7signal PoC AvansUoAS

WLAN performance baseline report

Avans University of Applied

Sciences, Netherlands 7signal Sapphire Trial

Baseline Report

March 21st, 2013


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.

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Eye Location: Floor 1 –Learning Center

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1

4 5

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7signal Eye

First Floor:


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• 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


2.4 GHZ BAND

END-TO-END PERFORMANCE

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2.4 GHz Attach Success Rate (Daily Average)

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• 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


2.4 GHz Attach Success Rate (One Week, hourly)

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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)


2.4 GHz Downlink Throughputs, daily

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• Daily average values are on acceptable level

Weekend


2.4 GHz Downlink Throughputs, hourly

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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


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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


2.4 GHz Uplink Throughputs, daily

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• Daily average values mostly on acceptable level

Weekend


2.4 GHz Uplink Throughputs, hourly

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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


2.4 GHz Uplink Throughput (2 Days), hourly

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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


2.4 GHz VoIP MOS Downlink Quality

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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


2.4 GHz VoIP MOS Uplink Quality

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Target level for MOS 3.6

Uplink MOS declines clearly declines on busy hours

• During the day time, hourly average thoughputs

degrade significantly


2.4 GHz Downlink Jitter

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• Jitter increases significantly with the load


2.4 GHz Uplink Jitter

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• Jitter increases significantly with the load

• Uplink increases more than downlink


2.4 GHz Downlink Packet Loss

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Target level 0.5%

• Packet loss increases significantly with the load


2.4 GHz Uplink Packet Loss

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Target level 0.5%

• Packet loss increases significantly with the load

• Uplink packet loss higher than downlink


2.4 GHz Latency

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• Latency increases significantly with the load

Target level 50ms


2.4 GHZ

DATA RATES AND RETRIES

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2.4 GHz – Downlink Data Rates in Synthetic Eye tests

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• 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


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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.


AP 1076 2.4 GHz data rate usage

Downlink (AP to client)

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• Low datarate usage from AP to clients

Undesirable low codecs


AP 1076 2.4 GHz data rate usage

Uplink (Client to AP)

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• Low datarate usage from clients to AP

Undesirable low codecs


2.4 GHz AP Retransmissions towards clients

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Undesired behavior

• High amount of retries reduce network capacity and daytime throughput

10% limit for data traffic


2.4 GHz Client Retransmissions towards AP

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Undesired behavior

10% limit for data traffic

• High amount of retries reduce network capacity and daytime throughput


2.4 GHz Eye Retransmissions in Synthetic Tests, hourly

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• High amount of retries in active tests


SPECTRUM AND

INTERFERENCE

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2.4 GHz Spectrum Graph

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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


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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)


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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


RADIO ENVIROMENT,

CONFIGURATION AND

UTILIZATION

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Radio channels at 2.4 Band

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Well organized 1-6-11 channel plan. No adjancent channel interference from other APs


Channel allocation and changes

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• No channel changes over the measurement period


2.4 GHz Number of SSID/MAC–pairs per channel

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• Rather well balanced 3 channel plan


Number of Clients in ”Eduroam” 2.4 GHz APs

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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


2.4 GHz WLAN Traffic Utilization

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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

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


SUMMARY AND

CONCLUSIONS

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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

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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

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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

[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. More information on Avans results will be also posted to 7signal blog.

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Technology

7signal PoC AvansUoAS