A statically defined route is a route is manually entered into the router. The purpose of this is to add routes
to a router's routing table. Thus, static routing consists of individual configuration commands that define a
route to a router. A router can forward packets only to subnets in its routing table. The router always knows
about directly connected routes. By adding static routes, a router can be told how to forward packets to
subnets that are not attached to it.
A static route can be entered into the router in global configuration mode with the following command:
ip route destination_ip_address subnet_mask
{ ip-address | interface } [ distance ]
In the ip route command, the destination_ip_address and subnet_mask is the IP address and subnet
mask for the destination host. The ip-address parameter is the IP address of the next hop that can be used
to reach the destination and interface is the router interface to use. The optional distance parameter
specifies the administrative distance.
The advantages to using static routes in an internetwork are the administrator has total control of what is in
the routers routing table and there is no network overhead for a routing protocol. The disadvantage of using
only static routes is they do not scale well.