wlan performance optimization at avans university of applied sciences

Avans University of Applied Sciences

About this material

• This is an example of 7signal optimization project and associated reporting

• After baseline collection, 7signal provides a detailed optimization plan

• Based on the this plan, the first changes are implemented. Network

configuration is changed one change at the time. Impact of each change is

analyzed. The following change is decided after impact of previous change

is properly understood

• This report is the third report and summarizes impacts of three implemented

changes. Selected results are presented here as an example

• Optimization project continues still after this report

• After the optimization, network performance is proactively maintained and

managed based on the SLAs, performance alarms and QoE trending

• This material is shared with a generous permission from Avans University of

Applied Sciences (Netherland) Network Administrator Kees Pronk.

1


Avans University of

Applied Sciences Optimization, phase 3 report


Background

Optimization phases so far:

• 5/29 4-channel plan on 2.4 GHz (Learning Center floors 0, 1 2), fixed channels

• 6/3 Beacon interval to 300 milliseconds on both bands

• 6/3 Remove 802.11b support completely and disable MCS 0, 8 and 16

• 6/6 Adjust AP radio power levels on both bands, set fixed levels

• This report includes the results from May 27th (start of project) to June 10th (3rd

optimization done)

• Data is mostly shown as a network level averages (one line) and area/band

averages (one line each)

• NOTE: Lectures ended 6/7. Student still continue to use learning center for

studying. Traffic volume is somewhat reduced from 6/10. This impacts to long

term comparisons

3


AP AND EYE LOCATIONS

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Managed Access Points on Learning Center

2.4 GHz Channels

Ground Floor

1st Floor

- AP000621 - AP000627 - AP000631 - AP000633 - AP001076 - AP001077

- AP000632 - AP000636 - AP001078 - AP001080 - AP001094

5

#13

#5 #13

#9

#1

#5 #9

#1

#5

#13

#1


SLA COMPLIANCE PERFORMANCE AGAINST PRE SET TARGETS

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SLA compliance, daily averages VRS band/area

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SLA targets

Improving clearly


SLA compliance, all targets, daily averages VRS AP

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SLA targets


SLA compliance/target, NW level, (all APs/bands)

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Change 1

Change 2

Change 3 Clearly

improved


SLA compliance/target, floor 1, 2.4 GHz

• One AP at 2.4 GHz was not performing. Reboot on 6/10 seemed to help

• 2.4 GHz need some improvements to improve voice quality related characteristics (jitter, packet loss)

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Change 1

Change 2

Change 3 Improved but would not yet

serve voice traffic well


SLA compliance/target, floor 1, 5 GHz

• Looking good against these targets after change 3

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Change 1

Change 2

Change 3 Clearly improved


SLA compliance/target, ground floor, 2.4 GHz

• One AP at 2.4 GHz was not performing. Reboot on 6/10 seemed to help.

• 2.4 GHz need some improvements to improve voice quality related characteristics (jitter, packet loss)

12

Change 1

Change 2

Change 3

Improved but would not yet

serve voice traffic well


SLA compliance/target, ground floor, 5 GHz

• Looking good against these targets

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Change 1

Change 2

Change 3

Improving, but has been

performing pretty well all

the time


QUALITY OF EXPERIENCE SYNTHETIC TRANSACTION MEASUREMENTS

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Beacon availability

• Ground floor beacon availability is degrading modestly (not remarkable)

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NETWORK AVERAGE BAND/AREA AVERAGES


Radio attach success rate (within 30 seconds)

• Attach success rates improve clearly

• Resetting two “failing” 2.4 GHz APs dragging down averages seems to resolve the last dip. Need to follow up.

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Rebooting 6/10 two non-

performing APs helps

Daily averages

follow slower. Follow up!



IP address retrieval success rate

• Looks good

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Radio attach time

• Looks good

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FTP test success rate

• Performance improves

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VOIP test success rate

• Performance improves

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FTP (TCP) downlink throughput

• Significant improvements at 5 GHz, especially 1st floor

• 2.4 GHz seems to improve as well, especially ground floor

• (Note, load varies also)

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160% improvement in floor 1 5GHz Other also improve


FTP (TCP) uplink throughput

• Significant improvements at 5 GHz, especially 1st floor

• 2.4 GHz seems to improve as well, especially ground floor

• (Note, load varies also)

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400% improvement in floor 1 5GHz Other also improve


VOIP (UDP) MOS (PSQA) downlink

• Especially 2.4 GHz seems to improve slightly

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VOIP (UDP) MOS (PSQA) uplink

• The deepest dips improve significantly

• Small improvement on daily averages

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HTTP throughput downlink

• Clear improvement in all bands/areas

• Deep dips disappear

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60% improvement


Jitter (UDP)

• Clear improvement, but 2.4 GHz could improve still more

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>50% improvement


Packet loss (UDP)

• Clear improvement, but 2.4 GHz could improve still more

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>60% improvement


Latency (RTT)

• Significant improvement

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>30% improvement


Ping success rate


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Retries in synthetic tests by Eye unit

• Overall significant improvement

• 5 GHz floor 1 very large improvement

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20-80% improvement


RADIO PERFORMANCE PASSIVE CAPTURE BASED DATA

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Gross beacon density


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Beacon airtime utilization


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AP retry rate

• A small improvement. This could be improved more.

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Client retry rate


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Gross probe density

• Some improvement, but may is directly traffic volume related

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Gross probe response density

• Some improvement, but may is directly traffic volume related

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Probe response airtime utilization

• Some improvement. 2.4 GHz needs to improve further

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WLAN traffic airtime utilization

• 2.4 GHz utilization has improved (become smaller)

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Frame GI Frame GI Frame

= 100% WLAN traffic utilization

Bea

con

GI GI GI

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



Probe response density

• Somewhat less probe responses (positive)

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Management traffic density

• Significant reduction in management traffic

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Aggregate traffic density towards AP

• Varies alot

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Aggregate traffic density from AP

• 2.4 GHz floor 1 seems to get a bit lower (positive)

• 5 GHz seems to increase (desirable trend)

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CLIENT AND AP DATA RATES PASSIVE CAPTURE,

COMBINED 2.4 AND 5 GHZ

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Uplink 5/27 00:00-23:59 VRS 6/10 00:00-23:59

• Combination of 2.4/5 GHz

• Clients use slightly higher

data rates. Variance

remains.

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Less small data rates

Before

After


Downlink 5/27 00:00-23:59 VRS 6/10 00:00-23:59

• > 5 samples

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• Combination of 2.4/5

GHz

• APs data rates are

more centered around

max but variance

remains

Before

After


CHANNELS AND SPECTRUM

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2.4 GHz channel allocation 6/10

• Some APs of old 3 channel plan remain and may interfere slightly

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Remaining from 3

channel plan

Remaining from 3

channel plan

Remaining from 3

channel plan


5 GHz channel allocation 6/10

• Only 4 channels really used at 5 GHz

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Spectrum – Learning Center, Ground Floor

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Channel 1 Channel 5 Channel 9 Channel 13

• Decreased management traffic density can be seen on spectrum view when there’s no traffic in NW

From 3 ch to 4 ch

Less density 300ms beacons and no -b


Spectrum – Learning Center, Floor 1

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Less air utilization by mgmt traffic is well visible in

nighttime spectrum density


Spectrum – Learning Center, Floor 1

Zoom in (Sunday – Tuesday, Hourly average)

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• Decreased management traffic density can be seen on spectrum view when there’s no traffic in NW


Clean between channels. No “always on”

wideband interferers Significant non-WLAN interference during

daytime


Ground floor, after 4 channel plan

• 4 channels on average fit in well

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Floor 1, after 4 channel plan

• 4 channels on average fit in well

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TRAFFIC VOLUME PASSIVE AIR CAPTURES

ABSOLUTE VOLUMES TREND INDICATIVE ONLY

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Uplink data volume

• Floor 1: Overall and 2.4 GHz uplink data volumes seem to increase based on air traffic captures (may be temporary)

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Downlink data volume

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Number of clients/AP

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Number of clients/AP, Ground floor

• 2.4 GHz high peak values come down

• 5 GHz user counts seemed to increase until 6/6

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2.4 GHz 5 GHz

AP/HOURLY AVERAGE AP/HOURLY AVERAGE


Number of clients/AP, floor 1

• 2.4 GHz high peak values come down

• 5 GHz user counts seemed to increase until 6/6

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2.4 GHz 5 GHz

AP/HOURLY AVERAGE AP/HOURLY AVERAGE


After three changes • Significant improvements have been achieved already, rough values…

– Downlink throughput, up to 160% improvement

– Uplink throughput , up to 400% improvement

– HTTP throughput >60%

– Packet loss, 60% improvement

– Jitter, 50% improvement

– Latency, 30% improvement

– Retries 20-80% improvement

• Especially 1st floor 5 GHz performance has improved very much

• Actual used AP power levels may not have been the ones controller log showed? Resetting and fixing them seemed to increase power levels even though that was not expected based on the log displayed and manually set values

• 2.4 GHz channel plan is still slightly mixed in the surrounding (3 ch plan vrs 4 ch)

• Load is more evenly distributed

• 2.4 GHz need still some improvements to handle higher interference

• 2.4 GHz probe response load is still significant. Setting higher minimum SNR limit for AP to respond would probably help

• 5 GHz can be further improved with more channels and HT40

61


Optimization next

Done

• 5/29 4-channel plan on 2.4 GHz (Learning Center floors 0, 1, 2)

• 6/3 Beacon interval to 300 milliseconds

• 6/3 Remove 802.11b support completely and disable MCS 0, 8 and 16

• 6/6 Adjust AP radio power levels on both bands, set fixed levels

Next planned

• 6/11 Complete campus 4-channel plan on 2.4 GHz

• 6/11 Add more channels to 5 GHz plan (Learning Center)

Other TBD

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BACKGROUND INFORMATION ON

7SIGNAL EYE BEAM STEERING

TECHNOLOGY

63


Powerfull beam steering expands coverage and enables

accurate passive and end-to-end measurements Attenuates signals and

interference from other

directions, enables

accurate active and

passive tests

Amplifies signals

from target direction,

enables longer range

of operation

= Access Point

= Omni directional device

= 7signal Eye with directional antenna array

Omni directional operation,

no signal directivity in

this direction at all,

smaller coverage area

No interference/signal

suppression from other

directions, active tests distorted

by signals from other access

points and clients

7signal Eye Omni directional antenna

steerable

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7signal Beam Steering vrs Omni-directional antenna,

Side view from one floor in a multifloor building

Concrete floor

Concrete floor

Concrete floor

Concrete floor

Strong directivity also in vertical

direction, attenuates signals from

upstairs and downstairs and

reduces reflections in active tests

Omni-directinal antennas typically

have limited 2-4 dB directivity in

vertical direction. Picks up easier

interference from other floors

7signal Eye Omni directional antenna

Floor 1 Floor 1

= Access Point

= Omni directional sensor (WIDPS or other)

= 7signal Eye with directional antenna array

8deg. down tilted beam direction

8deg. down tilted beam direction Max gain directly

sideways towards other APs


7signal beam steering technology simulates

moving the measurement points closer to AP

Changing the beam while measuring APs at

different directions has similar impact as if

the test was made closer to AP with a

device with omni-directional antenna

steerable

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7signal Eye RF technology

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• 7signal Eye units utilize high performance patch antennas and low noise amplifiers in receiver chain to maximize receive sensitivity and make accurate active measurements

• Each patch antenna element has 7.5 dB gain, front back ratio 15-20 dB and -3dB bandwidth of 60-75%

• At the setup phase the best antenna is selected for each AP. From there on, automation uses always the same antenna for measuring an AP and metric’s related to that AP. This provides consistent data.

• This approach allows low amount of sensors and consistent passive and active performance trending measurements over time

Laptop USB adapter Omni-antenna. No directivity

“Standard” AP dipole omni antenna. No horizontal directivity

7signal Eye has an array of seven high gain patch antennas each with 7.5 dB vertical and horizontal gain at each direction separately. In additional low noise amplifiers for lowering receiver noise figure.

Advanced omni AP antenna has vertical gain but no horizontal directivity. No gain down tilt. In open space, antenna gain points directly towards other APs, not towards clients.

5 GHz

2.4 GHz


Gain patterns for one patch antenna individually

horizontal rotation, vertical polarization

2.4 GHz band

68

5 GHz band

Front-back Ratio >20 dB

Front-back Ratio >20 dB

-3 dB BW 60-75%

-3 dB BW 60-75%

22dB

28dB

21dB

32dB


Sounds cool?

Contact 7signal to make your WLAN perform!

www.7signal.com

[email protected]

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.

69

wlan performance optimization at avans university of applied sciences

Technology

following change

network level averages

impact of previous change

network performance

areaband averages

daily averages vrs bandarea

network configuration

daily averages vrs ap