Solved

how to calculate delay jitter given delay.

Posted on 2007-04-10
1
3,925 Views
Last Modified: 2008-01-09
Hi experts,

I understand that delay jitter is the variation of delay in network packet measurement.
So given delay, how do I calculate delay jitter?
If delay jitter is the variance, can I use the usual statistic variance formula var(X)=E(X^2)-E(x)^2?
If my delay is given in millisecond, what is the unit of delay jitter?
0
Comment
Question by:help-me
1 Comment
 
LVL 3

Accepted Solution

by:
jimmyd072298 earned 50 total points
ID: 18994624
Not really the actual function is a simple example of a class of estimators called "recursive prediction error" or "stochastic gradient algorithms".  .Think about as a recursive running average.  To calculate you have to remember that nothing is known about absolute transit times, the differences in packet transit times are independent of absolute clock values. If packets i and j are time stamped with timestamps Si and Sj when they are sent and are received at times Ri and Rj, respectively, then Dij = (Rj-Sj) - (Ri-Si) = (Rj-Ri)-(Sj-Si) is the difference in transit times in time stamp units. Knowing that then jitter is a smoothed function of |Di-1,i|:Ji = Ji-1 + ( |Di-1,i| - Ji-1 )/16 = 15/16 * Ji-1 + 1/16 * |Di-1,i|
Thus, jitter is a sort of running average of all |Di-1,i| from the beginning of the measurement up to the current packet. Recent packets have a larger weight than older packets. The jitter curve needs about 100 packets to stabilize.
0

Featured Post

Courses: Start Training Online With Pros, Today

Brush up on the basics or master the advanced techniques required to earn essential industry certifications, with Courses. Enroll in a course and start learning today. Training topics range from Android App Dev to the Xen Virtualization Platform.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Join Greg Farro and Ethan Banks from Packet Pushers (http://packetpushers.net/podcast/podcasts/pq-show-93-smart-network-monitoring-paessler-sponsored/) and Greg Ross from Paessler (https://www.paessler.com/prtg) for a discussion about smart network …
When you try to share a printer , you may receive one of the following error messages. Error message when you use the Add Printer Wizard to share a printer: Windows could not share your printer. Operation could not be completed (Error 0x000006…
Get a first impression of how PRTG looks and learn how it works.   This video is a short introduction to PRTG, as an initial overview or as a quick start for new PRTG users.
Here's a very brief overview of the methods PRTG Network Monitor (https://www.paessler.com/prtg) offers for monitoring bandwidth, to help you decide which methods you´d like to investigate in more detail.  The methods are covered in more detail in o…

776 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question