Leaning Guide: What causes VoIP QoS problems?

We have come to measure quality of packetized voice service by the equivalent service offered by the switched digital network, sometimes called G.711 (Ref. 1) service. The user expects a quality of service (QoS) as good as he/she would get on a PSTN dial-up connection.

To achieve this goal, VoIP designers were faced with the following degradations:

  • Mouth-to-ear delay;
  • Impact of erred frames (packets);
  • Lost frames (packets);
  • Variation of packet arrival time, jitter buffering;
  • Prioritizing VoIP traffic over regular Internet and data services;
  • Talker echo;
  • Distortion;
  • Sufficient bit rate capacity on interconnecting transmission media;
  • Voice coding algorithm standardization;
  • Optimized standard packet payload size;
  • Packet overhead; and
  • Silence suppression.

Return to the How does VoIP work? main page.
Go to Section 3: How does VoIP work?

This was first published in June 2006

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