designing wireless

7/29/2019 designing wireless

1/28

1 2002, Cisco Systems, Inc. All rights reserved.5733_07_2002_c1

Networking ProfessionalsOnline TechTalkDesigning and Deploying

Higher-Speed Wireless LANs


2/28


Networking ProfessionalsOnline TechTalk

Bruce AlexanderTechnical Marketing Manager

Byron HendersonDirector, Enterprise Product Marketing


3/28


Agenda

Wireless LAN Technologies to Consider

Rules and Regulations Regarding Wireless LAN

Designing 802.11a Wireless LANsLimitations

Designing Dual Band Wireless LANs

Considerations for Migrating to FutureTechnologies

Applications for Dual Band Systems Update on Wireless LAN IEEE Standards

Managing WLANs


4/28


The Wireless BAGThree Technologies

The Laws of Radio Dynamics:

Higher Data Rates = Shorter Transmission RangeHigher Power Output = Increased Range, but Lower Battery LifeHigher Frequency Radios = Higher Data Rates Shorter Ranges

802.11b 802.11a 802.11g

2.4GHz 5GHz 2.4GHz

Worldwide US/AP Worldwide

11Mbps 54Mbps 54Mbps

FrequencyBand

Availability

MaximumData Rate

OtherServices

(Interference)

Cordless PhonesMicrowave Ovens

Wireless VideoBluetooth Devices

Cordless PhonesMicrowave Ovens

Wireless VideoBluetooth Devices

HyperLAN

Devices


5/28


802.11b Rules

Channels

FCC/US/Canada 11

ETSI 13

Japan 14

Only 3non-overlapping

Power levels

FCC/US/Canada 36dBm EIRP

ETSI- 20dBm EIRP

External antennas

FCC/USUnique connector

Maintain legal EIRP levels

Virtually approved for worldwide use

1 2 3 4 5 6 7 8 9 10 112400 2483


6/28


802.11a UNII1 and UNII 2 (WLAN) Rules(FCC/US)

U-NII 1: 5.15GHz to5.25GHz

Indoor only, 40mW maxw/6dBi integrated antenna

Four 802.11a Channels

U-NII 2: 5.25GHz to5.35GHz

250mW max with variety ofantennas

Four 802.11a channels

802.11a WLAN productsMost combine INII1 and UNII2

Provides 8 channels

Limits antennas tointegrated ONLY

ConductedPower

5.15 5.355GHz

U-NIIBand

5.25

4 Ch4 Ch

40mW 250mW

UNII-1 UNII-2

(16dBm) (24dBm)

EIRP

Antenna Gain 6dBi 6dBi

22dBm 30dBm1 W158mW


7/28


Range Comparisons

11 Mbps 140 Ft

5.5 Mbps 180 Ft

2 Mbps 250 Ft

1 Mbps 350 Ft

54 Mbps @4060 FtRadius

48 Mbps @ 7090 Ft

36 Mbps @ 90110 Ft

24 Mbps @ 110125 Ft

18 Mbps @ 125135 Ft

12 Mbps @ 135145 Ft

9 Mbps @145155 Ft

6 Mbps @ 155165 Ft

5Ghz/40mW

Ranges Using 2.2dBi Dipole Antenna onAP, and Standard PC Card Style Radio

2.4Ghz/100mW


8/28


802.11g Rules and Estimated Ranges

Uses same band, channelscheme, bandwidth andpower levels as 802.11b

For 1, 2, 5.5 and 11Mb,identical to 802.11b

modulation

Same antenna schemes as802.11b

Should be permitted in anycountry where 802.11b is

permitted Range will be less at higher

data rates

Remote antennas permitted

11Mb(Same as 802.11b)

54Mb(802.11g)


9/28


Antenna Options 802.11b/g

The AP1200 providesdual RP-TNC

connectors for 2.4GHzdiversity antennas

This provides a greatflexibility for antennaselection, AP

placement, and rangeand coverage variations

802.11b/g

Any Approved 2.4GHzAntenna Can Be Connected

Remotely Here


10/28


Antenna Options 802.11a

The AP1200 5GHzradio module providesan integrated antenna

module

Based on position ofthe antenna withrespect to the AP:

2dBi diversity dipole

6dBi diversity patch

6dBi

2dBi


11/28


802.11a Mounting Issues

Integrated antennas limitmounting locations

May not be able to provideout of sight locations

Floor/Roofsupport

Drop

Ceiling

Heat/AirConditioning

Ducts

LightningFixtures

5GHz

Antenna 2.4GHz Antennas

Typical above Ceiling Obstacles


12/28


Other Issues for Comparing b/a/g

Power consumption

802.11a is typically MUCH higherin power consumption today

Much shorter battery life on

portable devices Interface architecture

54Mb requires higherbus speeds

PCMCIA not adequate

PCI or card bus slots required

Antenna style

Limits range and performance

Versatile antenna systems helps

Compaq iPaq

PCMCIA Slot

Limited Battery Life


13/28


Which Technology Do You Use?b, a or g?

Decision should be based on requirements ofsystem/users

User bandwidth requirements

Mb/user

User density

Number of users per APOverall implementation cost

Total cost/cost per user

Physical security requirements

Hidden, locked down

Upgrade requirements

Upgrade to .11a or .11g , ADD .11a, security requirements

Client availability

What type of clients, what vendors radios, who decides

Client platform features

Barcode scanners, PDAs, card bus PCI or PCMCIA


14/28


Dual Mode Products

Dual band access points are available now

Provide access and coverage for both2.4 and 5GHz clients

Can be used to increase aggregate bandwidthper cell

5GHz Radioand Antenna

2.4GHzAntennas

Access PointMain Processor

2.4GHzRF

System

5GHzRF

System


15/28


Migrating the Cisco Aironet 1200Series from 802.11b to Dual Mode

802.11b

+ 802.11a =802.11b+a

(802.11g+a)

2.4GHzAntenna

Connectors

5GHz Antenna

(Attached to

Radio)

5GHz

Radio

5GHz Antenna IsAdjustable for

Mounting and for

Antenna Selection

5GHz Antenna in 6dBiDiversity Patch Mode

5GHz Antenna in

2dBi DiversityDipole Mode


16/28


Cisco Aironet 1200:Technology Design Innovation

802.11a/UNII-1 module and antenna must be integral (FCC)

Multiple mounting options for maximum flexibility

Dual-function, high-performance diversity antenna

Metal case for installation in harsh environments

Wall MountedCeiling Mounted


17/28


Dual Mode Coverage

5GHz differentcoverage areas

Mixing technologies

will require a goodup-front design

Provides migration pathand increased throughput

Design the 2.4GHz cellsize to complement future5GHz deployment

11Mb @ 2.4GHz 24Mb @ 5GHz

54Mb @ 5GHz


18/28


Channels Selection

Proper implementationrequires channel definition

Adjacent cells should

avoid overlapping(2.4GHz) or adjacent(5GHz) channels

8 channels in 802.11a iseasier to deploy

More channels providegreater aggregatebandwidth

802.11a WLAN Channels

802.11b/g WLAN Channels

1 2 3 4 5 6 7 8 9 10 112400 2483


19/28


Dual Band Deployment

11 1

1 1

6

66

6 6

6

1111

1111

11

11

6 611

38

85

3

1

51

57 1

3

1

3

8

3

1

8

3 & 11

8 & 1

8 & 1

5&6

3 & 11

1 & 6

5 & 1

1 & 6

5 & 11

7 & 6 1 & 6

3 & 11

1 & 6

3 & 11

8 & 1

3 & 11

1 & 1

8 & 6

802.11a802.11b

802.11b

802.11a


20/28


Healthcare Facility

Survey was basedon 11Mb

Antennas arediversity ceilingmount omni(blends in well)except courtyard

Works well exceptradiology!

Courtyard

Radiology

AntennaLocations

Channel 1Channel 6

Channel 11

6dBiPatch

Antenna

All Antennas Are Ceiling Mount

Diversity, Omni Antennas ExceptCourtyard Antenna


21/28


Courtyard

Radiology

AntennaLocations

Channel 1Channel 6

Channel 11

6dBiPatch

Antenna

Healthcare Facility

Add dual bandAPs for radiology

802.11b 2.4Ghzdevices usableeverywhere

802.11a provideshigher data ratesfor radiology room

All Antennas Are Ceiling Mount

Diversity, Omni Antennas ExceptCourtyard Antenna5GHz Cell


22/28


Manufacturing

Aircraft manufacturing floor(802.11b)

Normal network connectivitymed BW bar codinglimited BW printing invoices limited BW (802.11b)

Video images for inspection, troubleshootinghigh bandwidth (802.11a)

IP phonelimited use, med bandwidth (802.11b)

6 Dual Band APs,Provide 802.11bCoverage

6 Dual Band APs,Plus 6 Other 5GHzOnly APs Provide802.11a Coverage


23/28


Enterprise Office Area

Dual band APs installed

802.11b cell size reducedby reducing TX power to

5mW and dipole antennas

802.11a cell size same as802.11b

802.11b used for normalnetwork connection

802.11a used for videosystems


24/28


CiscoWorks Wireless LAN SolutionEngine Overview

CiscoWorks Wireless LAN

Solution Engine

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

Specialized application formanaging the Cisco WLANequipment, includingAP1200

Centralized configurationof large deployments ofCisco Access Points

Security policy andfault/performance

monitoring of the CiscoWLAN infrastructure

Turnkey, appliance-basedmanagement solution


25/28


Expected Upgrade Paths

802.11e

Firmware or software upgrade

802.11g

Hardware upgrade; radios need to be replaced

AP upgrade will require a card bus or PCI bus to meet 54Mbdata requirements

802.11h

Software/firmware upgrade likely for most products

802.11iSoftware upgrades for some features

AES will likely require a hardware upgrade, or will result in asmuch as 5075 % reduction in throughput performance


26/28


Summary

Higher data rates are available todaywith 802.11a

Careful design permits installation today with

either plans to upgrade, or to install dual bandsystems

Careful design can permit higher aggregatebandwidth today (65Mb per AP) with room to

grow to 108Mb when .11g is available Design must include limitation of new

technologies


27/28



28/28


www.cisco.com/discuss/networking

Visit the NetworkingProfessionals Connection

Discussion forums

Online events

Biweekly newsletter

designing wireless

Documents