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content:activity:linux.conf.au_2013 [04/06/2013 17:41]
Andrew Bettison re-organise sections, add info about VoMP channel driver trial
content:activity:linux.conf.au_2013 [06/06/2013 15:18] (current)
Andrew Bettison [VoMP channel driver for Asterisk] add conclusions
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 A few [[:content:tech:VoMP|VoMP]] calls were successfully made from the dormitory room when the "Brian" Wi-Fi router was set up connected to the Dell PC server, although audio quality was poor, echo was a problem, and delay tended to build up. A few [[:content:tech:VoMP|VoMP]] calls were successfully made from the dormitory room when the "Brian" Wi-Fi router was set up connected to the Dell PC server, although audio quality was poor, echo was a problem, and delay tended to build up.
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 +**Conclusion:**  [[:content:tech:MDP]] clearly did not cope well in a congested environment, since most [[:content:tech:VoMP|VoMP]] messages were lost.  Adding per-hop retransmissions to [[:content:tech:MDP]] would significantly improve this situation.
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 +**Conclusion:**  [[:content:tech:VoMP]] used a very inefficient audio codec ([[http://en.wikipedia.org/wiki/G.711|µ-Law or A-Law]], 8kHz sample rate, 8 bit resolution) which generates 160 bytes per 20 ms packet, or 8kB per second.  Changing to [[:content:tech:CODEC2 support|use CODEC2]] would dramatically reduce the data rate over the air per call.
  
  

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