OSPF Message Types

Five types of OSPF Messages:

  • Hello
  • Database Description (DD or DBD)
  • Link-State Request
  • Link-State Update
  • Link-State Acknowledgement

OSPF LSDB and LSA

OSPF Link-State Database (LSDB)

  • Each router stores it’s LSA in it’s LSDB.
  • Each router within the same area should have the same LSDB information.
  • SPF algortithm for each area it is connected to.
  • The router thinks it’s the root of the tree and draws branches via SPF
  • LSAs in OSPF LSDB are pieces that the SPF process uses.
  • OSPF poisons LSA by setting max-age (3600).

OSPF types of Link State Advertisement (LSA)

  • Type 1: Router LSA
  • Type 2: Network LSA
  • Type 3: Summary LSA
  • Type 4: Summary ASBR LSA
  • Type 5: Autonomous system external LSA
  • Type 6: Multicast OSPF LSA
  • Type 7: Not-so-stubby area LSA
  • Type 8: External attribute LSA for BGP

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