4-8
T1/E1 Digital Voice Port Adapter Installation and Configuration
OL-3592-02
Chapter 4 Configuring the PA-VXA, PA-VXB, and PA-VXC
Configuring Voice over IP
•
Custom queuing
•
Weighted fair queuing
See the
“Configure IP Networks for Real-Time Voice Traffic” section on page 4-9
for information about
how to select and configure the appropriate QoS tools to optimize voice traffic on your network.
Step 2
(Optional) If you plan to run VoIP over Frame Relay, you need to take certain factors into consideration
when configuring VoIP for it to run smoothly over Frame Relay. For example, a public Frame Relay
cloud provides no guarantees for QoS. See the
“Configuring Voice over Frame Relay” section on
for information about deploying VoIP over Frame Relay.
Step 3
Use the num-exp command to configure number expansion if your telephone network is configured so
that you can reach a destination by dialing only a portion (an extension number) of the full E.164
telephone number. See the
“Configure Number Expansion” section on page 4-14
for information about
number expansion.
Step 4
Use the dial-peer voice command to define dial peers and switch to the dial-peer configuration mode.
Each dial peer defines the characteristics associated with a call leg. A call leg is a discrete segment of a
call connection that lies between two points in the connection. An end-to-end call comprises four call
legs, two from the perspective of the source router, and two from the perspective of the destination router.
Dial peers are used to apply attributes to call legs and to identify call origin and destination. There are
two different kinds of dial peers:
•
POTS—Dial peer describing the characteristics of a traditional telephony network connection.
POTS peers point to a particular voice port on a voice network device. To minimally configure a
POTS dial peer, you need to configure the following two characteristics: associated telephone
number and logical interface. Use the destination-pattern command to associate a telephone
number with a POTS peer. Use the port command to associate a specific logical interface with a
POTS peer. In addition, you can specify direct inward dialing for a POTS peer by using the
direct-inward-dial command.
•
VoIP—Dial peer describing the characteristics of a packet network connection; in the case of VoIP,
this is an IP network. VoIP peers point to specific VoIP devices. To minimally configure a VoIP peer,
you need to configure the following two characteristics: associated destination telephone number
and a destination IP address. Use the destination-pattern command to define the destination
telephone number associated with a VoIP peer. Use the session-target command to specify a
destination IP address for a VoIP peer.
In addition, you can use VoIP peers to define characteristics such as IP precedence, additional QoS
parameters (when RSVP is configured), codec, and voice activation detection (VAD). Use the ip
precedence command to define IP precedence. If you have configured RSVP, use either the req-qos or
acc-qos command to configure QoS parameters. Use the codec command to configure specific voice
coder rates. Use the vad command to disable voice activation detection and the transmission of silence
packets.
See the
“Configure Dial Peers” section on page 4-16
and the
“Optimize Dial Peer and Network Interface
Configurations” section on page 4-29
for additional information about configuring dial peers and
dial-peer characteristics.
Step 5
You need to configure your router to support voice ports. In general, voice-port commands define the
characteristics associated with a particular voice-port signaling type. Voice ports on the
Cisco 7200 series routers, Cisco 7200 VXR routers, Cisco 7301 router, Cisco 7401ASR routers, and
Cisco 7500 series routers support three basic voice signaling types:
•
FXO—Foreign Exchange Office interface
•
FXS—Foreign Exchange Station interface
•
E&M—“RecEive and TransMit” interface or the “Ear and Mouth” interface
