Operation Manual – Management VLAN
Quidway S3100 Series Ethernet Switches
Chapter 2 DHCP/BOOTP Client Configuration
Huawei Technologies Proprietary
2-2
DHCP Client
DHCP Server
DHCP Client
DHCP Client
DHCP Client
DHCP Server
DHCP_D
iscover
DHCP_R
equest
DHC
P_Of
fer
DHC
P_AC
K
DHCP_R
enew
DHC
P_AC
K
DHCP Client
DHCP Client
DHCP Server
DHCP Server
DHCP Client
DHCP Client
DHCP Client
DHCP Client
DHCP Client
DHCP Client
DHCP Server
DHCP Server
DHCP Server
DHCP Server
DHCP Server
DHCP_D
iscover
DHCP_R
equest
DHC
P_Of
fer
DHC
P_AC
K
DHCP_R
enew
DHC
P_AC
K
Figure 2-2
Interaction between a DHCP client and the DHCP server
To obtain valid dynamic IP addresses, a DHCP client exchanges different information
with the DHCP server in different phases. Usually, the following three modes are
involved:
1)
The DHCP client accesses the network for the first time
In this case, the DHCP client goes through the following four phases to establish
connections with the DHCP server.
z
Discovery. The DHCP client discovers a DHCP server by broadcasting
DHCP_Discover packets in the network. Only the DHCP servers respond to this
type of packets.
z
Offer. Upon receiving DHCP_Discover packets, a DHCP server select an
available IP address from an address pool and sends a DHCP_Offer packet that
carries the selected IP address and other configuration information to the DHCP
client. The DHCP client only accepts the first-arrived DHCP_Offer packet (if there
are many DHCP servers), and broadcasts a DHCP_Request packet to each
DHCP server. The packet contains the IP address carried by the DHCP_Offer
packet.