1-11 IP Routing OverviewGo to these sections for information you are interested in:z Routingz Routing Protocol Overviewz Displaying and Maintaining a Routing TableThe term “router” in this document refers to a router in a generic sense or a Layer 3 switch.RoutingRouting in the Internet is achieved through routers. Upon receiving a packet, a router finds an optimalroute based on the destination address and forwards the packet to the next router in the path until thepacket reaches the last router, which forwards the packet to the intended destination host.Routing provides the path information that guides the forwarding of packets.Routing Table and FIB TableRouting tableRouting tables play a key role in routing.route selection and forwarding information bases (FIBs) play akey role in packet forwarding. Each router maintains a routing table, and each entry in the tablespecifies which physical interface a packet destined for a certain destination should go out to reach thenext hop (the next router) or the directly connected destinationFIB table at least.Routes in a routing table can be divided into three categories by origin:z Direct routes: Routes discovered by data link protocols, also known as interface routes.z Static routes: Routes that are manually configured.z Dynamic routes: Routes that are discovered dynamically by routing protocols.Dynamic routing protocol is not supported on the S5120-EI Series Ethernet Switches.Each entry in the FIB table specifies which physical interface a packet destined for a certain destinationshould go out to reach the next hop (the next router) or the directly connected destination.
