OSPF LSA Types

Link State Advertisements (LSAs) are the building blocks of OSPF routing. Each type serves a specific purpose:

Type 1 - Router LSA

Describes router's links within an area.

Type 2 - Network LSA

Generated by DR for multi-access networks.

Type 3 - Summary LSA

Inter-area routes generated by ABRs.

Type 4 - ASBR Summary

Path to ASBR for external routes.

Type 5 - External LSA

External routes redistributed into OSPF.