How to Generate QoS Events from RTP Flow

This page describes how to generate Qos from the RTP flow recorded over an Ethernet interface. This is acheived by using the "Analog" properties in the Clarinet filter used on-line (filter name defined in the profile) or off-line (Filter-Run Protocol).

Setting the test conditions

The Clarinet-Book USB unit connections and the test condition settings for basic VOIP communication are detailed in the following pages:

Setting the test conditions for VOIP / Analog filter

The protocol filter file Lan_auto_rtp_analog_ref.acf (created with the Wizard from the Template list) specifies the protocol stack and includes a reference file for Qos Measurement.

As the IP protocols are automatically detected by the protocol value, the stack defined in the "Protocol specification" has layers D3 to D7 set to "Automatic". The RTP protocol is decoded at level 5, the "analog" protocol is added to level 6.

The"Analog Measurement" tab of the filter includes specifications for both functions: wav file generation and QoS measurement. The filter file Lan_auto_rtp_analog_ref.acf  is configured  to generate wav files and QoS events with a reference file (default is or137.wav). The default reference file should be copied manually from C:\Clarinet\Clatools\Template\L A N (Ethernet - IEEE 802.3) to the current directory.

  • Modifications of the filter to apply in "Received Voice" part:
    • The codec specifications must correspond to the value set in the PT of the RTP messages.
      For information:
      • PT=000 è G711 mLaw
      • PT=008 è G711 ALaw
      • PT=018 è G729
    • If disabled (no output file), only Qos measurement will be processed:
      • The file name (default= Rtp_analog.wav)
      • The encoding specifications of the file.wav
    • If enabled the output file should specify:
      • The file name (default= Rtp_analog.wav)
      • The encoding specifications of the file.wav
  • Modifications of the filter to apply in "Quality measurement" part:
    • The quality measurement should be set to "Continuous", "One Time"  or "Auto" 
    • The reference file name is optional 
    • The "Delay between measurement" defines the period of generation of  "Average" events.

Setting the test conditions for processing basic QoS events

The generation of basic QoS events provides:

  • The value of the Jitter
  • Periodically, Average events for jitter and packet loss.

The generation of basic QoS events depends on the mode and reference file specifications :

Mode  Reference file Results in event file
Continuous No Jitter for RTP packet (2->N)
Continuous Yes Jitter for RTP packet : begin (ref file) ->N
One time No Jitter for RTP packet (2->N)
One Time Yes
  • Beginning + End of meas (1st ref file)
  • Jitter for RTP packet : begin-end (1st ref file)
  • Average (1st ref file)

Setting the test conditions for processing PESQ QoS events

The generation of PESQ QoS events provides the PESQ value in Average events:

  • The value of the Jitter
  • Periodically, Average events for jitter, packet loss and PESQ value.

When the PESQ resource is selected in Generator/Responder of IP profile, the generation of PESQ QoS events requires the following specifications:

Mode  Reference file Synchro PESQ Results in event file
Auto Yes Yes Yes
  • Beginning +End of  meas (each ref file)
  • Jitter for RTP packet : begin-end (each ref file)
  • Average (each ref file)

Applying the filter conditions

The processing of the events can be done:

  • Off-line by using Filter èRun Protocol:
    • Source file including the RTP flow (Lan_mon.ace as an example).
    • Filter name (Lan_auto_rtp_analog_ref.acf  as an example)
    • Result file.generated (Lan_mon_rlt.ace as an example).
  • On-line, at the end of the profile execution, with the following settings:
    • Configuration file set as WI_ANALOG by Clarinet-Init
    • Filter name defined in the profile to be execute
 
Related topics:
Generation of Analog events
Analog filter specifications
 

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