Voice Trunking Calculator
Calculates the number of trunks and estimated VoIP bandwidth required to support the total
erlangs in a site using using Erlang B
The total is comprised of up to 6 calling profiles and the associated codecs.
An erlang is essentually the percentage of an hour a phone is active. A value of .2-.3 are common values.
More active phones would have a higher erlang.
Bandwidth is estimated by averaging the individual profiles erlangs against the total erlangs.
Keep in mind the peak could always be higher.
When calculating the bandwidth the following values are used:
| Bandwidth (kbps) || Codec |
| 26.8 || G.729A (CS-CELP) 8kbps compression |
| 82.8 || G.711 (PCM) 64kbps uncompressed |
| 17.9 || G.723.1 (ACELP) 5.3kbps compression |
| 18.9 || G.723.1 (MP-MLQ) 6.4kbps compression |
| 50.8 || G.726 (ADPCM) 32kbps compression |
| 28.5 || G.728 (LD-CELP) 16kbps compression |
The Blocking ratio is the number of calls that would be blocked. .01 is 1 call in a hundred.