Altigen AltiContact Manager Version 5.0A, Administration Manual

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VoIP Configuration
AltiContact Manager Administration Manual 9-9
9.
VoIP
Co
nfigur
at
ion
Network Configuration Guidelines for VoIP
Real-time applications such as voice communications require a networking
environment that meets certain requirements to deliver and maintain good
voice quality. The following network configuration guidelines are highly
recommended when using AltiWare’s VoIP features. ISP/Intranet Quality
of Service (QoS)
• If you subscribe to the public IP network or use your own Intranet,
make sure the maximum network delay is less than 150 milliseconds.
• Also, the typical packet loss rate should be less than 5 percent.
WAN Bandwidth
• G.711/G.723/G.729 compression and bandwidth requirements:
(for example, a Multilink Point-to-Point Protocol (MLPPP) or Frame
Relay Forum (FRF), with no Voice Activity Detection (VAD)
running)
— G711 10ms packet frame = 100.8 kbps
— G711 20ms packet frame = 82.4 kbps
— G711 30ms packet frame = 76.3 kbps
— G723 30ms packet frame 6.4k rate = 18.7 kbps
— G729 20ms packet frame = 26.4 kbps
— G729 30ms packet frame = 20.3 kbps
• When a small data application (e.g. one FTP transfer session) is
running across the same WAN as AltiWare IP, make sure bandwidth
is reserved for data traffic. An example would be, if you have 64 kbps
WAN link, you can run one G.723.1 session concurrently with one
FTP file transfer session, provided that the router fragments each TCP
packet to 500 bytes.
• The Jitter Buffer should be adjusted according to the bandwidth
allocated to data traffic. For example, a long Ethernet packet
(approximately 1500 bytes) traversing through a WAN which is
allocated with 256 kbps of data traffic bandwidth will take about 50
milliseconds. The Jitter Buffer value should be set to this WAN link
transmission delay plus the typical network jitter delay. Refer to
“Triton VoIP Trunk Configuration” on page 7-20 for more information
on how to configure the Jitter Buffer.