Most of the time, static routes over serial point-to-point networks
can easily avoid recursive route lookups by using an exit interface instead of
the intermediate or next-hop address. Figure
shows an example
of creating a static route on RouterB for RouterA LAN, using an exit interface
instead of an intermediate address.
Examine how this route was installed
in the routing table, as shown in Figure
.
Instead of using an intermediate address, this route is resolved with the
exit interface, Serial0/0 that was configured with the static route command.
The routing process, using this single entry, can forward any packets destined
for the 172.16.1.0/24 network. No recursive route lookups are needed. Because
only a single routing table lookup is needed, instead of multiple, recursive
lookups, this type of static route will increase performance of the routing
table process.
Notice that the routing table states that this static
route is "directly connected."
S 172.16.1.0
is directly connected, Serial0/0
In the case of a
static route, "directly connected" means that the static route was
configured with an exit interface. This does not mean that it is a directly
connected network of an interface on the router. Like all static routes, the
default administrative distance of this static route is still 1.