User guide

Chapter 1. Router Concepts 19
Configuring Your Telephony Services
Router models are available to support telephony services over both ATM and Frame Relay networks. For
telephony over ATM, the VPI/VCI is automatically set (to 0*39 for most routers). For telephony over Frame
Relay, the DLCI is automatically set to 22. The value must match your service providerÕs value. You can change
the value if necessary (see Troubleshooting Telephony Services, page 288).
The phone number for each port is set by your voice service provider.
The phone dial tone is provided by the Class 5 switch via the voice gateway at your regional switching center
(RSC). All voice features of the switch are passed through to the phone set. The router supports the calling
services that you subscribe to from your service provider, such as call forwarding, caller ID, messaging, etc.
The bandwidth required for a voice call depends on whether PCM or ADPCM encoding is used. With PCM, each
voice call takes about 80 Kb of bandwidth (64 Kb plus overhead) when the phone goes off hook. With ADPCM,
only about 40 Kb is used (32 Kb plus overhead).
Configuration for voice and data routing can be performed using the Web-based Easy Setup configuration
program.
You can use the Port Monitor GUI program to see the voice PVC and the last event message. To see LMI
statistics for a frame relay router, use the frame stats command (page 150). To see AAL2 statistics for the voice
gateway, use the voice l2stats command (Jetstream gateway only). For other commands to monitor telephony
services, see Trouble-Shooting Telephony Services (page 288).
Phone
system
LAN
DSLAM
ATM/Frame
Network
Router
Voice
Gate-
way
Class 5
Switch
Internet
PSTN
Voice
over
DSL
Router
DSL
Line
Phone lines
Ethernet