H3C S3600 Series User Manual

Operation Manual – Management VLAN
H3C S3600 Series Ethernet Switches-Release 1510 Chapter 2
DHCP/BOOTP Client Configuration
2-3
packet contains the IP address carried in the DHCP_Offer packet the DHCP client
receives.
z Acknowledgement. Upon receiving the DHCP_Request packet, the DHCP server
that owns the IP address carried in the DHCP_Request sends a DHCP_ACK
packet to the DHCP client. The packet contains the IP address offered and other
configuration information. The DHCP client binds TCP/IP protocol components to
its MAC address after receiving the packet.
IP addresses offered by other DHCP servers (if any) through DHCP_Offer packets but
not selected by the DHCP client are still available for other clients.
2) The DHCP client accesses the network for the second and the followed time
In this case, the DHCP client establishes connections with the DHCP server through
the following steps.
z After accessing the network successfully for the first time, the DHCP client can
access the network again by broadcasting a DHCP_Request packet that contains
the IP address assigned to it last time instead of a DHCP_Discover packet.
z Upon receiving the DHCP_Request packet and, when the IP address applied by
the client is available, the DHCP server that owns the IP address responds with a
DHCP_ACK packet to enable the DHCP client to use the IP address again.
z If the IP address is not available (for example, it is assigned to another DHCP
client), the DHCP server responds with a DHCP_NAK packet, which enables the
DHCP client to request for a new IP address by sending a DHCP_Discover packet
once again.
3) The DHCP client extends the lease of an IP address
IP addresses assigned dynamically are only valid for a specified period of time and the
DHCP servers reclaim their assigned IP addresses at the expiration of these periods.
Therefore, a DHCP client need to extend the lease period if it is to use a dynamically
assigned IP address for a period longer than allowed.
By default, a DHCP client updates its IP address lease automatically by sending
DHCP_Request packets to the DHCP server when half of the lease period expires. The
DHCP server, in turn, responds with a DHCP_ACK packet to notify the DHCP client of
the new lease if the IP address is still available. An S3600 series switch operating as a
DHCP support this lease auto-update process.
2.2 Introduction to BOOTP Client
A BOOTP client can request the server for an IP address through BOOTP. It goes
through the following two phases to apply for an IP address.
z Sending a BOOTP request packet to the server
z Processing the BOOTP response packet received from the server
To obtain an IP address through BOOTP, a BOOTP client first sends a BOOTP request
packet to the server. Upon receiving the request packet, the server returns a BOOTP

H3C S3600 Series Specifications

General

Brand	H3C
Model	S3600 Series
Category	Switch
Language	English