wifimon nordunet tech workshop 2015
Post on 15-Feb-2017
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WIFIMon
“How to fix WIFI take 2”Dave Wilson, James Healy, Kostas Stamos, Vasileios Kokkinos, Arne
Øslebo, Kurt Baumann, Jan Hertzberg, Brian Bach Mortensen (presenter)
Géant4 - Service Activity 3 Task 3
Problem statement
• Users complain about WIFI performance to local network admin
• Typical solutions:• Network admin checks AP logs or hardware probes (if any)• Send someone to check the installation
• Problem might be solved due to students leaving the room
• If “hard” fault –>• No Problem case solved done
• If “soft” problem à• more data is needed to determine the cause and the fix
• Furthermore, a proactive solutions was sought
Road to a fix
• Problem was raised at the Dublin City University (James Healy)
• They contacted HEAnet (Dave Wilson) thinking that they would have a good-cheap-fast fix to the problem
• Getting all 3 at the same time turned out to be problematic
• HEAnet went to Géant with the idea:• Lets crowd source the performance of the WIFI
installations
Measuring WIFI 1.
• Hardware probes are great for WIFI monitoring
• But they are typically fixed a certain locations
• Users are not!
• They measure probe performance• Users don’t care about probe performance
Measuring WIFI 2.
• Software probes can be run by user device
• They are cheap
• They are abundant (think student devices)
• They (may) represent the performance the user gets
What we need then?
• JavaScript that runs in the users browser that measures
• Bandwidth/Latency• IP Address of the user• Timestamp
What we need then (cont.)?
• DHCP/Radius logs• Mac address of user and access point• IP Address of the user• Timestamp
• This will make it possible to correlate JavaScript measurements with Access Points• Pin pointing problems to specific APs
Client Software
• Rather than implementing measurement JavaScript from bottom we took a look at open source implementations:• Nettest
(https://code.google.com/p/nettest/)• Boomerang
(https://github.com/yahoo/boomerang)• Currently using nettest
• Planning to test Boomerang
Correlation
• Currently we are using Nettest• Correlating the data from JavaScript
with Radius/DHCP • Lets see a simple check:
Basic checking
0
500
1000
1500
2000
2500
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Download rate(KB/s)
Upload rate(KB/s)
Measuring at NT2015
• Not optimal conditions :0(• Only hotel Wi-Fi• No log files to correlate measurements
from JavaScript to AP points• Website did not implement JavaScript
on schedule page• No time to fix it before people where here
• But we did get a few measurements tru…
• 48 measurements as of last night
Bandwidth
• Clearly not all measurements are “good”
Ping
Ping
• Correlation between bad ping and bandwidth• User at edge of Wi-Fi reach?
Statistics
• Mean values• Down, Up, Ping:• 1107KB/s, 476KB/s, 47ms
• Standard deviation• 688KB/s, 194KB/s, 30ms
• Pretty big variance from the mean• So maybe not that good to use for
anomaly detection??
Statistics cont.
• So if the above is normal behavior• How do we detect issues with the Wi-Fi network?
• We probably need to get data from healthy and unhealthy scenarios• Then we can compare the stats and see if there
is big changes in mean/variance etc.• E.g. if enough pings go wrong it will eventually shift
the mean value to a higher point• And perhaps the variation will go down?
• This is of course so far PURE guesswork from my side!
Further Data Validation
• Comparing Data with HW probes is a topic that might reveal the usefulness of WIFImon (and probes)
• Will the probes and the clients see the same degradation
• Or will one “party” have an edge?• Whatever the result it might be a good
way to detect problems to correlate the varios measurements
Summary
• We got the basis for doing a more throughout validation
• We do need a lot more data to make any attempt on drawing conclusion
• If you want to participate with data collection• Do not hesitate to contact us
• We have a small agile team• Changes are made on a daily basis
• With your help we will know if worth continuing!
Thanks
• All from the WIFIMon team• Erik Kikkenborg
• Feel free to contact me or any team member with ideas, suggestions, corrections for further work
E-mail: brian@nordu.net
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