Technology for High Performance WLANs

Serving The Needs Of

Higher Education

2

Agenda

• Meru Networks – Our Mission

• Why 802.11 WLANs require QoS for Voice and Data

• Meru’s QoS Architecture

• Comparing QoS Solutions

• Converged Network Case Study

• High Performance b/g Network Co-Existence

• Location Based Services

3

Our Mission

Design and manufacture 3rd generation WLAN (Wi-Fi ) solutions for voice & data

Comprehensive SecurityComprehensive Security

Easy Deployment & ManagementEasy Deployment & Management

Transparent MobilityTransparent Mobility

High DensityHigh Density

QoSQoS

Zero Configuration

Multi-layers

5x Number of Voice Calls

5x Number of Active Users

0 Loss - Handoff

High Performance:With

Meru Air Traffic Control Technology

4

Meru Wireless LAN Infrastructure Products

Floor 2Floor 2

Floor 1Floor 1

Data CenterData Center

L2 / L3Backbone

Virtual APVirtual AP

AP

AP

Meru Controller

Meru AP

Coordinated Access Points► Over-the-Air QoS► Contention management

Controller► Centralized appliance for

management and security► RF Interference Management► Built-in application

Flow-Detectors e.g. SIP, H.323, Cisco Skinny, Spectralink SVP

► Location Services

5

Wireless LAN Evolution

Number of Clients and Coverage

Applications

Products /Technology

• Email, Web

• Stand-aloneAccess Points

Stand Alone Multi-site

• Email, Web from different locations

• Centralized security and management

• High Density• Application QoS• Transparent mobility• Full network integration

• Voice and Data• Business applications• Primary connectivity• Video emerging

Pervasive

6

Enterprise WLAN Product Evolution

Generation 1 + Central ManagementSecurity

2000-011st Generation

2002-32nd Generation

2003-43rd Generation

Aggregated AP’sCentral Switch/

ApplianceStand-alone APs

Cisco 1200+SWANSymbol

Aruba, Trapeze, Airespace …

Meru

Generation 2 + RF IntelligenceHigh DensityQoSZero Handoff

Cisco 350ProximLinksys

Basic Connectivity

Ser

vice

s /

Sca

le

Coordinated AP’sCentral Switch/

Appliance

7

University WLAN Requirements

High Density► Lecture halls, classrooms, memorial unions, etc

High Mobility► Students, faculty, visitors – constant movement

Data, Voice, and Video► Data today► Voice emerging – soft phones, dual mode cell phones► Video – lecture content, video presentations, etc.

Integrated Security► Student / faculty / guest security profiles► Integration with network access control► Location based security

8

WLAN Architectures

Medium & large enterprise

Scaleable, central management

Centralized intelligence

SOHO, Medium & large enterprise

Target Markets

Simple implementation for a few access points,

Centralized Management

Benefits

Stand alone APs, Centralized or Distributed

Management

Architecture

“Stand Alone” or Fat” AP “Thin” or “Fit” AP

LAN Switch WLAN Switch / Controller

Medium & large enterprise

RF coordination, simple deployment, scaleable,

central management

Overlay WLAN network, distributed intelligence,

centralized control

“Intelligent” AP

WLAN Switch / Controller

9

Key Requirements WLANs

SecuritySecurity

Easy Deployment & Management

Easy Deployment & Management

Transparent MobilityTransparent Mobility

High DensityHigh Density

QoSQoS Priority for Voice Calls, Video

Capacity for Active Users

Zero Loss Handoff

Air Traffic Control

Technology

With Standard WiFi Clients

Take Control of the Converged WLAN

Take Control of the Converged WLAN

10

Issues for Voice & Data over Wi-Fi

1. Unpredictable behavior over-the-air Random allocation of air time

2. Poor performance Low user density

Low number of voice calls, call quality

Handoff

3. Security

4. Difficult to install

5. Difficult to manage

11

802.11 Challenges for Voice & Data

The 4 fundamental problems that must be solved to achieve enterprise level performance for high density Voice and Data for Wi-Fi networks:

1. Single Cell Contention

2. Contention Across Cells

3. Jitter and Volatile Bandwidth Allocation

4. Slow Handoff

12

Problem 1: Contention within Single Cell

20

5

8

11

1 3

Baseband + Protocol Overhead

ContentionLoss

ContentionLoss

Today’s AP

Performance

Number of Active Users

To

tal

Ba

nd

wid

th a

t P

ea

k

(Mb

ps

)

• Multiple clients contend for the same shared medium

• While transmitting sender cannot listen for collisions

• As number of calls goes up, collisions increase

• Collisions cause clients to backoff

• Backoff slows down network

• Requires more than scheduling

S

R

I

I

I

Air = Shared Medium

13

5.5/11Mbps

CS

Rec

eive

Sig

nal

at

AP

1Mbps

Distance

Problem 2: Co-Channel Interference Across Multiple Cells

Cellsize

Collision Domain

InterferenceDomain

Interference Range Is Much Larger

Than Communications Range

Mbps

14

Problem 3: Jitter & Bandwidth Allocation

5.46 5.48 5.5 5.52 5.54 5.56Time (Sec)

Channel Access with Today’s 802.11 APChannel Access with Today’s 802.11 AP

2

6

4

8

10

12

5.36 5.38 5.4 5.445.42

As number of calls goes up:

• Random channel access by clients causes latency & jitter

• AP gets less bandwidth (only 1/nth of channel)

• Erratic, unfair access over short term intervals (completely starved 2 clients)

Cha

nnel

Throughput 1 AP + 20 Clients

15

Problem 4: Slow Handoff Across Cells

• Beacon and Probes to join available ESSID

• 802.11 Association and Authentication process

• 802.1X Authentication or any other type of security authentications (includes Radius or other AAA servers)

• IP address assignment

100ms – 1 sec between handoff

BSSID = A BSSID = B

01:00

16

Meru Networks - QoS Architecture

Application Flow Detection

Application Flow Detection

Global RF Resource Knowledge

Global RF Resource Knowledge

Admission ControlAdmission Control

Control Mechanismsin 802.11 Standard

Control Mechanismsin 802.11 Standard

Meru QoSAlgorithms

+

Global knowledge of interference and resource usage at AP’s including knowledge of clients

Time-based accounting, not bandwidth-based Inter-cell Coordination

Deep packet inspection for understanding resource requirements of Application (e.g. SIP/Codec)

Resource management

+

+

Virtual carrier sense for uplink reservation/QoS Contention-free periods and contention periods.

Per-flow SchedulingPer-flow Scheduling Uplink and Downlink accounting of packets /

expected packets Reservation-based QoS

+

17

Meru Networks - Air Traffic Control

Centralized Control- Global Policies- Global Coordination- Central RF Intelligence- App Flow Inspection

MERU MAC- Local Governance

- Dynamic QoS Flow Recognition- Distributed Rogue Detection & Mitigation

Performed in Controller

Performed in the Access Point

ContentionManagementAlgorithms

ContentionSuppression for

QoS Flow

Virtual MACfor

Zero Handoff

VoiceClientVoiceClient

18

Comparing Control of the AirHow Meru Delivers Over-the-Air QoS

Mgmt (Auth/Assoc/Probe)

Beaconing

Packet Fragmentation

Scheduling/Queuing

Lower MAC (CSMA/CA)

PHY

RF

Integrated

MAC/PHY

Access to the Lower MAC is critical to provide QoS

Decisions need to be made at microsecond level based on prior packet air conditions

Other AP’s queue packets asynchronously requiring decisions to be made several time intervals prior to transmission

Reference-

design APMeru AP(with

Meru MAC)

802.11

Phy/RF

Asynchronous Interface

Between SWAnd MAC/PHYSychronous

Interface

Meru AP Other APs

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Predictable channel access Predictable and low jitter Support for higher number of clients

5.56

AP

C6

C4

C8

C10

C12

5.36 5.38 5.4 5.44 5.46 5.48 5.5 5.52 5.545.42

Channel Access with Meru AP for QoS Flows

Time (Sec)

Application Flows with Over-the-Air QoS

Air Traffic Control - The Result

Meru AP

20

Meru Air Traffic Control Technology 5x More Users

20-25

Tot

al B

andw

idth

at

Pea

k (M

bps) 5

8

11

1

3

ContentionLoss

ContentionLoss

Today’s APPerformance

Meru AP Performance

Active Users Per AP

Today Meru

20-25

100+

5X5X

Number of Active Users

Peak Aggregate Throughput

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Generic Access Point + Standard Client

Meru AP +Standard Client

Meru Air Traffic Control Technology Over-The-Air QoS: 5X More Voice Calls

Converged Network - voiceand data on same channels

Data and voice typically on Separate channels/network

~20-30

~5-8

APWired QoS

Wired QoS

Standards-basedOver-the-Air

QoS AP

Voice

Quality

MOS Score

4.0+

Over-the-air QoS

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Meru Quality of Service - Results

Industry leading aggregate throughput at density

Predictable, uniformly fair throughput across all clients► Other AP’s erratic, unfair access over short term intervals completely starved 2

clients

4X less loss rate (2% - 2.5%)► Versus other AP’s 8% loss rate

Throughput 1 AP + 20 Clients Throughput 1 Meru AP + 20 Clients

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Meru Air Traffic Control Technology Results - Zero Loss Handoff

Meru WLAN

Virtual AP Architecture

No Handoff For Client

BSSID = M BSSID = M

00:00

100ms – 1 sec between handoff

Today’s WLAN

BSSID = A BSSID = B

01:00

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Meru Quality of Service - Summary

Works with all standard 802.11 Wi-Fi clients Fine grained upstream and downstream

over-the-air QoS with easy provisioning ► Voice flow detectors (SIP, H.323, Vocera, Spectralink,

Cisco)► Real-time highest priority

► Application QoS Rules ► Real-time, user-configurable rules

► Client Fairness► 8 priority queues► Optimized throughput with Meru Air Traffic Control algorithms

for predictable performance

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How Meru Over-the-Air QoS Compares to Others

Meru 802.11e / WMMToday’s AP’s /

“WLAN Switches”

Global RF Knowledge and Inter-cell Coordination

Yes -- --

Application Flow Detection and Classification

Yes (Dynamic) --Static ESSID-based or

Filters

Admission Control Yes -- --

Downlink (AP to Client)Reservation-based

True over-the air QoSLow-scale

Simple Priority of packets

Uplink (Client to AP)Reservation-based

True over-the air QoSLow-scale

With Client-side HW/SW--

Customer Case Study

27

Jackson Memorial Hospital A Meru Customer Success Story

Creating a Wireless LAN with better utilization across different applications is the right move for companies today. Enterprises require third generation Wireless LAN products with coordinated Access Points that permit greater scalability and centralized management. This will lead to a reduction in the overall costs of wireless infrastructure while improving performance.

Rachna Ahlawat, Principal Analyst, Gartner Inc.

”

“ Universityof Miami

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Inability to manage contention needed to support high density environments

Cannot operate on a single channel to avoid interference with outdoor AP

Unable to deliver over-the-air QoS needed for mission-critical applications

The Jackson Memorial Hospital Wi-Fi Challenge

An indoor WLAN solution that could reliably co-exist with its existing outdoor AP’s

Future-proof system to support data today and voice in the future.

Support for high user density and broad range of devices

Key RequirementsWhy Other Systems Fall

Short

29

Meru system seamlessly connected to existing wired Cisco switches and works with any standard 802.11 client (phone, pda, laptops)

Dynamic over-the-air QoS supports reliable data services today and high-performance voice and video in the future

Single Channel Deployment Leverage Existing Wired & Wireless Investments

MeruController

PBXVoceraSystem Server

Data CenterData Center

NetscreenSSL VPN

Outdoor AP

Outdoor

Laptops

VoceraBadges

Cisco Catalyst6500

Virtual APVirtual AP

WiFiPhones

PDAs

Tablet PCs

Laptops

Floor 2Floor 2

Floor 3Floor 3

Floor 4Floor 4

Floor 5Floor 5

Floor 6Floor 6

Floor 7Floor 7

Cisco CatalystSwitch

PAC Building

Meru AP

Cisco CatalystSwitch

Network Admin Building

High Performance b/g Network

Co-Existence

31

Why 802.11 b/g Co-Existence?

Backwards compatibility of b clients ► Large and growing installed base of b

clients (Millions) Utilize same AP infrastructure

► No new AP installations► No RF re-planning

Higher channel efficiency for g networks► Leverages the g network speed – 54 Mbps

32

The b/g Co-Existence Problems

Significant Co-Channel interference► Only 3 spectrally independent channels► Coverage required for high data rates

802.11b slows down g clients► g client throughput reduced by 50%+

33

802.11b Slows g Clients

b client preamble and header impact control and data periods for g clients

Significant reduction in data rate – greater than 50%

Preamble PLCP Data ACK

CTS

Preamble PLCP

Preamble PLCP

Pre

PLCP

Data Pre

PLCP

ACK

Pre

PLCP

Data Pre

PLCP

ACK

802.11b Only

802.11g Only

802.11g/b Carrier Sense Virtual Carrier Senseb Client

g Client

CCK

OFDM

> 2X micro sec.

X micro sec.

34

Concurrent High Performance

Separate 802.11b and 802.11g networks into different BSSIDs

► Logically isolate b and g clients Creates packet level interoperation

► Controlled channel access► g only window► b only window

Adaptively determine the window period► Protocol content► Flow-level info (upstream & downstream)► Number of b clients► Number of g clients

35

Deployment Architecture

Meru ControllerDHCP Server

RADIUS Server

Routed Core

Virtual Wireless Subnet

Meru AP to controller tunnels established over routed infrastructure

Separate BSSIDs for b and g clients

AP’s can advertise each b and g network (2 BSSIDs)

APs control channel access based on required b and g resources

APs utilize adaptive control algorithms to determine window period

AP APAP802.11b ESSID #1

802.11g ESSID #2

b b

ggg

36

Meru Eliminates Trade-Off Between Backward Compatibility and g Throughput

UDPg (with b clients present)

~14.8

~22.6

Vendor C Meru

~10.3

~15.8

Meru

~3.4

~10.1

Meru

TCP1g

TCP1g +1bg client perf.

Source: Meru Lab Tests

Vendor C Vendor C

37

Summary

Breakthrough Air Traffic Control Technology Delivers Concurrent 802.11b and 802.11g with High Performance

► Simplify 802.11g deployment – no new APs

► Highest 802.11g throughput in mixed b/g networks

► Leverage deployed 802.11b clients

► Eliminate user performance compromise

Location Based Services

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Planning / Site Survey – “Snap Shot”

Create Network Plan:► Upload map (.jpg or .png file, no

need for CAD drawings)► Draw walls and other obstacles

(optional)► Place access points on the map► Simulate the network coverage

Perform Site Survey► Upload map (.jpg or .png file, no need for CAD drawings)► Deploy the APs as per plan Survey the site - Measure the coverage► Fix the coverage holes if any by adding APs or adjusting antennas

40

RF Visualization – “Real-Time”

• Visualize coverage based on signal strength, data rate, • Determine which areas support given ESSID, or channels• Visualize network performance and coverage holes

Visualize Coverage

41

Location Tracking Applications

Real-time location of Rogues, clients► Pinpoint rogue device (AP or client) to specific location (in a cubicle, in

the hallway, outside the building)► Allow connectivity only when client at specific location (e.g. inside

building) Real-time capacity management/troubleshooting

► Identify relevant portion of a network for capacity adjustment or troubleshooting based on caller’s location

Mobile asset tracking► Locate critical equipment or assets in hospital, manufacturing, retail

environments E-911 support

► Meet regulatory requirements for calls that require emergency dispatch

42

Location Tracking Technology

Traditional approaches:► Closest AP – find the AP that hears a signal the loudest

► Very coarse granularity (point in 60’x60’ or 3600 sq ft area)

► Triangulation – overlap coverage from 3 different APs► Granularity of ~ 30’► Challenges: Reflection, attenuation, multi-path

► RF-Fingerprinting – predict signal strength at every grid point, and match against it

► Hours of RF signature training ( ‘can you hear me now?’ approach)

► Granularity of ~10’

43

Summary

Over-the Air QoS is required for Converged WLAN networks

Breakthrough Technology Delivers Concurrent 802.11b and 802.11g with High Performance

“Stay tuned” for Location based WLAN services

Thank You

Nate WalkerDirector, Product Managementnwalker@merunetworks.com