?
Solved

how to calculate delay jitter given delay.

Posted on 2007-04-10
1
Medium Priority
?
3,930 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 150 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

Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

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

Tech spooks aren't just for those who are tech savvy, it also happens to those of us running a business. Check out the top tech spooks for business owners.
In this article, the configuration steps in Zabbix to monitor devices via SNMP will be discussed with some real examples on Cisco Router/Switch, Catalyst Switch, NAS Synology device.
This video gives you a great overview about bandwidth monitoring with SNMP and WMI with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're looking for how to monitor bandwidth using netflow or packet s…
Monitoring a network: why having a policy is the best policy? Michael Kulchisky, MCSE, MCSA, MCP, VTSP, VSP, CCSP outlines the enormous benefits of having a policy-based approach when monitoring medium and large networks. Software utilized in this v…

807 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