OSPF stands for Open Shortest Path First.  This type of routing using a routing table that marks the number of hops.  As the number of hops increases, OSPF lowers the likelihood that the path will be used.  Hence OSPF means the shortest path is used first.

OSPF is similar to IBGP.  Its intent is to allow for multiple paths on a local network, where a backup network path is needed.  Both the main path and the backup path are put in the routing table and path switching can be almost immediate.

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