Voice over ATM Switched Virtual
Circuits on the Cisco MC3810
This document describes voice over Asynchronous Transfer Mode (VoATM) switched virtual
circuits (SVCs) for the Cisco MC3810 multiservice access concentrator.
This document includes the following sections:
Feature Overview, page 1
Troubleshooting Voice over ATM SVCs, page 16
Monitoring and Maintaining Voice over ATM SVCs, page 19
Configuration Examples, page 20
Command Reference, page 22
Glossary, page 30
VoATM SVCs allow the Cisco MC3810 to transfer voice data dynamically and as needed-without
tying up the resources required for static, manually provisioned permanent virtual circuits (PVCs).
An SVC connection is initiated for each call, and each request includes bandwidth and
quality-of-service (QoS) information required for the connection. SVCs are ideal for networks that
are highly interconnected, where scalability is essential, and in situations where traffic is sporadic.
In addition, service providers often offer more advantageous, usage-based pricing options for SVCs.
VoATM using SVCs on the Cisco MC3810 includes all of the voice features that the Cisco MC3810
supports for PVCs and for Frame Relay transport. Like other Cisco voice implementations, VoATM
using SVCs is based on dial peers and uses ATM Adaptation Layer 5 (AAL5).
ATM SVC service operates much like X.25 SVC service, although ATM allows much higher
throughput. It requires a signaling protocol between a router or a multiservice access concentrator
and an ATM switch. The ATM signaling software provides a method of dynamically establishing,
maintaining, and clearing ATM connections at the User-Network Interface (UNI). In UNI, the router
serves as the user and the ATM switch is considered the network. The router does not perform
call-level routing. Instead, the ATM switch does the ATM call routing, and the router directs packets
through the resulting circuit.