A1 VoIP Requirements
52 Getting Started
A1 VoIP Requirements
A1.1 Bandwidth Assessment
To establish a VoIP network, you must ensure that the network has enough bandwidth to
support VoIP communications. Inform your network administrator of the required bandwidth,
and make sure that the network can support VoIP communications even under conditions of
maximum network traffic.
Bandwidth Calculation
Provided below is the formula to find out the amount of bandwidth required for VoIP
communications:
Required bandwidth for fax and voice communications for one VoIP channel is shown in the
tables below (for more details, refer to "2.2.3 Voice Communication Parameters" in the VoIP
Gateway Card Programming Guide).
Required Bandwidth for Voice Communication
Via LAN
Via WAN (PPP: Point-to-Point Protocol)
Required Bandwidth
= (No. of Fax Machines × Required Bandwidth for Fax Communication) +
[(4 - No. of Fax Machines) × Required Bandwidth for Voice Communication]
CODEC
Packet Sending Interval
20 ms 30 ms 40 ms 60 ms 90 ms
G.711 87.2 kbps 79.5 kbps 75.6 kbps ——
G.729A 31.2 kbps 23.5 kbps 19.6 kbps ——
G.723.1 5.3 kbps — 20.8 kbps — 13.1 kbps 10.5 kbps
G.723.1 6.3 kbps — 21.9 kbps — 14.1 kbps 11.6 kbps
CODEC
Packet Sending Interval
20 ms 30 ms 40 ms 60 ms 90 ms
G.711 84 kbps 77.3 kbps 74 kbps ——
G.729A 28 kbps 21 kbps 18 kbps ——
G.723.1 5.3 kbps — 18.7 kbps — 12 kbps 9.8 kbps
G.723.1 6.3 kbps — 19.7 kbps — 13.1 kbps 10.8 kbps
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