Chapter 15 / 15.5 / 15.5.4

15.5.4 Choosing The Best Route

A destination network can often be reached by several different paths.

Routers therefore use routing metrics to determine which route should be preferred. Depending on the routing protocol, these metrics may consider factors such as:

• the number of intermediate routers;
• available bandwidth;
• communication delay;
• link reliability; and
• administrative preference.

The selected route is not necessarily the physically shortest path. Instead, it is the path that best satisfies the objectives of the routing protocol and network administrator.

If network conditions change, dynamic routing protocols automatically update routing information so that packets can be redirected along more suitable paths.