3Com Router 3031, Command Reference Manual

Page: 439 / 838

DHCP Relay Configuration Commands 439
[3Com-Ethernet0/0/0] ip relay address 202.38.1.2
[3Com-Ethernet0/0/0] ip relay address 202.38.1.3
ip relay address cycle Syntax
ip relay address cycle
undo ip relay address cycle
View
System view
Parameter
None
Description
Using the ip relay address cycle command, you can adopt the polling approach to
relay packets, ensuring that different clients use different DHCP servers and the
same clients use the same DHCP server so long as it is possible. Using the undo ip
relay address cycle command, you can adopt the broadcast approach to relay
packets so as to broadcast client requests to all the DHCP servers.
By default, the broadcast approach is adopted.
Suppose that there are three clients, i.e., A, B, and C, and the DHCP server has
been configured with three relay addresses, i.e., S1, S2, and S3. If the polling
approach is adopted to relay packets, A, B, and C will respectively use the relay
addresses S1, S2, and S3. If A is shut down and restarted again, it will continue to
use S1. But if a client other than these three clients started, it will use S1. Thus, the
relay addresses will be used cyclically.
For the related command, see ip relay address.
Example
Adopt the polling approach to relay.
[3Com] ip relay address cycle
ip relay address
interface
Syntax
ip relay address ip-address [ interface ethernet-subinterface-range | all ]
undo ip relay address { ip-address | all } { interface ethernet-subinterface-range | all
}
View
System view
Parameter
■
ip-address: IP address of the DHCP server.
■
ethernet-subinterface-range: Includes all the subinterfaces whose interface
number lies between two subinterface numbers (including these two
subinterfaces) by inserting the keyword “to” between these two interface
numbers.