4000 Router Series Layer 3 - IP Services Configuration Guide

DHCP overview

The Dynamic Host Configuration Protocol (DHCP) provides a framework to assign configuration

information to network devices.

Figure 10

shows a typical DHCP application scenario where the DHCP clients and the DHCP server

reside on the same subnet. The DHCP clients can also obtain configuration parameters from a DHCP

server on another subnet through a DHCP relay agent. For more information about the DHCP relay agent,

see "Configuring the DHCP relay agent."

Figure 10 A typical DHC

P application

DHCP address allocation

Allocation mechanisms

DHCP supports the following allocation mechanisms:

• Static allocation—The network administrator assigns an IP address to a client, such as a WWW

server, and DHCP conveys the assigned address to the client.

• Automatic allocation—DHCP assigns a permanent IP address to a client.

• Dynamic allocation—DHCP assigns an IP address to a client for a limited period of time, which is

called a lease. Most DHCP clients obtain their addresses in this way.