Routing Protocols

This section covers four main routing protocols:

  • RIP

  • EIGRP

  • OSPF

  • BGP

Before discussing the characteristic of each protocol, this section covers how routers (Cisco routers, in particular) generally route IP packets.

Routing is a process whereby a path to a destination host is selected by either a dynamic or static routing protocol. A routing protocol is an algorithm that routes data across the network. Each router makes routing decisions from host to destination based on specific metrics used by the operating routing protocol. For example, RIP uses hop count (commonly known as the network diameter) to decide what router interface the data is sent. A lower hop count is always preferred. OSPF, on the other hand, uses a cost metric; ...

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