The files for the Ping Code were obtained after decompressing ping.tar.Z by the following actions:
The files are stored in ~/home/kishanj/pingdir1 subdirectory
It was found that the NIKHEF ping code had some bugs in calculating the RTT (Round Trip Time) and accumulating the statistical data. The code was then sent back to the author and modified. A new executable "ping2" was created for the modified code.
The output of the modified NIKHEF Ping code now gives us the Median & IQR along with Min/Avg/Max for the obtained Round Trip Times.
At the command prompt, a maximum of 2 values of percentiles can be given using the -z and -Z options and the corresponding RTT values will be displayed at the output.
A sample of the output for the modified NIKHEF Ping code is given below
---- EPAPHUS.SLAC.Stanford.EDU (22.214.171.124) PING Statistics ----
8 packets transmitted, 8 packets received, 0% packet loss
round-trip (ms) min/avg/max = 2.40/3.42/4.67 (std = 0.771)
(median = 3.36) (interquartile range = 1.62)
(10 percentile = 2.40) (60 percentile = 3.56)
The original ping code has a timeout [-t] option, wherein the user can specify the time interval between ping packets. This is a constant interval and remains the same between all packets. The modified version has a new feature [-P option] wherein the time intervals between pings are obtained from the series generated using Poisson's distribution.
The formula used is I-1TI = -log(UI) / l
For e.g.: -
More information on Poisson's distribution can be obtained from http://www.slac.stanford.edu/~warrenm/poisson/pois.htmlBack to Top
Revised 5 August 1999
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