7signal and Avans University of Applied Sciences conducted a trial of 7signal Sapphire WIFI/WLAN Performance Optimization and Assurance solution. This example report shows baseline results from Learning Center. See how WLAN behaves under heavy load from end user point of view. Avans network had been carefully planned, implemented and maintained using industry best practices, supplier provided WLAN management tools and laptop based special purpose WiFI analyzer tools. Follow later phases and results of optimization work from 7signal.com/blog

1. WLAN performance baseline report
Avans University of Applied
Sciences, Netherlands
7signal Sapphire Trial
Baseline Report
March 21st, 2013

2. WLAN performance baseline report
Background
• Avans University of Applied Sciences is looking for an efficient solution to optimize
and maintain Campus WLAN network performance
• A three week onsite Trial of 7signal Sapphire was agreed
• 7signal Sapphire with one 802.11 b/g/a/n Sapphire Eye device was deployed to
Learning Center 1 during week 8. Eye was installed to in Learning center, floor 1
ceiling. 7signal software runs in Avans Linux server.
• Target of the Trial was to find out how WLAN service performs in Learning Center.
• Sonar server (test end point in LAN) is in the same subnet as Carat server
• Automated measurement profile has been running since February 21th
– Profile covers ”Eduroam” BSSID at 2.4 GHz and at 5 GHz
– 4 AP’s with total of 8 BSSIDs were assigned to one Eye unit
• The purpose of this Trial is to provide Avans University of Applied Sciences an
opportunity to get familiar with the product.
• This Trial does not include optimization of the network performance. No actions
were yet taken to improve network performance.
2

3. WLAN performance baseline report
Eye Location: Floor 1 –Learning Center
3
3
2
1
4
5
6
7signal Eye
First Floor:

4. WLAN performance baseline report
4
• The following daily average metric’s do not meet
target: Client attach success rate, Latency, FTP
Throughputs DL/UL, VoIP MOS DL/UL scores
2.4 GHz Eduroam SLA Table
Off-peak Hours / On-peak Hours Comparison
Weekend
Weekend
Busy-Hours (9:00–15:00)
SLA Target limits
Network performance is insufficient
during weeks and especially during
the daytime

5. WLAN performance baseline report
2.4 GHZ BAND
END-TO-END PERFORMANCE
5

6. WLAN performance baseline report
2.4 GHz Attach Success Rate (Daily Average)
6
• At times, attach success rate seems to to drop to zero with for example
AP001080, even though the radio is active and sending beacons. (This needs
to be studied in more detail)
Target level 90%
AP 1080 not
accessible

7. WLAN performance baseline report
2.4 GHz Attach Success Rate (One Week, hourly)
7
Busy Hour effects on
attach success rates
Weekend
Target level 90%
• Attach success rate degrades significantly during high load
• AP 1082 does allow Eye connections. (This needs to be studied in more detail)

8. WLAN performance baseline report
2.4 GHz Downlink Throughputs, daily
8
• Daily average values are on acceptable level
Weekend

9. WLAN performance baseline report
2.4 GHz Downlink Throughputs, hourly
9
The DL throughput declines on
average level to 1-7 Mbps on
Busy Hours. Peak Hours are
usually 11:00-12:00
• During the day time, hourly average thoughputs collapse remarkably, some
of them to sub 1 Mbit/s level. This is likely insufficient level for end users.
At 13.00
0.52Mbit/s At 11.00
0.17Mbit/s

10. WLAN performance baseline report
10
2.4 GHz Downlink Throughput (2 Days), hourly
Throughput declines at 8:00
on weekdays and return
after 16:00
At 11.00
0.17Mbit/s
• Strong daily pattern and very low throughput values in some APs during
the daytime

11. WLAN performance baseline report
2.4 GHz Uplink Throughputs, daily
11
• Daily average values mostly on acceptable level
Weekend

12. WLAN performance baseline report
2.4 GHz Uplink Throughputs, hourly
12
The UL throughput declines
on average level to 1-10
Mbps on Busy Hours. Peak
Hours are 11:00-12:00
• During the day time, uplink hourly average thoughputs collapse remarkably,
some of them to sub 1 Mbit/s level. This is likely insufficient level for end users.
At 12.00
1.1Mbit/s
At 10.00
0.6Mbit/s
Very good performance
when network is empty

13. WLAN performance baseline report
2.4 GHz Uplink Throughput (2 Days), hourly
13
Throughput declines at 8:00
on weekdays and return
after 16:00
At 11.00
0.74Mbit/s
• Like doewlink, also uplink day time, hourly average thoughputs collapse
remarkably, some of them to sub 1 Mbit/s level

14. WLAN performance baseline report
2.4 GHz VoIP MOS Downlink Quality
14
Target level for
MOS 3.6
Downlink MOS declines on
busy-hours but there are also
some drops at times when
there are no traffic on WLAN
• During the day time, hourly average thoughputs
degrade significantly

15. WLAN performance baseline report
2.4 GHz VoIP MOS Uplink Quality
15
Target level for
MOS 3.6
Uplink MOS declines
clearly declines on busy
hours
• During the day time, hourly average thoughputs
degrade significantly

16. WLAN performance baseline report
2.4 GHz Downlink Jitter
16
• Jitter increases significantly with the load

17. WLAN performance baseline report
2.4 GHz Uplink Jitter
17
• Jitter increases significantly with the load
• Uplink increases more than downlink

18. WLAN performance baseline report
2.4 GHz Downlink Packet Loss
18
Target level 0.5%
• Packet loss increases significantly with the load

19. WLAN performance baseline report
2.4 GHz Uplink Packet Loss
19
Target level 0.5%
• Packet loss increases significantly with the load
• Uplink packet loss higher than downlink

20. WLAN performance baseline report
2.4 GHz Latency
20
• Latency increases significantly with the load
Target level 50ms

21. WLAN performance baseline report
2.4 GHZ
DATA RATES AND RETRIES
21

22. WLAN performance baseline report
2.4 GHz – Downlink Data Rates in Synthetic Eye tests
22
• High data rates used when there is no other traffic in WLAN.
• During busy hours the data rates vary a lot and low values also used

23. WLAN performance baseline report
23
2.4 GHz –Uplink Data Rates in Synthetic Eye Tests
• There is no big difference in UL direction with data rates when comparing
off-peak hours and on-peak hours. Mainly good data rates in use.

24. WLAN performance baseline report
AP 1076 2.4 GHz data rate usage
Downlink (AP to client)
24
• Low datarate usage from AP to clients
Undesirable
low codecs

25. WLAN performance baseline report
AP 1076 2.4 GHz data rate usage
Uplink (Client to AP)
25
• Low datarate usage from clients to AP
Undesirable
low codecs

26. WLAN performance baseline report
2.4 GHz AP Retransmissions towards clients
26
Undesired
behavior
• High amount of retries reduce network capacity and daytime throughput
10% limit for
data traffic

27. WLAN performance baseline report
2.4 GHz Client Retransmissions towards AP
27
Undesired
behavior
10% limit for
data traffic
• High amount of retries reduce network capacity and daytime throughput

28. WLAN performance baseline report
2.4 GHz Eye Retransmissions in Synthetic Tests, hourly
28
• High amount of retries in active tests

29. WLAN performance baseline report
SPECTRUM AND
INTERFERENCE
29

30. WLAN performance baseline report
2.4 GHz Spectrum Graph
30
Bluetooth interference presence on
busy hours
On off-peak hours the specturm
graph shows an clean 1-6-11 WLAN
utilization
• Bluetooth interference has negative impact on WLAN receiver performance
at AP and client

31. WLAN performance baseline report
31
2.4 GHz Average Spectrum (Busy Hours)
WLAN
Spectrum,
Ch 1
WLAN
Spectrum,
Ch 6
WLAN
Spectrum,
Ch 11
• Clear 1-6-11 WLAN channel deployment.
During Busy Hours the energy level on
adjacent channels is around -82 dBm
• Average interference level is 20 dB lower on
the interim channels during off-peak hours
WLAN Average Spectrum on off-
peak hours (On weekend)

32. WLAN performance baseline report
32
2.4 GHz Max Spectrum (Busy Hours)
WLAN
Spectrum,
Ch 1
WLAN
Spectrum,
Ch 6
WLAN
Spectrum,
Ch 11
Bluetooth creates 1 MHz seperated
spikes to spectrum
• At times, Bluetooth interference is on same level than the received signal
strength from WLAN Access Points

33. WLAN performance baseline report
RADIO ENVIROMENT,
CONFIGURATION AND
UTILIZATION
33

34. WLAN performance baseline report
Radio channels at 2.4 Band
34
Well organized 1-6-11 channel
plan. No adjancent channel
interference from other APs

35. WLAN performance baseline report
Channel allocation and changes
35
• No channel changes over the measurement period

36. WLAN performance baseline report
2.4 GHz Number of SSID/MAC–pairs per channel
36
• Rather well balanced 3 channel plan

37. WLAN performance baseline report
Number of Clients in ”Eduroam” 2.4 GHz APs
37
On Busy Hour the usage is
really high. AP001080 shows
over 50 clients at times
• Number of concurrent active clients per Access point Radio should be max 20
clients to keep up a sufficiently good performance

38. WLAN performance baseline report
2.4 GHz WLAN Traffic Utilization
38
Frame GI Frame GI Frame
= 100% WLAN traffic utilization
Beacon
GIGIGI
The 7signal WLAN air
time utilization can
show over 100% results
if there are more
packets in the air than
properly GI separated
(no –overlapping)
packets allow
Busy Hour WLAN utlization
is on high level. This AP
serves over 50 clients at
times
• Air time is severly congested during
busines hours
• This limits available thoughputs
significantly

39. WLAN performance baseline report
SUMMARY AND
CONCLUSIONS
39

40. WLAN performance baseline report
Observations/opportunities for improvements,
2.4 GHz band
• 3 channel plan with 802.11n HT20. Channels are rather evenly allocated. No
channel changes, automated channel allocations disabled (good)
• Many AP’s have 802.11b rates enabled
• Network is severely congested during daytime, throughputs drop regularly
below 1 Mbit/s
• Load is unevenly distributed. AP 1078 has at times over 65 clients.
• Bluetooth like interference detected during daytime. It impacts negatively to
WLAN performance
• Retry rates are high and datarates unnecessarily low
• WLAN air time utilization is very high during daytime
• Performance less than optimal
– High interference from Bluetooth and own WLAN traffic -> high retries ->
low data rates -> air time congestion -> capacity runs out during daytime
40

41. WLAN performance baseline report
Suggestions
• Network performance can be significantly enhanced by optimizing it and maintaining
the performance with End-to-End Key Performance Indicators (KPI’s)
• Deploy Sapphire Eyes to other areas that require optimization and better WLAN
performance. Take baseline there also.
• Perform Optimization, key areas for improvement in Learning Center include
– Reduce WLAN airtime utilization levels through WLAN parameter optimization
• Utilization can likely be reduced by 50-70% through this process
• This increases capacity and is expected to improve daytime minimum
throughputs up to several 100%’s
– Make radio more robust against Bluetooth interference
• This lowers retries and reduces also further utilization
– Balance load through power settings and AP positioning
• This will allow more capacity and better user experience during peak load
– Investigate AP 1082
• Reboot as the first action. Observe then impact. T-shoot further if needed
– Other items to be defined after initial steps
• Maintain Achieved Performance through proactive KPI driven actions
41

42. WLAN performance baseline report
HOW DOES YOUR NETWORK PERFORM?
- Connectivity, throughput, latency, packet loss, jitter, MOS…
Contact 7signal to learn more about 7signal Sapphire Performance Assurance and
Optimization products and services
www.7signal.com
info@7signal.com
7signal presents at Wireless Field Day #5 in August, 2013. Be sure to join us then
virtually and learn more about this 7signal products and later phases of Avans
University of Applied Sciences network optimization. More information on Avans
results will be also posted to 7signal blog.
42