Comment Re:VoIP and broadband (Score 1) 426
including the overhead of the other layers, VoIP requires only ~120kbps.
Never fear - Pedantic Man is here!
A better estimate would be 167 kbps.
Since anyone listening to Pedantic Man will surely want an explanation, here it is.
Assuming a rather typical VOIP scenario with call signaling via SIP and media traffic chunked into 20 ms pieces and sent via RTP packets transported over UDP:
There will only be a few SIP packets per call, and they are not very large, so even Pedantic Man is willing to ignore their impact on bandwidth.
G.711 itself requires 8000 bytes / second. This comes to 160 bytes per 20 ms packet. After the RTP and UDP overhead is added, each 20 ms packet will be 214 bytes. There will be
214 bytes * 8 bits/byte * 50 packets/sec * 2 directions = 171200 bits / second
(171200 bits / second) / (1024 bits / kb) = 167.1875 kbps