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What the difference between packet delay variation and jitter ?



I used a voip sensor for 3 days to evaluate the performance of a wireless link. The following data obtained:

  • Packets Lost 0%
  • Out of Order Packets 0%
  • Duplicated Packets 0%
  • Jitter Min: 0 ms
  • Average 4 ms jitter
  • Max 5 ms jitter
  • Packet Delay Variation Min -30 ms
  • Packet Delay Variation Average 0 ms
  • Packet Delay Variation Max 41 ms

What is the difference between the jitter and packet delay variation? How to interpret this values ?

Thank you


jitter packet-sniffing voip-sensor

Created on Apr 20, 2011 12:30:22 PM

Last change on Apr 20, 2011 1:43:34 PM by  Daniel Zobel [Product Manager]

1 Reply



Dear Dominic,

the OoS Sensor measures Jitter and Packet Delay Variation according to RFC 3550 and RFC 3393. Please see the IETF Website for exhaustive information.

In RFC 3393, please also see the section regarding terminology:

1.1. Terminology

   The variation in packet delay is sometimes called "jitter".  This
   term, however, causes confusion because it is used in different ways
   by different groups of people.

   "Jitter" commonly has two meanings: The first meaning is the
   variation of a signal with respect to some clock signal, where the
   arrival time of the signal is expected to coincide with the arrival
   of the clock signal.  This meaning is used with reference to
   synchronous signals and might be used to measure the quality of
   circuit emulation, for example.  There is also a metric called
   "wander" used in this context.

   The second meaning has to do with the variation of a metric (e.g.,
   delay) with respect to some reference metric (e.g., average delay or
   minimum delay).  This meaning is frequently used by computer
   scientists and frequently (but not always) refers to variation in

   In this document we will avoid the term "jitter" whenever possible
   and stick to delay variation which is more precise.

Created on Apr 20, 2011 1:51:35 PM by  Daniel Zobel [Product Manager]

Last change on Apr 20, 2011 1:52:10 PM by  Daniel Zobel [Product Manager]

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