Routing is the process of moving traffic across an internetwork from one place to another. Intermediate devices called routers (or gateways) determine the traffic’s path along the way. Routing is often confused with bridging in that both are responsible for making forwarding decisions. However, routing involves Layer 3 (network) decision-making, whereas bridging makes decisions based on Layer 2 (data link) information.
Routers perform two basic functions:
Routers use metrics to determine optimal paths in a network. Metrics can range from the bandwidth of a particular path to the relative distance of one router from another. Routers maintain ...