H3C S3600 Series User Manual

Operation Manual – DHCP
H3C S3600 Series Ethernet Switches-Release 1510 Chapter 3
DHCP Relay Configuration
3-1
Chapter 3 DHCP Relay Configuration
3.1 Introduction to DHCP Relay
3.1.1 Usage of DHCP Relay
Since the packets are broadcasted in the process of obtaining IP addresses, DHCP is
only applicable to the situation that DHCP clients and DHCP servers are in the same
network segment, that is, you need to deploy at least one DHCP server for each
network segment, which is far from economical.
DHCP Relay is designed to address this problem. It enables DHCP clients in a subnet
to communicate with the DHCP server in another subnet so that the DHCP clients can
obtain IP addresses. In this case, the DHCP clients in multiple networks can use the
same DHCP server, which can decrease your cost and provide a centralized
administration.
3.1.2 DHCP Relay Fundamentals
Figure 3-1 illustrates a typical DHCP relay application.
Ethernet
DHCP
client
DHCP clientDHCP client
DHCP client
Switch ( DHCP rel
Internet
ay
)
DHCP server
Ethernet
DHCP
client
DHCP clientDHCP client
DHCP client
Internet
)
Ethernet
DHCP
client
DHCP clientDHCP client
DHCP client
Switch ( DHCP rel
Internet
ay
)
DHCP server
Ethernet
DHCP
client
DHCP clientDHCP client
DHCP client
Internet
)
Ethernet
DHCP
client
DHCP clientDHCP client
DHCP client
Switch ( DHCP rel
Internet
ay
)
DHCP server
Ethernet Internet
DHCP
client
Ethernet
DHCP
client
DHCP clientDHCP client
DHCP client
Switch ( DHCP rel
Internet
ay
)
DHCP server
Ethernet
DHCP
client
DHCP clientDHCP client
DHCP client
Internet
)
Figure 3-1 Typical DHCP relay application
DHCP relays can transparently transmit broadcast packets of DHCP clients or servers
to the DHCP servers or clients in other network segments.
In the process of dynamic IP address assignment through the DHCP relay, the DHCP
client and DHCP server interoperate with each other in a similar way as they do without
the DHCP relay. The following sections only describe the forwarding process of the
DHCP relay. For the interaction process of the packets, see section
1.2.2 “Obtaining IP
Addresses Dynamically
”.
1) The DHCP client broadcasts the DHCP-DISCOVER packet.

H3C S3600 Series Specifications

General

Brand	H3C
Model	S3600 Series
Category	Switch
Language	English