Create The Dialing Plan File On The Provisioning Server - Nortel 1120E Administration Manual

50 Configure the provisioning server
Create the Dialing Plan file on the provisioning server
A dialing plan essentially describes the number and pattern of digits that
a user dials to reach a particular telephone number. Access codes, area
codes, specialized codes, and combinations of the number of digits dialed
are all part of a dialing plan.
The purpose of the dialing plan is so that the end user does not have to
press the send or # key to have the IP Phone 1120E with SIP Firmware
send the initial message to start the call.
Dialing a telephone number on an IP Phone that supports SIP can be
different than dialing a number from a traditional telephone. SIP signaling
is communicated through a SIP URI to get to the far end. For example,
you can key in the SIP address, jsmith@yourcompany.com to reach John
Smith. When the IP Phone 1120E with SIP Firmware receives this address,
the dialing plan is bypassed and the IP Phone 1120E simply uses the
SIP URI to send a SIP INVITE to jsmith@yourcompany.com (INVITE sip:
jsmith@yourcompany.com).
Entering a SIP URI address, however, is inconvenient for an IP Phone with
SIP Firmware unless a USB keyboard is attached. Also, the user must
explicitly press the send key (or use some method to indicate the end of the
URI) to indicate the completion of the SIP address. This is not something
that the user is accustomed to in a traditional PBX environment.
The alternative is to use a URI where numbers are used to reach the
far end. Using different access codes, the IP Phone with SIP Firmware
translates the digits entered into something that the server can understand
and remaps the number entered into different URIs. Some of the numbers
are mapped as intercom calls, some numbers are mapped as local Public
Switched Telephone Network (PSTN) calls, and some numbers are mapped
as public long-distant calls.
The issue is that until the IP Phone itself can determine the type of call, no
SIP INVITE message is sent. This is where the dialing plan comes into
effect. The call type is determined by the dialing plan. Based on the rules
defined in the dialing plan, once a match has been identified, the IP Phone
1120E with SIP Firmware sends the invite without the need to press the
send key. This behavior closely matches the traditional PBX operation.
The IP Phone 1120E with SIP Firmware design places no restriction in
the format of the SIP URI. The dialing plan is a scheme to match the user
experience with traditional PBX operation. It does not restrict the type of
URI that the user can use.
Copyright © 2008, Nortel Networks
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SIP Firmware Release 1.1 for IP Phone 1120E Administration
NN43112-300 02.03 Standard
27 May 2008