Nortel Networks NN43001-504 - Manual (Page 187)

DHCP options 187
DHCP support for handsets that emulate the IP Phone 2004
DHCP support in the IP Phone 2004 terminal requires a Class Identifier
option with each DHCP Discovery and Request message. Additionally,
the IP Phone 2004 checks for either a Vendor Specific option message
with a specific, unique to Nortel IP Phone 2004 encapsulated subtype, or a
site-specific DHCP option. In either case, a Nortel IP Phone 2004 specific
option must be returned by the IP Phone 2004 aware DHCP server in all
Offer and Ack messages. The IP Phone 2004 uses the information returned
in this option to configure itself for proper operation. This configuration
includes binding a new IP address, netmask and gateway (for the local IP
stack) as well as configuring Server 1 (minimum) and, optionally Server 2.
By default, Server 1 is always assumed to be the primary server after a
DHCP session.
The IP Phone 2004 does not accept any Offers or Acks that do not contain
all of the following options:
• a Router option
The IP Phone 2004 requires a default router to function.
• a Subnet Mask option
• a Vendor Specific option
OR
a Site Specific option
The initial DHCP implementation required only the Vendor Specific
encapsulated suboption. In interop testing with WinNT (up to SR4), it
was discovered that WinNT does not properly adhere to RFC 1541.
As a result, it is not possible to use this option. The implementation
was changed to add support for either Vendor Specific subops or Site
Specific options. This new extension is tested and verified to work with
WinNT.
The site-specific options are all DHCP options between 128 (0x80)
and 254 (0xFE). These options are reserved for site specific use by
the DHCP RFCs.
Format of the IP Phone 2004 Terminal DHCP Class Identifier field
All IP Phone 2004 terminals fill in the Class ID field of the DHCP Discovery
and Request messages with Nortel-i2004-A:
• ASCII-encoded, NULL (0x00) terminated
• unique to Nortel IP Phone 2004
• –A uniquely identifies this version
Nortel Communication Server 1000
WLAN IP Telephony Installation and Commissioning
NN43001-504 01.02 Standard
Release 5.0 15 June 2007
Copyright © 2004-2007, Nortel Networks
.