Voice Over Internet Protocol (VOIP)

Bandwidth Requirements

One common misconception about VOIP is that it is a bandwidth hog, when, in fact, voice is a very efficient type of traffic. Voice compression standards like G.729 (8:1) and G.723 (10:1) are used to minimize the bandwidth required for voice. G.723, for instance, is the maximum compression rate and requires only 5.3K bps (plus an added 7-8K bps for IP overhead). Even at maximum compression, your VOIP solution will still provide near toll-quality voice. As a rule of thumb, 14K bps of bandwidth per call is ideal. This includes the compressed voice packet and the IP overhead.

To determine total VOIP bandwidth needed per location, take the number of VOIP channels being used and multiply by 14K bps. Then double this number to accommodate for both voice and data traffic. It should also be noted that bandwidth is used only when someone is speaking. A silence suppression/Voice Activation Detection (VAD) feature is an option that frees unused call bandwidth for data traffic. This is significant, since callers are usually silent for 60 percent of the call.