Cisco Voice Guru

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Jitter and Typical Voice Quality Symptoms

with 2 comments

The last post generating some buzz on Twitter so I’m going to follow it up with one more.

The command “show call active voice brief” is an engineer’s best friend when it comes to confirming jitter and other call quality issues.

Here is a sample output of the command:

GapFillWithSilence=950 ms
GapFillWithPrediction=1980 ms
GapFillWithInterpolation=0 ms
GapFillWithRedundancy=0 ms
HiWaterPlayoutDelay=350 ms
LoWaterPlayoutDelay=25 ms
ReceiveDelay=29 ms

If you see the following values incrementing at a high rate, then you likely have an issue:

  • GapFillWithSilence = Choppy voice issues
  • GapFillWithPrediction = Synthetic voice issues
  • LatePackets = Jitter

Written by Matthew Berry

May 2nd, 2012 at 10:03 am

Posted in Blog

2 Responses to 'Jitter and Typical Voice Quality Symptoms'

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  1. Hi Matthew

    The fields that you explain aren’t displayed in “show call active voice brief” are displayed in “show call active voice”


    4 May 12 at 9:39 am

  2. Awesome. Thank you for the knowledge, Guru!

    Brian Dubya

    4 May 12 at 12:12 pm

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