Cisco Systems (VISM) Telephony Applications Using VISM

CHAPTER

2-1

Cisco VISM Installation and Configuration Guide

Release 3.0, Part Number OL-2521-01 Rev. D0, June 2004

Telephony Applications Using VISM

This chapter describes the VISM card and the ways it is used in telephony applications to transport

traditional TDM voice traffic as digitized voice traffic over ATM networks. The following topics are

discussed:

•“Tandem Switch Offloading” section on page2-1

•“Multiservice Access” section on page2-3

•“AAL2 Trunking” section on page 2-3

Figure 2-1 shows VISM used to offload a Class 4 tandem switch by transporting a portion of the voice

traffic across an ATM network instead of the Public Switched Telephone Network (PSTN). VISM acts

as the voice gateway in this application. Use VISM in the VoIP switching or switched AAL2 PVC

operating mode to enable this application.

Figure2-1 VISM Used in a Tandem Switch Offloading Application

MGX 8850

with VISM

Call Agent

Class 4

Switch

IP Network

PSTN Network

53233

Central

Office

SS7 Network