H3C Technologies H3C WX6000 Series Access Controllers - Manual (Page 211)

26-16
Figure 26-14 DHCP relay agent application
IP network
DHCP server
DHCP relay agent
DHCP client DHCP client
DHCP client DHCP client
No matter whether a relay agent exists or not, the DHCP server and client interact with each other in a
similar way (see section Dynamic IP address allocation process ). The following describes the
forwarding process on the DHCP relay agent.
Figure 26-15 DHCP relay agent work process
As shown in Figure 26-15 , the DHCP relay agent works as follows:
1) After receiving a DHCP-DISCOVER or DHCP-REQUEST broadcast message from a DHCP client,
the DHCP relay agent fills the giaddr field of the message with its IP address and forwards the
message to the designated DHCP server in unicast mode.
2) Based on the giaddr field, the DHCP server returns an IP address and other configuration
parameters to the relay agent, which conveys them to the client.
DHCP Relay Agent Configuration Task List
Complete the following tasks to configure the DHCP relay agent:
Task Remarks
Enabling DHCP and
Configuring Advanced
Parameters for the DHCP
Relay Agent Required
Enable DHCP globally and configure advanced DHCP parameters.
By default, global DHCP is disabled.