percentil calculator

[rashid2014]

hello
please i don't understand this part on NNa? how can use it? it sait percentile in 95 why?
can you explain me simply? thanks

[jolson]

If my understanding is correct, you can think of the Percentile calculator as an advanced 'average' calculator. The description on Nagios Network Analyzer itself is as follows:

The percentile calculation is done by taking samples of the data over a period of time you specify. Over that time period you get an amount of samples. Say you have 1000 samples. Each sample is of 5 minutes. A fairly common calculation is for the 95th percentile for billing. With 1000 samples, we will order the samples from smallest to largest size. We then take 5% of the samples off the higher side. We then take the leftover highest sample and that is the 95th percentile. We will generate a graph which shows a visual example of how we come to the conclusion on the right-hand side of the calculation area when a calculation is completed.

In basic terms, you select a couple of variables - the time range, and the percentile. For most purposes, you can leave the percentile at 95 - according to the above, that is a common billing percentile.
What happens is that Nagios Network Analyzer will analyze all bandwidth information in the time period specified - and order it from most to least usage in 5-minute increments.

Let's pretend that we selected April 1st - April 3rd with 5 minute sample sizes.
A small snippit of information may show the following:

Code: Select all

192.168.1.1 - 50Mbps/5 min - April 1st
192.168.1.1 - 49.8Mbps/5 min - April 1st
192.168.1.1 - 49Mbps/5 min - April 3rd
192.168.1.1 - 36Mbps/5 min - April 2nd

Of course this example is simplified, but I hope it helps you get an idea of how Network Analyzer would stack the information. It's based on usage per sample size - the sample size is 5 minutes.

After stacking the information, NNA will shave the top 5% off. If you had 100 entries, 5 entries would be cut off of the top, leaving 95 entries (hence 95th percentile). The new top entry would be your 95th percentile. This could be used if you were charging a client based on their bandwidth usage or similar.

Does that help? Let me know if you have questions.