Dhcp Messages; Dhcp Message Format - Nortel Meridian ITG Line 2.0 Description, Installation And Operation Manual

DHCP messages

There are seven different DHCP messages. Each message relates certain
information between the client and server (see Table 2).
Table 46
DHCP message types
DHCP Message Types
DHCPDISCOVER
DHCPOFFER
DHCPREQUEST
DHCPAK
DHCPNAK
DHCPDECLINE
DHCPRELEASE

DHCP Message Format

The DHCP message format shown in Figure 41 is common to all DHCP
messages. Each message is made of 15 fields, 14 fixed-length fields and one
variable length field. The fixed-length fields must be the specified number of
bytes as indicated in the brackets. If there is not enough data, or there is no
data at all, zeros are used to fill in the extra spaces.
The Options field is the only field with a variable length. It is optional, but
very important as it transports additional network configuration parameters.
The DHCP options are the actual subfields that are used in this project.
ITG Line 2.0/i2004 Internet Telephone Description, Installation, and Operation
Description
Initiates a client request to all servers.
Offer from server following client request.
Request a particular server for services.
Notify client that requested parameters could
be met.
Notify client that requested parameters could
not be met.
Notify server that offer is unsatisfactory and
will not be accepted.
Notify server that IP address is no longer
needed.
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