Data Collection for Latency – Demo Pt 5.1

Now its time for me to collect data from the Signpost Diagnostics Application and Iperf to see if there is a statistically significant difference between the Latency and Goodput data from the two applications. [Jitter will soon be added to the application so I will need to go back the test that]

THE PLAN…

Part A – Data from Signpost Application

  1. Connect the android phone (the client) and laptop (the server) to Internet in such a way that they are behind the same NAT box, so the client can initiate a connection with the server from a private IP address
  2. Set up the OCaml Server running on my laptop
  3. Change in client IP address in the client code and load onto android phone
  4. Running client with server, collecting data whilst viewing output from log files

Part B – Latency data from Ping

  1. Workout how to send pings bothways
  2. Workout how to use ping to get RRT bothways
  3. Collect some data on latency

Part C – Compare Data from Signposts Application and Ping

  1. Extract sufficient data from both methods
  2. Get data from both method into a suitable format
  3. If required, convert units for latency so all data in same units
  4. Compare data
  5. Answer the Question: Is there a significant difference between the data collected by Ping (assumed to be accurate) and the Signpost Application

AND THE REALITY…

Part A

I’ve just been send the most recent version of the Signpost Diagnostics Application as a .apk file. I uninstall the old version of the application using the Android GUI and install the new version using:

cd /android-sdk-linux/platform-tools
./adb install ~/Downloads/SigcommDemoAndroid.apk

I quick come to realize that the above is stage is useless. It will correctly install an application from the .apk file but I need to be able to edit the code of the application so that I can set the client IP address at a later stage

I connect both the client and server to the same Wi-FI network so that the client will be able in initiate an connection with the server

As per usual, to start up the OCaml Server, I will do

cd Downloads/sebastian-SignpostDemo-53ebd3e/SignpostServerOCaml/
./server.native

I uninstalled the last Signpost Application, change the IP address in the code and load onto phone, via Eclipse using the run as dialogue.

Pressing start on the Android application triggers a connection to be initiated with the server, this is successful as the sever outputs a link detailing the android phones name, IP address and port number used.

I can view the logs for this application live, using:

cd  Downloads/android-sdk-linux/platform-tools

./adb logcat-s SIGPST

To filter the output of logcat, I use the arguments -s SIGPST, this gives me a log output such as:

I/SIGPST  ( 1520): Received Latency Upstream: 25500
I/SIGPST  ( 1520): Received Goodput Downstream: 4026
I/SIGPST  ( 1520): Received Latency Downstream: 6008
I/SIGPST  ( 1520): Received Goodput Downstream: 1262925
I/SIGPST  ( 1520): Received Latency Upstream: 49000
I/SIGPST  ( 1520): Received Goodput Downstream: 4787
I/SIGPST  ( 1520): Received Latency Downstream: 10376
I/SIGPST  ( 1520): Received Latency Upstream: 50000
I/SIGPST  ( 1520): Received Goodput Downstream: 2735
I/SIGPST  ( 1520): Received Latency Downstream: 17004
I/SIGPST  ( 1520): Received Latency Upstream: 46500
I/SIGPST  ( 1520): Received Goodput Downstream: 4461
I/SIGPST  ( 1520): Received Latency Downstream: 4463
I/SIGPST  ( 1520): Received Goodput Downstream: 799720
I/SIGPST  ( 1520): Received Latency Upstream: 51000
I/SIGPST  ( 1520): Received Goodput Downstream: 3684
I/SIGPST  ( 1520): Received Latency Downstream: 6875
I/SIGPST  ( 1520): Received Latency Upstream: 307000
I/SIGPST  ( 1520): Received Goodput Downstream: 4670
I/SIGPST  ( 1520): Received Latency Downstream: 8749
I/SIGPST  ( 1520): Received Latency Upstream: 16500
I/SIGPST  ( 1520): Received Goodput Downstream: 2652
I/SIGPST  ( 1520): Received Latency Downstream: 6795
I/SIGPST  ( 1520): Received Goodput Downstream: 24060150
I/SIGPST  ( 1520): Received Latency Upstream: 72500
I/SIGPST  ( 1520): Received Goodput Downstream: 4190
I/SIGPST  ( 1520): Received Latency Downstream: 6809

A quick code inspection, highlights that the latency values are divided by 1000 to be converted into secs, which means that the latency values here are in ms
I will look at how to convert this to a more convenient form in part 3

I can append the output to the file Signoutput.txt using “>> Signoutput.txt”

I have added a sample of Signoutput.txt here 

Part B

I open a remote shell on the android phone using ./adb shell, I then use the ping unix commend from the client to the server, and i get an output such as

24 packets transmitted, 24 received, 0% packet loss, time 23070ms
rtt min/avg/max/mdev = 35.614/90.183/297.302/51.944 ms

The latency will be half the RRT so here it is 45.0915 ms

Then repeating the test from the server to the client and i get an output such as

43 packets transmitted, 40 received, 6% packet loss, time 42070ms
rtt min/avg/max/mdev = 33.371/93.812/241.825/45.579 ms

So the latency is similar to before at 46.906 ms

Now I want to collect the data from the ping output, so I wrote the following bash script to do this:

#!/bin/bash

for i in {1..10}
do
ping 192.168.14.47 -c 10 -n -q >> Pingoutput.txt;
done

This sents 100 pings, in 10 sets of 10 and sent the results of the 10 test to a file called Pingoutput.txt
The first line “#!/bin/bash” mean that this is a bash script, the ping argument “-c 10” means said 10 pings and “-q” means quiet output. >> means append to file.

I’ve added a sample of Pingoutput.txt here

Part C

To analysis the output files, I have written the Java code here. Currently this code is untested

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