Introducing OSPF

Open Shortest Path First (OSPF) is an Interior Gateway Routing Protocol and uses the concept of Autonomous Systems (AS). AS is either a single network or a group of networks controlled by a common network administrator (or organization). Each router has an identical database that includes information on:

  • The single router
  • The current state of a router
  • The state of the router's interfaces
  • Reachable neighbors

The aforementioned database is called Link State Database (LSDB) and is built on each OSPF router receiving LSA (Link-state advertisement , the base communication of the router's local routing topology) from every other router in the same AS. To keep track of LSAs in the LSDB, each router is assigned a router ID. It is a 32-bit ...

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