Internet Core Protocols: The Definitive Guide

IP in Action

Although IP is responsible only for getting datagrams from one host to another, one network at a time, this seemingly simple service can actually get quite complex. An IP device has to route traffic to the appropriate network whenever a datagram needs to be forwarded; it has to break large datagrams into smaller pieces whenever datagrams have to be sent across a small network; and it has to make decisions based on the priority of the data.