AT&T 7400 series Network Router User Manual


 
2-6 COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW
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switch for processing.
DIMENSION, System 85, and Generic 2 Multipremises Package
The set of software capabilities that enable a DIMENSION, System 85, or Generic 2 communications system
to function as a node in a MS/T network are provided through the Multipremises package.
The Multipremises package uses extension number steering to route a call through the network. With
extension number steering, the caller dials the destination extension number. The switch matches the
extension number to a dial access code. It sends calls to terminals on other switches over the trunk group
that the dial access code designates.
In addition to extension number steering, the DIMENSION, System 85, and Generic 2 Multipremises package
includes the Extended Trunk Access (ETA) feature. ETA is a capability used only in a satellite or tributary
switch. With ETA, instead of entering all network extensions and their switch locations on the satellite, the
administrator enters only satellite or tributary extensions there. Calls originating on the satellite to
extensions not on the satellite database are sent to the main for processing. For ETA to function properly,
the trunk group that connects the satellite or tributary switch to the main switch must be identified through
administration. In addition, the satellite flag must be set for ETA operation.
Electronic Tandem Network Software — The PNA and ETN (Standard Network) Packages
The Private Network Access (PNA) package enables a System 75 or Generic 1 communications system to
perform as a tandem in an electronic tandem network. Similarly, the ETN (Standard Network) package
allows a DIMENSION, System 85, or Generic 2 communications system to perform in the same capacity.
The capabilities offered by both the PNA and ETN (Standard Network) packages are provided through
Automatic Alternate Routing (AAR). AAR is a feature that ensures least-cost routing for private network
calls. (See Network Call Processing later in this chapter for more details.)
System 75 and Generic 1 PNA Package
For a System 75 or Generic 1 communications system to function as a tandem in an ETN, the PNA package
must be activated there. The PNA package provides the same features as the UDP package, plus it provides
access to AAR through feature-access-code dialing.
DIMENSION, System 85, and Generic 2 ETN (Standard Network) Package
The ETN (Standard Network) package is totally unrelated to the Multipremises software that is used to
enable a DIMENSION, System 85, or Generic 2 communications system as a node in a MS/T network. With
the ETN (Standard Network) package, to reach the destination terminal the caller may dial either the
extension number (which points either to an RNX or to a node number), or the AAR feature access code
(usually an 8), followed by the RNX and the extension number.
When a System 85 or Generic 2 communications system is administered so that the caller may dial the
extension number only, either of two dialing conventions are in operation: