[Asterisk-Users] Actual audio bitrates

[Olle E. Johansson]

Eric Wieling wrote:
 >>I was just measuring the bitrates of a couple of codecs via iax. I'm getting
 >>much higher numbers than expected, so maybe I'm doing something wrong?
 >>
 >>Measured with iptraf, values displayed are:
 >>codec: measured bitrate (bitrate according codec definition)
 >>
 >>gsm: 52 kbps (13 kpbs)
 >>alaw: 154 kbps (?)
 >>speex: 57 kpbs (24 kpbs)

> Check the mailing list.  There are several messages addressing the
> issue.  The main cause of the extra bandwidth usage is IP and UDP
> headers.  VoIP sends small packets and so, many times, the headers are
> actually much larger than the data part of the packet.  IAX2 trunking
> helps with the IP overhead, but only when you are sending more than 2 or
> so calls between the same Asterisk servers.
Good explanation. Stolen... :-)

http://www.voip-info.org/tiki-index.php?page=Bandwidth+consumption
Updated.

/O