Nortel BCM50 Configuration Manual page 344

344 Chapter 38 Private networking: PRI Call-by-Call services
The total required is thus 28 lines. If the BCM systems were using T1 trunks, then two T1 spans
would be required at each office. Note that the total of 28 lines represents the worst case value for
line usage. In reality, the total number of lines in use at any one time will generally be less than 28.
For example, during periods of peak incoming call traffic, the demand for outgoing lines will be
low.
With PRI Call-by-Call services, it is not necessary to configure a fixed allocation of trunks. Each
of the 23 lines on the PRI can be used for DID, private TIE, or outgoing public calls. This
consolidation means that it may be possible for each office to use a single PRI span, rather than
two T1 spans. With PRI Call-by-Call services, the only limitation is that there are no more than
23 calls in progress at any one time.
The dialing plan at each BCM site is configured to determine the call type based on the digits
dialed by the user. If a user in Toronto wishes to dial a colleague in New York, they dial the
four-digit private DN (such as 6221). The dialing plan recognizes this as a private network DN,
and routes the call using TIE service with a private dialing plan.
Incoming TIE calls are routed to telephones based on the digits received by the network, which in
this case will be the four-digit private DN.
If a user in either location wishes to dial an external number, they dial 9, followed by the number
(such as 9-555-1212). The dialing plan recognizes this as a public DN, and routes the call using
Public service.
Incoming DID calls will be routed to telephones, based on the trailing portion of the digits
received by the network. For example, if a public network user dials an employee in the Toronto
office, the network delivers digits 4167632221. The BCM routes the call using the last four digits,
2221, to the BCM50.
Refer to Table 73
Table 73 PRI Call-by-Call services routing information (Sheet 1 of 2)
Parameter
Hardware
DTM
Protocol
Trunk/Line Data
Line 125
Private/Public Received # 2221
Line Access
DN 2221
Line pool access
Routing Services
Route
External #
Use
Service type
NN40020-603 NN40020-603
for a description of the settings required for this type of routing service.
Home System Settings
PRI
NI-2
Target line
L125:Ring only
Line pool BlocA
Private Network
New York:
001
No number
Pool BlocA
TIE
Public network
Public network
002
No number
Pool BlocA
Public