Nortel BCM 3.7, Manual

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Private networking with DPNSS 559
Programming Operations Guide
Loop avoidance
Errors in the configuration of a network may make it possible for a call to be misrouted, and arrive
at a PBX system through which it has already passed. This would continue, causing a loop which
would eventually use up all of the available channels. The Loop Avoidance service permits
counting of DPNSS 1 transit PBXs and rejecting a call when the count exceeds a predetermined
limit.
Programming loop avoidance
To set Loop avoidance during hardware configuration:
1 Click the keys beside Resources, Media Bay Modules , Bus 02 - 07 , Modules on Bus.
2
Select Module 1.
3
Choose Module type DPNSS .
4
Type a value (0-25) in the Maximum transits box.
The default value is 25.
Private networking with DPNSS
(International only)
DPNSS supports the Universal Dialing Plan (UDP), an international standard for sending and
receiving private numbers over networks. The UDP requires that a dialing number includes the
following:
• a Private Access Code, programmed into the system as part of the destination code table to
prevent conflicts with the internal numbering system. (
Access Codes )
• a Home Location Code (HLC) assigned to each PBX system, and configured as part of the
destination code (a maximum of seven digits). For each HLC, a routing code must be
programmed in the system. (
Dialing plan, UDP, Location code )
• a Directory Number (DNs) assigned to each extension as a line appearance. The DN appears
as the last string segment in a dialed number. In the number 244-1111, 1111 is the DN.
A typical Private Number, using a private access code and dialed from another site on the network,
appears below.
In this networking example, a private network is formed when several systems are connected
through a Meridian M1 and a terminating Business Communications Manager system. Each site
has its own HLC and a range of DNs. The figure below illustrates this example.
Private Access Code + Home Location Code + Directory Number = Calling Party Number
6 + 848 + 2222 = 6-848-2222