Bandwidth Usage and QoS

How much Internet bandwidth do I need for my ipbx calls? This will depend on the codec you are using. When calculating the actual amount of bandwidth, you must take into consideration that every RTP packet has an IP header in addition to the actual data (payload); this header must be transferred along with the data, and therefore requires a certain amount of bandwidth. Since RTP (voice stream) makes use of many small packets, the amount of bandwidth used by IP headers becomes unexpectedly significant. See the table below for estimated
bandwidth usage.

{| style="width: 300px;" class="wikitable"
|- style="background:gray; color:white"
! Codec 
! Bit Rate 
! Nominal Bandwidth
|-
| G711 
| align="center" | 64 Kbps 
| align="center" | 87.2 Kbps
|-
| G729 
| align="center" | 8 Kbps 
| align="center" | 31.2 Kbps
|-
| G723.1 
| align="center" | 6.4 Kbps 
| align="center" | 21.9 Kbps
|-
| G723.1 
| align="center" | 5.3 Kbps 
| align="center" | 20.8 Kbps
|}