Frequently Asked Questions

Bandwidth for calncall / callacould / cloudtokyo

Understanding Bandwidth for calncall / callacould / cloudtokyo
overhead Bandwidth for each calls
  • RTP – 4.8 kbps
  • UDP – 3.2 kbps
  • IP – 8 kbps
  • Ethernet (not using QOS) – 15.2 kbps
The total overhead is 31.2 kbps.

Codec Audio Quality CPU Resources Base Size(KBps) Overheads Total Size (Base + Overhead)
G711 A/U Good Very Low 64 31.2 95.2 kbps
G722
Very Good Low 64 31.2 95.2 kbps
GSM Acceptable Average 13 31.2 44.2 kbps
G729 Average High 8 31.2 39.2 kbps

The above are stats for one audio stream. A VoIP call will use one audio stream for each leg (or endpoint). Thus a call between two parties will use double the bandwidth shown above.

All our service primary codec would be 711A and secondary are 729 .

Note that the above bandwidth consumption is in kilobits per second. You will need to divide by 8 in order to get the equivalent in kilobytes per second. Using the above data, we can come up with the following stats:

Codec Audio Quality CPU Resources Base Size Total Size
(Base + Overhead) Kilobits per second
Kilobytes per second Kilobytes per minute Megabytes per minute Megabytes per minute
(For duplex audio stream)
Megabytes per minute
(For a simple 5 min call)
G711 Good Very Low 64 kbps 95.2 kbps 11.9 714 0.714 1.428 7.14
G722 Very Good Low 64 kbps 95.2 kbps 11.9 714 0.714 1.428 7.14
GSM Acceptable Average 13 kbps 44.2 kbps 5.525 331.5 0.3315 0.663 3.315
G729 Average High 8 kbps 39.2 kbps 4.9 294 0.294 0.588 2.94

Here are some notes and suggestions for the application of specific codecs:

  • G729 is the codec which consumes the least bandwidth and has a relatively good audio quality. However that comes with two drawbacks:
  • Its efficiency comes at a cost, CPU usage. It is more CPU intensive to encode audio in such a low size while maintaining the quality.
  • Although G711 and G722 consume over twice as much bandwidth as the other codecs, most Local Area Networks are able to handle this bandwidth. Using the above table, a 1 hour call using G711 is equivalent to transferring a 41.8 MB file. If that causes an issue, you should consider upgrading your network.

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Last Updated 3 years ago