North American Dialing Plan - Nortel 1000 Fundamentals

66 System description
For example, Meridian 1/CS 1000M switch B node B1 has two entries for
NPA 408 and 4085, which point to nodes A1 and A2 of Meridian 1/CS 1000M
switch A, respectively. Calls from B1 with dialed digits 408-5xx-xxxx are
routed to the IP Trunk 3.01 (and later) node A1 while all other 408-xxx-xxxx
calls are routed to IP Trunk 3.01 (and later) node A2.

North American dialing plan

The North American dialing plan is used to make public network calls
through the private IP network. However, calls are not directly routed to the
Central Office (CO) through the LAN connection. Instead, a tandem switch
with voice trunk connections, including T1 ISDN PRI, serves as the gateway
to route voice calls coming through the LAN to the voice trunk.
Figure 20 "North American dialing plan call flow" (page 66)
placing a public call, through the private LAN, by dialing 1-415-456-1234 or
566-1234. The IP trunk card with IP address 47.82.32.124 searches for the
Numbering Plan Area (NPA) or Local Exchange Code (NXX) tables with the
matched NPA or NXX entries. When an entry is found, the corresponding
IP address is used to send H.323 call setup messages to the gateway (a
Meridian 1/CS 1000M with an IP address of 47.82.32.123), which routes the
call to the PSTN through a regular CO or DID trunk.
The translation table is expanded to allow extended, three-to six-digit NPA
codes. For example, DNs, such as 1-415-456-XXXX and 1-415-940-XXXX,
can have different destination IP addresses.
Figure 20
North American dialing plan call flow
Copyright © 2007, Nortel Networks
.
Nortel Communication Server 1000
IP Trunk Fundamentals
NN43001-563 02.01 Standard
Release 5.5 21 December 2007
shows DN 7000