Transcript Wi-Fi Case Studies - Deployment, Troubleshooting and

Wi-Fi Case Studies
Nadeem Akhtar
Principal Wireless Architect, Mojo Networks
Overview
• Case Study 1
• WiFi deployed in hostel of an educational institution
• Focus on identifying cause(s) of poor performance
• Case Study 2: Mall
• Large scale Public WiFi deployed
• Focus on identifying KPIs to measure network quality
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Case Study 1: Educational Institution
• 16 Floor Hostel
• Each floor with 26 rooms, 2 students per room
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Issues
Coverage Holes
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Noisy Neighbours
Issues
Legacy Clients
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Misbehaving Users
Survey Data
Interference
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Client Protocol Distribution
Survey Data
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Proposed Solutions
• RF Issues
• Coverage enhancement by adding
more APs per floor
• To improve 5 GHz usage
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Provide dual-band WiFi dongles
for old laptops
New students to procure laptops
with 802.11 a/b/g/n support
• Enable band steering to offload dualband clients to 5 GHz band
• Enable smart steering to reduce the
number of sticky clients
• Discuss with neighboring WiFi
owners to reduce signal leakage
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• Fair and responsible usage
• Per user BW restriction to prevent
BW hogging
• Prevent the creation of personal
hotspots
• Debar clients which are using static
IP addresses
Case Study 2
1500+ sites
• 8k+ Operational Access Points
Mixed set of sites
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Retail
Hotels
Airports
Schools/Colleges/Universities
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Challenge
How to determine the health
of each AP and overall state
of the network
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Opportunity
Availability of 100s of
performance metrics
Methodology
Identify a basic
set of parameters
which affect the
network
performance
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Isolate a small set
of metrics to
capture AP and
Clients Health
Generate a
composite Health
Index to indicate
overall network
state
Key Metrics
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Tx/Rx Data Rate
Tx/Rx Utilization
Client Count
Session Count/Duration
Tx/Rx Bytes
Retry Rate
RSSI
SNR
RF Quality
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Client Health
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Client Health
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SNR (dB)
Ranking on Five Pointer
Conclusion
0 ≤ 𝑥 < 10
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Poor
10 ≤ 𝑥 < 20
2
Fair
20 ≤ 𝑥 < 30
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Good
30 ≤ 𝑥 < 40
4
Very Good
𝑥 > 40
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Excellent
AP Health
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AP Health
Retry Error %
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Conclusion
> 40%
Ranking on Five Pointer
Scale
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30 < 𝑥 ≤ 40
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Fair
20 < 𝑥 ≤ 30
3
Good
10 < 𝑥 ≤ 20
4
Very Good
0 < 𝑥 ≤ 10
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Excellent
Poor
Performance Health Index
• For measuring the overall health of
the system, we propose a
Performance Health Index
Performance Health Index, ɸ = (α1*x1+ α2*x2)
where, x1 = SNR Rank, x2= Retry Rate Rank
α1 and α2 are weights which reflect the relative
importance of each individual parameter on overall
health of the system.
α1 and α2 are positive numbers such that α1 + α2 = 1
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PHI Value
Conclusion
0≤ɸ<1
Poor
1 ≤ ɸ< 2
Fair
2≤
ɸ< 3
3≤ɸ <4
4≤
ɸ <5
Good
Very Good
Excellent
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