neighbors. OSPFv2 uses a number of different LSA’s as listed below.

LSA Type 1 – Router LSA – Generated by all routers in OSPF and flooded within a single area. Gives information about local links and subsets of that router. Also contain the routes RID.

LSA Type 2 – Network LSA – Generated by the DR on a multi-point network type. List all attachments to the DR.

LSA Type 3 – Network Summary LSA – Generated by the ABR and send to attached areas containing information about destination prefixes for a area.

LSA Type 4 – ASBR Summary LSA – Generated by that ABR containing a route to the ASBR so other routes have a way of the OSPF domain.

LSA Type 5 – External LSA – Generated by the ASBR containing routes outside the OSPF Domain. An example of this is routes redistributed from another routing protocol.

LSA Type 6 – Group Membership LSA- used for MOSPF

LSA Type 7 – NSSA External – Smiler to Type 5 but is generated by a ASBR in a Not-so-stubby area type.

LSA Type 8 – External-Attributes-LSA – Uses to carry BGP ASN

LSA’s Type 9,10 and 11 – Opaque LSA.

LSA Type 9 is ues for OSPF graceful restart and LSA Type 10 is ues for MPLS TE

Like OSPFv2, OSPFv3 Carries IPv4 prefixes but also caries IPv6. Now we will have a look at OSPFv3 LSA (RFC 5340)

LSA Type 1 –  Router LSA – Generate by all OSPF router giving information about itself. Flooded within an area. (0×2001)

LSA Type 2 – Network LSA – Generated by the DR on a multi-point network type. List all attachments to the DR. (0×2002)

LSA Type 3 – Inter-area-prefix LSA – Generated by a ABR and contains information on prefixes form other areas. (0×2003)

LSA Type 4 – Inter-area-router LSA – Generated by an ABR providing information of ASBR. (0×2004)

LSA Type 5 – As-External LSA – Same as OSPFv2 Generated by the ASBR containing routes outside the OSPF Domain. An example of this is routes redistributed from another routing protocol. (0×4005)

LSA- Type 6 – Deprecated

LSA Type 7 – Type-7 LSA – As above Generated by ASBR’s within a NSSA. (0×2007)

LSA Type 8 -Link – Generated by all OSPF routers. Carries information about links and assisted address. Flooded between links. (0×0008)

LSA Type 9 – Intra-area-prefix – Generated by OSPF routers in an area providing information about  links and address associated. (0×2009)

Along with this there is also a flooding scope including with the OSPF LSA packet  in OSPFv3. This is as follows

S2  S1  Flooding Scope

0   0     Link Local
0   1     Area
1   0     Autonomous System
1   1     Reserved