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MultiVoice Gateway for the MAX— User’s Guide Preliminary November 23, 1998 1-1

Introducing MultiVoice Gateway concepts

A brief overview

Traditionally, real-time voice information is sent over the Public Switched Telephone Network

(PSTN). Circuit-switched technology provides every call with dedicated bandwidth, usually

64Kbps. End-to-end calls are established on the basis of a sequence of dialed digits, and the

PSTN dedicates a physical path between callers. Because the telephone equipment establishes

the call path at the beginning of the call, the path can change between calls, but never while a

call is active.

Figure 1-1 illustrates an example of a PSTN network. Caller A dials Caller B’s phone number.

As Caller A dials the phone number, the network might route the call from Switch 1 to Switch

2 to Switch 3, which connects to Caller B. Once the PSTN establishes the call, communication

travels only through Switch 1, Switch 2, and Switch 3.

Figure 1-1. Example of call routing over circuit-switched PSTN

If Caller A dials Caller B again, the PSTN might establish the call by routing it from Switch 1

to Switch 4 to Switch 5 to Switch 3 before finally connecting Caller A to Caller B. Again, the

path can change between calls, but not during any specific call.

In contrast, an Internet Protocol (IP) network has a packet-switched architecture. Devices

transmit data in packets, and the path from end to end can vary within an established session.

A brief overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

What is MultiVoice for the MAX?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

MultiVoice applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8

Caller A

Caller B

Switch 5

Switch 4

Switch 1

Switch 2

Switch 3

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Ascend MultiVoice Gateway Guide de l'utilisateur Page 25