User`s guide

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