·
Type
1 – Router LSA: The Router LSA is
generated by each router for each area it is located. In the link-state ID you
will find the originating router’s ID.
·
Type
2 – Network LSA: Network LSAs are
generated by the DR. The link-state ID will be the router ID of the DR.
·
Type
3 – Summary LSA: The summary LSA is
created by the ABR and flooded into other areas.
·
Type
4 – Summary ASBR LSA: Other routers need
to know where to find the ASBR. This is why the ABR will generate a summary
ASBR LSA which will include the router ID of the ASBR in the link-state ID
field.
·
Type
5 – External LSA: also known as
autonomous system external LSA: The external LSAs are generated by the ASBR.
·
Type
6 – Multicast LSA: Not supported and
not used.
·
Type
7 – External LSA: also known as
not-so-stubby-area (NSSA) LSA: As you can see area 1 is a NSSA
(not-so-stubby-area) which doesn’t allow external LSAs (type 5). To overcome
this issue we are generating type 7 LSAs instead.
Credit - Networklessons.com
