thousands of routes is not necessary, and a default route
toward the next hop is sufficient.
There are several ways in which routing tables are
populated:
Directly connected networks
Static routes
Dynamic routes
Default routesWe’ve already discussed directly connected networks, in
which the router has an interface configured for that
network and is routing traffic for it and the default
routes, which are used as a last resort in the event that a
more specific route doesn’t exist in the routing table.
Static routes are configured manually by the network
administrator or the person managing a router. In small
networks in which there are not expected to be any
changes, static routes can work just fine. In larger
networks that are more dynamic in nature, with devices
and routers going offline and coming online constantly,
static routes do not work very well because the
administrator needs to manually change the entries as
the changes happen in the network. A much more
scalable solution in this case is dynamic routes.
Dynamic routes, as the name implies, are learned
dynamically through specialized software applications
called dynamic routing protocols. Several routing
protocols have been developed over the years, including
Open Shortest Path First (OSPF), Enhanced Interior
Gateway Routing Protocol (EIGRP), Routing
Information Protocol (RIP), Border Control Protocol
(BGP), and Intermediate System-to-Intermediate System
(IS-IS). Each of these protocols has its own