3Com SuperStack 3 NBX, Administrator'S Manual

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Dial Plan Concepts and Overview 29
Call Process Flow The dial plan configuration file is a key component of inbound and
outbound call processing. The dial plan tables in the configuration file
process
incoming calls in this order:
1 Incoming Dial Plan Table
2 Pretranslator Table
The dial plan tables process outgoing calls in this order:
1 Internal Dial Plan Table
2 Least Cost Routing Table
After pretranslation (if performed), the final translation process routes the
call to the destination.
Inbound and
Outbound Call
Processing
The system routes all inbound and outbound calls through the dial plan.
Inbound Call Processing
The system processes inbound calls using the Incoming table. The system
can also use pretranslators to perform digit manipulations on incoming
calls before it uses the Incoming table.
Each pretranslator operation performs a digit manipulation operation on
the dialed digits. For incoming calls, if the DID/DDI range matches the
internal extensions, the dial plan requires no pretranslator. However, you
can use pretranslators to map nonmatching dialed numbers on an
incoming DID/DDI channel to desired internal extensions. See the
example in Customer Requirement 1 in “Sample Solutions Using Dial Plan
Configuration File Commands” later in this chapter.
Outbound Call Processing
The system processes outbound calls using the Internal dial plan table or
the Least Cost Routing table.
You can add entries to the Internal dial plan table to match the system to
your service. See Customer Requirement 2 in “Sample Solutions Using
Dial Plan Configuration File Commands” later in this chapter.
If you have entries in both the Least Cost table and the Internal table for
the same purpose, the behavior of the dial plan can be confusing. 3Com
recommends that you accomplish least cost routing using Internal Table
entries. For more information, see
TimedRoute Create , TimedRouteEntry
Create , and TimedRouteOperation Create later in this chapter.