Routers can route in a two basic ways. They can use preprogrammed static routes, or they can dynamically calculate routes using any one of a number of dynamic routing protocols. Dynamic routing protocols are used by routers to perform discover routes. Routers then mechanically forward packets (or datagrams) over those routes.
Statically programmed routers cannot discover routes; they lack any mechanism to communicate routing information with other routers. Statically programmed routers can only forward packets using routes defined by a network administrator.
In addition to static programming of routes, there are three broad categories of dynamic routing protocols:
The primary differences between these ...