Routing Protocol Functions

Cisco IOS software supports several IP routing protocols, performing the same general functions:

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1. Learn routing information about IP subnets from other neighboring routers.

2. Advertise routing information about IP subnets to other neighboring routers.

3. If more than one possible route exists to reach one subnet, pick the best route based on a metric.

4. If the network topology changes—for example, a link fails—react by advertising that some routes have failed and pick a new currently best route. (This process is called convergence.)

Note

A neighboring router connects to the same link as another router, for example, ...

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