Understanding XML CDR's <call-stats>

19 Apr 2017

      I'm having a bit of trouble interpreting the jitter_ related data that I am
getting out of XML CDR's in an attempt to measure how well a system is
performing.

For example, I place a G.711 call over a private LAN between two idle
systems using PCMU, the originator being static in a continuous loop, and
the destination being "echo", with jitterbuffer_ms=60:200:20

At the 'echo' end, I examine the call-stats section of the XML CDR (below),
and I am not sure what to make of the jitter_ values -- for example
max_variance of 7076.55, and a loss_rate of 116.67 -- as I haven't been
able to determine from the source code thus far what they are measuring,
and what units they are working in.

Any pointers would be appreciated.

Cheers,
Simon

----

  <call-stats>
    <audio>
      <inbound>
        <raw_bytes>817744</raw_bytes>
        <media_bytes>817744</media_bytes>
        <packet_count>4772</packet_count>
        <media_packet_count>4772</media_packet_count>
        <skip_packet_count>51</skip_packet_count>
        <jitter_packet_count>4774</jitter_packet_count>
        <dtmf_packet_count>0</dtmf_packet_count>
        <cng_packet_count>0</cng_packet_count>
        <flush_packet_count>0</flush_packet_count>
        <largest_jb_size>0</largest_jb_size>
        <jitter_min_variance>0.10</jitter_min_variance>
        <jitter_max_variance>7076.55</jitter_max_variance>
        <jitter_loss_rate>116.67</jitter_loss_rate>
        <jitter_burst_rate>115.67</jitter_burst_rate>
        <mean_interval>20.06</mean_interval>
        <flaw_total>0</flaw_total>
        <quality_percentage>100.00</quality_percentage>
        <mos>4.50</mos>
      </inbound>
      <outbound>
        <raw_bytes>812700</raw_bytes>
        <media_bytes>812700</media_bytes>
        <packet_count>4725</packet_count>
        <media_packet_count>4725</media_packet_count>
        <skip_packet_count>0</skip_packet_count>
        <dtmf_packet_count>0</dtmf_packet_count>
        <cng_packet_count>0</cng_packet_count>
        <rtcp_packet_count>0</rtcp_packet_count>
        <rtcp_octet_count>0</rtcp_octet_count>
      </outbound>
      <error-log>
        <error-period>
          <start>1492563921959035</start>
          <stop>1492563927519075</stop>
          <flaws>511194</flaws>
          <consecutive-flaws>0</consecutive-flaws>
          <duration-msec>5560</duration-msec>
        </error-period>
      </error-log>
    </audio>
  </call-stats>

Simon Ditner

Brian West

Simon Ditner

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