Bandwidth used by the different codecs
When you are using Voice over IP, the used VoIPVoice over Internet protocol - A digital telephone system that uses the internet as the transmission medium, rather than the PSTN. phones and PBXPrivate Branch Exchange - System that connects telephone extensions and switches calls. can use different so called codecs. The consumption of bandwidth depends on which codec you use.
The following table gives you a short overview of the bandwidth consumption of the different codecs. On the page from asteriskguru.com, you can also find a bandwidth calculator tool.
| codec | name | bandwidth (incl. overhead) | bandwidth for 5 concurrent calls | quality |
|---|---|---|---|---|
| G.711 a/u-law | PCM | 80 kbit/s | 512 kbit/s | ISDNIntegrated services digital network - A technology enabling digital transmission of data and voice signals over a telephone network. |
| G.729 | CS-CELP | 32 kbit/s | 200 kbit/s | good |
| iLBC | iLBC | 32 kbit/s | 200 kbit/s | good |
| G.723.1 | MP-MLQ | 21 kbit/s | 110 kbit/s | average |
| G.723 | A-CELP | 15 kbit/s | 80 kbit/s | average |
| GSM fullrate | GSM | 13 kbit/s | 80 kbit/s | average |
| G.726 | AD-PCM | 55 kbit/s | 386 kbit/s | GSM |
| SpeeX | SpeeX | 4 - 15 kbit/s | 25 - 80 kbit/s | variable |