Bandwidth usage in VoIP
Introduction
Bandwidth, in a computer network, means the amount of data that can be carried from one point to another in a specific period of time (usually in seconds). It is usually expressed in bits per second (bps), or kilobits per second (kbps), or megabits per second (mbps). In electronic communication, bandwidth is a width of the range of frequency, which electronic signal uses on a given transmission medium.
It is measured in Hertz (Hz) or Megahertz (Hz). Bandwidth is not a connection speed, although it is interchangeably used with a connection speed by most of the internet users. Bandwidth for VoIP.
For voice communication, the bandwidth requirements are more important, since the voice data is bulkier than the text data. A large bandwidth range means more data can be transmitted at greater speed i.e. greater the connection speed, better the voice quality you can get. Below is the list of the bandwidth, associated with the popular technologies and devices –
| Devices or Technologies | Speed | Can be used in VoIP or not? |
| Dial-up modem | Up to 56 kbps | Not suitable for VoIP. |
| ISDN(Integrated Services Digital Network) | Up to 128 kbps | It is suitable for dedicated and fixed service. |
| ADSL (Asymmetric Digital Subscriber Line) | Up to several Mbps | It is suitable, but does not provide any mobility. |
| Wireless technologies (like WiFi, CDMA, GPRS, WiMax etc.) | Up to several Mbps | Some technologies are suitable, but some are limited by sound quality and distance. |
| LAN (like Ethernet etc.) | Up to Gbps (Giga bits per second) | It is best, but limited due to length of wires. |
| Cable | 1 to 6 Mbps | It is suitable but limits mobility. |
VoIP Bandwidth Consumption
VoIP bandwidth consumption generally depends on the type of codec used, and also the IP and UDP headers in the packet. Bandwidth used by the codec’s are –
| Codec | Sample Bit Rate | Nominal Bandwidth Usage |
| G.711 | 64 kbps | 87.2 kbps |
| G.729 | 8 kbps | 31.2 kbps |
| G.723.1 | 6.4 kbps | 21.9 kbps |
| G.723.1 | 5.3 kbps | 20.8 kbps |
| G.726 | 32 kbps | 55.2 kbps |
| G.726 | 24 kbps | 47.2 kbps |
| G.728 | 16 kbps | 31.5 kbps |
| G722_64k | 64 kbps | 87.2 kbps |
| Ilbc_mode_20 | 15.2 kbps | 38.4 kbps |
| Ilbc_mode_30 | 13.33 kbps | 28.8 kbps |