OSPF Overview
Upon initialization, each router records information about all its interfaces.
Each router builds a packet known as the Link State Advertisement (LSA).
- Contains a listing of all recently seen routers and their cost
- LSAs are restricted to being forwarded only in the orginated area
Received LSAs are flooded to all other routers.
- Each router makes a copy of the most recently “seen” LSA
Each router has complete knowledge of the topology of the area to which it belongs.
Adjacencies are formed between a Designated Router (and Backup DR) and other routers on a network.
Shortest Path Trees are constructed after routers exchange their databases.
Router algorithm only when changes occur (or every 30 minutes, whichever is shorter).