Allied Telesis AlliedWare Plus Operating System Version 5.4.4C (x310-26FT,x310-26FP,x310-50FT,x310-50FP) - Manual (Page 1688)

Dynamic Host Configuration Protocol (DHCP) Introduction
Software Reference for x310 Series Switches
63.2 AlliedWare Plus TM Operating System - Version 5.4.4C C613-50046-01 REV A
Introduction
This chapter describes the Dynamic Host Configuration Protocol (DHCP) support provided
by your device. This includes how to configure your device to:
■ act as a DHCP relay agent
■ use the DHCP client to obtain IP addresses for its own interfaces
BOOTP
Bootstrap Protocol (BOOTP) is a UDP-based protocol that enables a booting host to
dynamically configure itself without external interventions. A BOOTP server responds to
requests from BOOTP clients for configuration information, such as the IP address the
client should use. BOOTP is defined in RFC 951, Bootstrap Protocol (BOOTP).
RFC 1542, Clarifications and Extensions for the Bootstrap Protocol, defines extensions to
the BOOTP protocol, including the behavior of a DHCP relay agent.
DHCP
DHCP is widely used to dynamically assign host IP addresses from a centralized server that
reduces the overhead of administrating IP addresses. DHCP helps conserve the limited IP
address space because IP addresses no longer need to be permanently assigned to hosts.
DHCP centrally manages IP address assignment for a large number of subscribers.
DHCP is based on BOOTP, and is defined in RFC 2131. It extends the BOOTP mechanism by
providing:
■ a method for passing configuration information to hosts on a TCP/IP network
■ automatic allocation of reusable network addresses
■ other additional configuration options
DHCP is designed to interoperate with BOOTP clients and DHCP clients, without the
BOOTP clients needing any change to their initialization software.
DHCP Relay Agents
DHCP relay agents pass BOOTP and DHCP messages between servers and clients.
Networks where the DHCP or BOOTP server does not reside on the same IP subnet as its
clients need the intermediate routers to act as relay agents. A maximum number of 400
DHCP relay agents (one per interface) can be configured on the device. Once this limit has
been reached, any further attempts to configure DHCP relay agents will not be successful.