There are two major types of routing
processes, static and dynamic. Static routing is programmed by the
network administrator to determine which path a packet must take to
reach its destination. The administrator must maintain (including any
kind of changes, additions or deletions) the routes of each network
routing device. Static paths are not flexible with changing network
environments. Once the static routes are programmed, the determined
paths for packets do not change, regardless of changing network
conditions. Static routes are most often used for security reasons.
Dynamic routing allows the router to
select which path a packet must take in order to reach its
destination. In doing so, a router uses routing protocols such as
Routing Information Protocol (RIP), IGRP, EIGRP, or Open Shortest Path
First (OSPF) to communicate with other routers to determine which
path is the fastest way to transport data across an internetwork (a
network of networks). Using the routing protocols, routers
"talk" to each other to update what paths are best to send
data through, especially while network conditions are constantly
changing. Without routing or its protocols, large networks, such as
the Internet, would be impossible to maintain. 
|