Nortel IP telephones supports two forms of DHCP configuration: full and partial. If partial DHCP
is selected, the user must manually enter the primary and secondary Business Communications
Manager address/action/retry count. The IP telephone then configures a IP address/netmask and
default IP gateway via DHCP. If full DHCP is selected, the IP telephone configures all parameters
via DHCP.
Note: If partial DHCP is selected, the DHCP server does not need to send the vendor-specific or
site-specific information outlined below. The information below pertains to Full DHCP only. In
the case of partial DHCP, the IP telephone requires only the Router option and Subnet Mask
option to configure (along with IP address and lease time).
Full DHCP support in the IP terminals requires sending a Class Identifier option with each DHCP
Discovery and Request message. Additionally, the IP telephone checks for either a vendor-specific
option message with a specific, unique to Nortel IP telephones, encapsulated sub-type OR a
site-specific DHCP option. In either case, a Nortel IP telephone-specific option must be returned
by the IP telephone-aware DHCP server in all Offer and Ack messages. The IP telephone will use
the information returned in this option to configure itself for proper operation. This includes
binding a new IP address, netmask and gateway (for 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 telephone will not accept any Offers/Acks if they do not contain:
• a Router option (the IP telephone needs a default router to function) AND
• a Subnet Mask option AND
• an S1 Server Address and Port
• The Nortel IP telephones require the scope value 128 to be configured on the DHCP server as
follows:
Format example:
Nortel-i2004-A,iii.jjj.kkk.lll

pppp,aaa,rrr;iii.jjj.kkk.lll

ppp,aaa,rrr.
where,
Nortel-i2004-A uniquely identifies this as the Nortel option
Additionally, the -A signifies this version of this specification. Future enhancements could use
-B, for example.
ASCII , is used to separate fields
ASCII ; is used to separate Primary from Secondary Business Communications Manager
information
ASCII . is used to signal end of structure
iii.jjj.kkk.lll

pppp identifies IP

ort for server (ASCII encoded decimal)
aaa identifies Action for server (ASCII encoded decimal, range 0..255)
rrr identifies retry count for Business Communications manager (ASCII encoded decimal,
range 0..255). This string may be NULL terminated, although the NULL is not required for parsing.
-SD-