How much bandwidth do I need for SIP trunks?

How much bandwidth do I need for SIP trunks?
This depends on the type of codec (the mechanism used to compress the voice traffic over IP) and the number of simultaneous calls. Broadvox uses G.711 and G.729. G.711 is considered “higher quality” and usually consumes about 88 Kbps (with overhead). G.729 consumes about 38 Kbps. Most of our customers choose the G.729 codec because they get more use out of their bandwidth. We personally cannot hear the quality difference between the two codecs.