Cisco PA-VXA Series Installation And Configuration Manual page 81

Chapter 4 Configuring the PA-VXA, PA-VXB, and PA-VXC
RSVP reservations are only one-way. If you configure RSVP, the VoIP dial peers on both ends of the
Note
connection must be configured for RSVP.
Configure Codec and VAD for Dial Peers
Coder-decoder (codec) and voice activity detection (VAD) for a dial peer determine how much
bandwidth the voice session uses. Typically, codec is used to transform analog signals into a digital bit
stream and digital signals back into analog signals—in this case, it specifies the voice coder rate of
speech for a dial peer. VAD is used to disable the transmission of silence packets.
Configure Codec for a VoIP Dial Peer
To specify a voice coder rate for a selected VoIP peer, use the following commands, initially beginning
in global configuration mode:
Command
Step 1
dial-peer voice number voip
Step 2
codec [g711alaw | g711ulaw |
g729r8]
The default for the codec command is g729r8; normally the default configuration for this command is
the most desirable. If, however, you are operating on a high-bandwidth network and voice quality is of
the highest importance, you should configure the codec command for g711alaw or g711ulaw. Using
these values results in better voice quality, but it also requires higher bandwidth requirements for voice.
For example, to specify a codec rate of G.711a-law for VoIP dial peer 108, enter the following:
dial-peer voice 108 voip
destination-pattern +1408528
codec g711alaw
session target ipv4:10.0.0.8
Configure VAD for a VoIP Dial Peer
To disable the transmission of silence packets for a selected VoIP peer, use the following commands,
beginning in global configuration mode:
Command
Step 1 dial-peer voice number voip
Step 2 vad
The default for the vad command is enabled; normally the default configuration for this command is the
most desirable. If you are operating on a high-bandwidth network and voice quality is of the highest
importance, you should disable vad. Using this value will result in better voice quality, but it will also
require higher bandwidth requirements for voice.
OL-3592-02
Purpose
Enter the dial-peer configuration mode to configure a VoIP peer.
Specify the desired voice coder rate of speech.
Purpose
Enter the dial-peer configuration mode to configure a VoIP peer.
Disable the transmission of silence packets (enabling VAD).
T1/E1 Digital Voice Port Adapter Installation and Configuration
Configuring Voice over IP
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