Overview Of Dhcp Client; Brief Introduction - Huawei Quidway S3500 Series Operation Manual

Operation Manual - Network Protocol
Quidway S3500 Series Ethernet Switches
Note:
This chapter only applies to S3552G, S3552P, S3528G, S3528P, S3552F, S3526E,
S3526E FM, S3526E FS and S3526C in S3500 series switches.

3.5 Overview of DHCP Client

3.5.1 Brief Introduction

With expansion of network size and complication of network structure, network
configuration becomes more and more complex. It is often the case that computers
change physical positions frequently (portable computers and wireless networks for
example) and that computers exceed the IP addresses available. Dynamic host
configuration protocol (DHCP) has been developed right for this situation. DHCP is in
client/server structure, with DHCP client dynamic requesting configuration information,
while DHCP server returning configuration information base on the specific policies.
A typical DHCP application often contains a DHCP server and several clients (desktop
and laptop PCs). See the following figure.
DHCP Client
DHCP Client
Figure 3-1 Typical DHCP application
To obtain valid dynamic IP addresses, DHCP client exchanges different types of
information with the server at different stages. One of the following three situations may
occur:
1) DHCP client logs into the network for the first time
When DHCP client logs into the network for the first time, its communication with the
DHCP server includes these four stages:
Discover stage, the stage when the DHCP client looks for the DHCP server. The
client broadcasts the DHCP_Discover message and only the DHCP server can
respond.
DHCP Client
DHCP Server
LAN
DHCP Client
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