Ospf LSA types and flooding

Link State Advertisement Types

• LSA Type 1 - Router LSA
• LSA Type 2 - Network LSA
• LSA Type 3 - Network summary LSA
• LSA Type 4 - ASBR Summary LSA
• LSA Type 5 - AS External LSA
• LSA Type 6 - Group Membership LSA
• LSA Type 7 - NSSA External LSA
• LSA Type 8 - External Attributes LSA
• LSA Type 9 - Opaque LSA (link-local scope)
• LSA Type 10 - Opaque LSA (area-local scope)
• LSA Type 11 - Opaque LSA (AS scope)

LSA Flooding :

If the egress interface is a point-to-point or point-to-multipoint OSPF network type then the LSA will be received directly by the neighboring router and it will propagate it further by flooding it through all remaining interfaces. If the egress interface is a broadcast or nonbroadcast multiaccess OSPF network type then the LSA is first sent to the DR/BDR (224.0.0.6) on the network segment, and the DR will then in turn send the LSA out all its interfaces including the one that has received the LSA (but addressed to a different IP address 224.0.0.5).