Gigabit WiFi: Utilising 802.11ac on Campus Considerations ... · Gigabit WiFi: Utilising 802.11ac...

MERU PROPRIETARY INFORMATION. © Copyright 2013. Meru Networks, Inc. All rights reserved.

Gigabit WiFi: Utilising 802.11ac on Campus

Considerations and Benefits

Consulting Systems Engineer, UK & Ireland

Paul Lambert


What’s in the 802.11ac Standard

• Very High Throughput (VHT) - up to 10x compared

with11n

– Wider channels: 80MHz, 160MHz, 80+80MHz (4X)

– New modulation: 256-QAM (1.3X)

– More MIMO streams: up to 8 (2X)

• Well defined Beam Forming

• Multi-User-MIMO (MU-MIMO)

3

802.11ac Standard Highlights


Data Rates in 802.11ac

4

20MHz 40MHz 80MHz 160MHz

1 stream 86.7 200 433.3 866.7

2 streams 173.3 400 866.7 1733.3

3 streams 288.9 600 1300 2340

4 streams 346.7 800 1733.3 3466.7

5 streams 433.3 1000 2166.7 4333.3

6 streams 577.8 1200 2340 5200

7 streams 606.7 1400 3033.3 4095

8 streams 693.3 1600 3466.7 6933.3

Expected in the first generation of silicon

Rates in Mbps

802.11ac Data Rate Matrix


DFS

Not allowed in

Europe

Wider channels: 80Mhz and 160Mhz

5

Available Channels for 802.11ac

48

IEEE channel #

20 MHz

40 MHz

80 MHz

5170 MHz

5330 MHz

5490 MHz

5730 MHz

5735 MHz

5835 MHz

160 MHz

36

40

44

60

52

64

116

56

136

132

124

120

108

100

104

128

112

165

161

157

140

153

Weather

radar Not allowed

in North

America

149

144

Dynamic Frequency Selection

Using DFS Channels Without DFS Channels

Channel Size US Europe US Europe

40 MHz 8 9 4 2

80 MHz 4 5 2 1

160 MHz 1 2


Standard Bandwidth Spatial

Streams PHY Data Rate Real Throughput

802.11a 20 MHz 1 54 Mbps 24 Mbps

802.11n 20 MHz 1 65Mbps 46 Mbps

802.11n 40 MHz 2 300 Mbps 210 Mbps

802.11n 40 MHz 3 450 Mbps 320 Mbps

802.11ac Phase I 80 MHz 1 293Mbps 210 Mbps

802.11ac Phase I 80 MHz 2 867 Mbps 610 Mbps

802.11ac Phase I 80 MHz 3 1300 Mbps 910 Mbps

802.11ac Phase II 160MHz 1 867 Mbps 610 Mbps

802.11ac Phase II 160 MHz 2 1730 Mbps 1200 Mbps

802.11ac Phase II 160 MHz 3 2600 Mbps 1800 Mbps

802.11ac Phase II 160 MHz 8* 6933 Mbps 4900 Mbps

* There are no commercial implementations that use more than 3 spatial streams

Data Rate Table


Thank You

Power and space challenges are still the same

• Don’t expect more than 3 data streams soon (-)

• Higher rates available at ranges closer to the AP (-)

• Higher throughput efficiency mean less time (power) spent for transmit (+)

• Users will still observe greater net throughput (+)

Rate and Range


Questions?

Predicted Uptake


Beamforming

9

• Introduced in 802.11n

• 802.11n had many options – no vendor implemented it

• 802.11ac uses a single standard for beam forming


• By changing time (phase) of 3 transmitters, 802.11ac AP’s can create

a “constructive interference” transmit beam-forming waveform (TxBF)

and generate a stronger signal that clients can hear better.

10

AP 3rd Stream

2nd Stream

1st Stream

AP

Destructive Interference, when three

streams of RF energy cancel each other

11ac

AP 3rd Stream

2nd Stream

1st Stream

Constructive Interference, when three

streams of RF energy stack up each other

11ac

AP

Without

Beam-

forming

With

Beam-

forming

Beamforming


A standard 3x3:3SS 802.11n

AP effective coverage at

different modulation rates

802.11n 64 QAM coverage

Top rate @ 450 Mbps


Top rate @ 180 Mbps


Top rate @ 450 Mbps


Top rate @ 180 Mbps

GbE

Zone

802.11ac 256QAM 64 QAM

Top rate @ 1330 Mbps

Where can

I access

my Wi-Fi?

User is outside of RF

coverage zone with

lowest RX Z(e.g. -90

dBm receiving

sensitivity)

User is within RF coverage

zone with due to reconstructed

radio coverage (due to different

phase)

Beamforming


Multi-User MIMO

• Allows a sophisticated AP (#Antennas > #Streams) to maintain high throughput even when the clients are simple (smartphones, tablets, etc…)

• Up to four simultaneous clients, each with one or more antennas, transmit or receive independent data streams

• Needs MU-MIMO beam forming support

• Provides better channel reuse in single channel, enables high client density – 4 x density

• Expected only in the second generation of silicon

12


• Survey/Plan for 5GHz coverage

– Old AP placements are probably based on old requirements

– Higher signal strength requirement for 256QAM data-rates

• 40 or 80MHz Support

– Highest data rates are only available with 80MHz channels

– Not all vendors are recommending 80MHz channel widths due to

architectural constraints

• 802.3af/at PoE PD Support

– Some solutions require 802.3at PoE+ to operate at full performance

• Multiple GigE ports per AP

– Worth considering provision, but not a must-have

– Possible more benefit for resilience than performance

13

802.11ac Design Considerations

MERU PROPRIETARY INFORMATION. © Copyright 2013. Meru Networks, Inc. All rights reserved. 14

802.11ac Benefits

• Higher data-rates than 802.11n

– Gen 1 802.11ac AP’s offering 1.3Gbps vs 450Mbps on 11n

• Greater density

– Higher data-rates mean clients need less time to complete their data

transfers. Leaves more space for more clients

– Gen 2 AP’s will add MU-MIMO capability

• Better ‘n’ than ‘n’

– Testing from multiple vendors has shown an increase in performance in

802.11n chipsets when used on 802.11ac infrastructure - no need to wait

for benefits

• Power consumption benefits on client devices

– More efficient transmissions lead to lower battery requirements


Bonjour! A friendly greeting, or death to your network?

MERU PROPRIETARY INFORMATION. © Copyright 2013. Meru Networks, Inc. All rights reserved. MERU PROPRIETARY INFORMATION. © Copyright 2013. Meru Networks, Inc. All rights reserved.

Bonjour - Many Challenges

• Advertisement Problems – Bonjour is local only, designed for home use

– Others use multicast

• Scalability Issues – Bonjour doesn’t scale due to

• Location Challenges – Which services are relevant

• Policy and Control – Who should advertise services?

– Who should learn about services?


Service Control in Action (Bonjour)

Discover Consolidate Distribute Advertise

Po

licy

Po

licy

POLICY CONTROLLED SERVICE DISCOVERY & ADVERTISEMENT


Service Control – Use Case

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Administration Building Liberal Arts Building

ESSID: student

ESSID: staff

vlan 700 Vlan 600


Service Control - Discovery

19


ESSID: student

ESSID: staff

vlan 700 Vlan 600

Global Service Discovery List

Liberal Arts - Apple TV

Liberal Arts - Printer

Admin Bldg - Printer


Service Control Policy - Faculty

20


ESSID: student

ESSID: staff

vlan 700 Vlan 600





Service Control Policy - Student

21


ESSID: student

ESSID: staff

vlan 700 Vlan 600

Global Service Discovery List





Questions???


Thank You

Gigabit WiFi: Utilising 802.11ac on Campus Considerations ... · Gigabit WiFi: Utilising 802.11ac...

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