1 © 2000, cisco systems, inc. wireless lan solution & deployment tjie seng, njauw

1© 2000, Cisco Systems, Inc.

Wireless LAN Solution & Deployment

Tjie Seng, Njauw


The Paradigm ShiftThe Paradigm ShiftThe Paradigm ShiftThe Paradigm Shift

Fixed Communications

Mobile Communications



Fixed Work Area

Work where you want!



Tethered NetworkConnection

Wireless Network ConnectivityWireless LAN Products


Radio Frequency Technologies WLANs Product Categories Standards Based Technology

What is a Wireless LAN?


Radio Frequency TechnologiesRadio Frequency TechnologiesRadio Frequency TechnologiesRadio Frequency Technologies

Wireless DataNetworks

Broadband PCSBroadband PCSMetricomMetricom

Local WideCoverage Area

SatelliteSatellite

Spread SpectrumWireless

LANs

Spread SpectrumWireless

LANs

Circuit & Packet DataCellular, CDPD, RAM, ARDIS

Circuit & Packet DataCellular, CDPD, RAM, ARDIS

Narrowband PCSNarrowband PCS

InfraredWireless

LANs

InfraredWireless

LANs

Narrow BandWireless LANsNarrow Band

Wireless LANs

Wireless LAN 802.11b

Dat

a R

ates

9.6 Kbps

19.6 Kbps

56 Kbps

1 Mbps

2 Mbps

4 Mbps

10 Mbps


License Free ISM BandLicense Free ISM BandLicense Free ISM BandLicense Free ISM Band

ExtremelyLow

VeryLow

Low Medium High VeryHigh

UltraHigh

SuperHigh

Infrared VisibleLight

Ultra-violet

X-Rays

AudioAM Broadcast

Short Wave Radio FM BroadcastTelevision Infrared wireless LAN

Cellular (840MHz)NPCS (1.9GHz)

902-928 MHz26 MHz

Older Product

5 GHz(IEEE 802.11A)

HyperLANHyperLAN2

Future Technology

2.4 – 2.4835 GHz83.5 MHz

(IEEE 802.11B)Current Product


Binary phase shift keyed (BPSK)

• BPSK uses one phase to represent a binary 1 and another to represent a binary 0 for a total of two bits of binary data. This is utilized to transmit data at 1Mbps.

Quadrature phase shift keying (QPSK).

• With QPSK, the carrier undergoes four changes in phase and can thus represent four binary bits of data. This is utilized to transmit data at 2 Mbps.

Complementary code keying (CCK)

• CCK uses a complex set of functions known as complementary codes to send more data.

• One of the advantages of CCK over similar modulation techniques is that it suffers less from multipath distortion. This is utilized to transmit data at 5.5 and 11Mbps.

Radio ModulationRadio Modulation


2 Mbps DSSS350 feet radius

In Building WLANsIn Building WLANsIn Building WLANsIn Building WLANs

5.5 Mbps DSSS 175 feet radius

11 Mbps DSSS 100 feet radius

Average 802.11bAccess Point Range


Direct Sequence ModulationDirect Sequence Modulation

• Each data bit becomes a string of chips (chipping sequence) transmitted in parallel across a wide frequency range

• Minimum chip rate per the FCC is 10 chips for 1 and 2MB (BPSK/QPSK) and 8 chips for 11Mb (CCK) data rates.

If the data bit was: 1001

Chipping code is : 1=00110011011 0=11001100100

Transmitted data would be:

00110011011 11001100100 11001100100 00110011011

1 0 0 1


Channels- 802.11 DSChannels- 802.11 DS

• (11) 22 MHz wide stationary channels

• x “chips per bit”, means each bit sent redundantly

• 11 Mbps data rate

• 3 non-overlapping channels

• 3 Access Points can occupy same area

1 2 3 4 5 6 7 8 9 10 112400

2472241212 13


Scalability With Direct SequenceScalability With Direct Sequence

Blue= 11Mb

Green=11Mb

Red=11Mb

Total Bandwidth=33MB!!!


Wireless Capacity per Cell

0

5

10

15

20

25

30

35

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31

Number of Access Points

Mb

ps

Cap

acit

y

DS-2Mb

DS-11Mb

ScalabilityScalability


Power Level & Cell SizePower Level & Cell Size


In-Building Design ConsiderationsIn-Building Design Considerations

• 200 Users on the Floor

• Reduce Power - 5mW

• 18 Access Points

• 11 Users per AP of shared bandwidth

1

6

11

1

11 6

6

11

1

1

6

11

1

11

6

6

11

1

• 200 Users on the Floor

• Full Antenna Power – 30mW

• Max 3 Access Points

• 67 Users per AP of shared bandwidth

1 6 11


WLAN Product CategoriesWLAN Product CategoriesWLAN Product CategoriesWLAN Product Categories

In-Building WLANs

Building-to-Building WLANS


In-Building WLANIn-Building WLANComponentsComponents


Internet

Ethernet Backbone




Internet

Ethernet Backbone

Overlapping “cells” Overlapping “cells” Allow for RoamingAllow for Roaming




Internet

Ethernet Backbone


Inline Power Inline Power

Source operating current from the Ethernet port, over the Cat 5 cable.

Line power configuration is compliant with all of Cisco’s line power enabled devices such as switches and line power patch panels.

Distances up to 100 meters

Call Manager Server

VoIP Phone

AP Switch

Powered CAT5


Load BalancingLoad Balancing

• AP’s configured for load sharing use different RF channels in coverage area

• Policy can be based on number of users, bit error rate, or signal strength

Channel 1

Channel 6


Hot StandbyHot Standby

• AP’s co-located for hot standby use SAME RF channel in coverage area

• Standby AP acts as probe for monitoring and management

Active Standby

Channel X

Channel X


Security ConsiderationsSecurity ConsiderationsSecurity ConsiderationsSecurity Considerations

(*#&$(*#&$*( #(*&

$*(#$#)($__%#

#$#%

40-Bit

128-Bit

Encryption or WEP


Centralized User-Based Centralized User-Based AuthenticationAuthentication

AuthenticatorAuthenticator(e.g. Access (e.g. Access

Point, Catalyst Point, Catalyst Switch(?))Switch(?))SupplicantSupplicant

Semi-Public Semi-Public Network /Network /Enterprise EdgeEnterprise Edge

AuthenticationAuthenticationServerServer

RADIUS

EAP Over Wireless/LAN

EAP Over Wireless/LAN

(EAPOW/EAPOL)

(EAPOW/EAPOL)

EAP Over

EAP Over

RADIUSRADIUS

Extended Enterprise(Branch Office, Home, etc.)

EnterpriseIntranet


ManageabilityManageabilityManageabilityManageability

Site SurveySite Survey

Signal Strength

Signal Quality

•Diagnostic Utilities •Simple and Graphical •Minimizes Helpdesk Calls


In Building Site SurveyIn Building Site Survey


•Decreases Implementation Costs A Fraction the Cost of Trenching

•High Speed ConnectionsGreater Bandwidth than T1 Lines

•Eliminates Recurring ChargesNo Monthly Leased Line Fees

•Reduces Installation DelaysNo Right of Way or Permits Required, Installation in an Afternoon

•Makes Physical Barriers IrrelevantBypass Lakes, Rivers, Freeways, Railroads

Wireless BridgesWireless BridgesWireless BridgesWireless Bridges


Wireless AntennasWireless AntennasBridgesBridges

Patch Wall Mast MountHigh Gain

Mast Mount Yagi Mast Solid Dish

Type

Gain

ApproximateRange at 2 Mbps

ApproximateRange at 11 Mbps

Cable Length

Directional

Beam Width

8 dBi

60 H55 V

2.0 Miles

3390’

3’

Omni

5.2 dBi

360 H75 V

5000’

1580’

3’

Omni

12 dBi

360 H7 V

4.6 Miles

1.4 Miles

1’

Directional

13.5 dBi

6.5 Miles

2 Miles

1.5’

30 H25 V

Directional

21 dBi

25 Miles

11.5 Miles

2’

12.4 H12.4 V


0 to 25 miles(line of sight)

Ethernet

Bridge

OptionalAntenna

Building A Building B

OptionalAntenna

Point-to-Point ConfigurationPoint-to-Point Configuration


Bridge

Bridge

PCI Card

MC Hub

Bridge-Bridge, Bridge-ClientBridge-Bridge, Bridge-Client


Outdoor Path ConsiderationsOutdoor Path Considerations

• Radio line of sight

• Earth bulge

• Fresnel Zone

• Antenna and cabling

• Data rate


Bridge Application: Bridge Application: Wireless Campus linkWireless Campus link

U N I V E R S I T YU N I V E R S I T Y

Channel #11

Channel #6

Channel #1


IEEE 802.11 IEEE 802.11 A Move Toward Standardization!A Move Toward Standardization!

• A very high-performance WLAN system Efficient MAC and high-quality radio

802.11 products perform better thanproprietary systems

Client interoperability • WEP standard privacy and authentication

• Standards-based migration path for system growth

• The IEEE 802.11 (July 1997) for 1 and 2Mb DSSS

• The IEEE802.11b (Sept 1999) for 11Mb DSSS


WI-FI CertificationWI-FI Certification

• WECA certifies Interoperability between products.

• This provides assurance to customers of migration and integration options.

• Certified products can be found at http://www.wirelessethernet.org/


Soo… What’s Next..Soo… What’s Next..


Internet Mobile OfficeInternet Mobile Office

• Broadband solution for the mobile business professional that combines all of the following:

Wired and wireless connectivity

Broadband speeds when on the move

Access to critical business applications

Secure, end-to-end VPN access

Nationwide and international coverage

Consolidated billing across service providers

Access to localized content


TownTownClubsClubs

Airline LoungesAirline Airline

LoungesLounges

HotelsHotelsHotels

Other PublicVenues

Other PublicOther PublicVenuesVenues

ConventionCenters

ConventionConventionCentersCenters

CafesCafesCafes

AirportsAirports

CommercialBuildings

CommercialCommercialBuildingsBuildings

TownTownClubsClubs

Airline LoungesAirline Airline

LoungesLounges

HotelsHotelsHotels

Other PublicVenues

Other PublicOther PublicVenuesVenues

ConventionCenters

ConventionConventionCentersCenters

CafesCafesCafes

AirportsAirports

CommercialBuildings

CommercialCommercialBuildingsBuildings

Bringing Mobile Offices to Mobile Bringing Mobile Offices to Mobile ProfessionalsProfessionals

Enterprise

Customers


Wireless Mobile Business Professionals Public Spaces

InternetT1/T3

Enterprise Network

T1/T3Airport / Public Spaces

Switch

Router

Firewall

VPNConcentrator

Service Subscriber Gateway

Settlement System

Server

Hotels

T1/T3

Wireless 802.11b Access Point

Wireless 802.11b Clients w/ VPN Client

Service Subscriber Gateway

Switch

T1/T3

Wireless 802.11b Access Point

1 © 2000, cisco systems, inc. wireless lan solution & deployment tjie seng, njauw

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