Cisco Systems MGX 8230 manual Voice Service The Vism, Vism Documentation

Chapter 2 Module and Service Descriptions

Frame Relay Service Modules

Voice Service: The VISM

The Voice Interworking Service Module (VISM) is a front and back card set designed to transport digitized voice signals across a packet network. This provides an interface or gateway between conventional voice TDM networks and networks based upon packet switching technology.

There are two types of VISM front cards:

•MGX-VISM-8T1: supports up to eight T1 lines carrying digitized voice

•MGX-VISM-8E1: supports up to eight E1 lines carrying digitized voice.

VISM Documentation

Installation, configuration and support for the VISM services are not included in this manual. For more information on the VISM, refer to the following Cisco Systems publications:

•For information on VISM features and configuration, refer to Voice Interworking Service Module Installation and Configuration.

•For up to date information on VISM version support and features, refer to the Software Release Notes Cisco WAN MGX 8850, 8230, and 8250 Software.

Summary of Features Supported with VISM 2.0.1

The following features are supported with VISM 2.0.1 on the MGX 8230.

Note The MGX 8230 supports VISM 2.0.1 and higher. All of the features available in VISM 1.5.5 are also available in version 2.0.1

VoIP using RTP (RFC 1889)

VISMR1.5 supports standards-based VoIP using RTP (RFC1889) and RTCP protocols. This allows VISM to interwork with other VoIP Gateways.

VoAAL2 (With sub-cell multiplexing) PVC

The VISM supports standards-compliant AAL2 adaptation for the transport of voice over an ATM infrastructure. AAL2 trunking mode is supported.

Codec Support

G.711 PCM (A-law, Mu-law), G.726, G.729a/b

Eight T1/E1 Interfaces

The VISM supports eight T1 or eight E1 interfaces when G.711 PCM coding is used. For higher complexity coders such as G.726-32K and G.729a-8K, the density drops to six T1 or five E1 interfaces (max 145 channels).

1:N Redundancy

1:N redundancy using SRM.

	Cisco MGX 8230 Edge Concentrator Installation and Configuration
Release 1.1.31, Part Number 78-11215-03 Rev. B0, May 2001		2-55