Chapter . Routing

Routers

Whereas switches and bridges operate at OSI Layer 2 (the data link layer), routers primarily operate at OSI Layer 3 (the network layer). Like bridging, the primary act of routing involves moving packets across a network from a source to a destination. The difference involves the information that is used to make the forwarding decisions. Routers make decisions based on network layer protocols such as Internet Protocol (IP) and Novell NetWare Internetwork Packet Exchange (IPX).

Routing gained popularity in the mid- to late 1980s as a result of internetworks growing beyond the capability of bridges. Before this popularity, networks were relatively small and isolated, and bridges could handle the jobs of forwarding and segmentation. ...

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