What is the minimum KB of bandwidth required for an IP telephony network built with a VOIP gateway?

Voice over IP bandwidth usually depends on the encoding format used, with G.711 voice encoding a session will create two 64kbps RTP streams, on UDP/IP/Ethernet not all bandwidth is used at all times. An encoding method that sends a 64kbps stream results in a much larger stream for the IP network. the main reason for the extra bandwidth is the IP and UDP headers. When Voice over IP sends small packets, most of the time the header is actually much larger than the data in the packet. The following table lists the various encoding methods, and the bandwidth required:

Encoding Method Encoding Required Bandwidth Actual Network Bandwidth Required

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

When the internal extensions are interconnected, there is no need to worry about insufficient bandwidth as the LAN will have 10M or 100M bandwidth.

When communicating between headquarters and branch offices, assuming that there are 50 people in the headquarters, and settling with a larger convergence ratio, for example, 5:1, i.e., there are 10 concurrent routes at the same time, it takes about 0.1M bandwidth for G.711 encoding, 0.03M for G.729 encoding, 0.02M for G.723 encoding

This is a good example of how to use G.711 encoding.