State-Transition Diagram For Dhcp Clients - Panasonic DP-1820P Service Manual

Several options have been defined so far. One particular option - the "DHCP message type" option - must
be included in every DHCP message. This option defines the "type" of the DHCP message.
Additional options may be allowed, required, or not allowed, depending on the DHCP message type.
INITIALIZE/
REBOOT
-/Send DHCPREQUES
REBOOTING
DHCPOFFER/
Discard
DHCPACK/
Record lease, set
timers T1, T2
T1 expires/
Send DHCPREQUEST
to leasing server
The client maintains two times, T1 and T2, that specify the times at which the client tries to extend its lease on its
network address. T1 is the time at which the client enters the RENEWING state and attempts to contact the server
that originally issued the client's network address. T2 is the time at which the client enters the REBINDING state and
attempts to contact any server. T1 MUST be earlier than T2, which, in turn, MUST be earlier than the time at which
the client's lease will expire.
To avoid the need for synchronized clocks, T1 and T2 are expressed in options as relative times.
For more detailed information, please refer to RFC2131 document available from the following URL:
http://www.ietf.org/rfc.html.
Ver. 1.2
DHCPACK
DHCPNAK/
(not accepted)/
Restart
Send DHCPDECLINE
DHCPNAK/
Discard offer
send DHCPREQUEST
REQUESTING
DHCPACK/
Record lease, set
/timers T1,T2
BOUND
DHCPREQUEST
to leasing server

State-transition diagram for DHCP clients

INITIALIZATION
-/Send DHCPDISCOVER
SELECTING
Select offer/
DHCPACK/
Record lease, set
/timers T1,T2
DHCPACK/
Record lease, set
timers T1, T2
T1 expires/
RENEWING
Send
453
DP-1520P/1820P/1820E
DHCPNAK, Lease expired/
Halt network
DHCPOFFER/
Collect replies
REBINDING
T2 expires/
Broadcast
DHCPREQUEST
DHCPNAK/
Halt network
SEP 2004