H3C Technologies H3C S10500 Series Switches - Manual (Page 66)

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DHCP relay agent configuration
NOTE:
The DHCP relay agent configuration is supported only on Layer 3 Ethernet ports (or subinterfaces), VLAN
interfaces, and Layer 3 aggregate interfaces.
Introduction to DHCP relay agent
Application environment
Via a relay agent, DHCP clients can communicate with a DHCP server on another subnet to obtain
configuration parameters. DHCP clients on different subnets can contact the same DHCP server rather
than having a DHCP server on each subnet. This centralizes management and reduces cost reduction.
NOTE:
An MCE device serving as the DHCP relay agent can forward DHCP packets not only between a DHCP
server and clients on a public network, but also between a DHCP server and clients on a private network.
Note that the IP address ranges of the public and private networks or those of private networks cannot
overlap each other. For more information about MCE, see the
MPLS Configuration Guide.
Fundamentals
Figure 29 shows a typical application of the DHCP relay agent.
Figure 29 DHCP relay agent application
IP network
DHCP server
DHCP relay agent
DHCP client DHCP client
DHCP client DHCP client
The DHCP server and client interact with each other in the same way with or without a relay agent (see
the chapter “DHCP overview”).