Quality of Service Blog

Asterisk provides tool for reporting QoS.

It can be actived by adding fallowing rule to given context:

exten => h,1,Set(CDR(userfield)=${RTPAUDIOQOS})

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In that case all metrics would be added at the end of CDR file. Default it is Master.csv located at /var/log/asterisk/cdr-csv/

Added fields look like this:
ssrc=408070608;
themssrc=12192;
lp=0;
rxjitter=0.000581;
rxcount=376;
txjitter=0.000031;
txcount=399;
rlp=0;
rtt=0.000000

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Explanation of fields could be found at http://wiki.kolmisoft.com :

• Our Receiver
  • ssrc – our synchronization source
  • rxcount – no. received packets/Received packets
  • lp – lost packets/Lost packets
  • rxjitter – our calculated jitter(rx)/Jitter

• Our Sender
  • themssrc – their synchronization source
  • txcount – transmitted packets/Sent packet
  • rlp – remote lost packets/Lost packets
  • txjitter – reported jitter of the other end/Jitter
  • rtt – round trip time/RTT