Chuck Bartel May 11, 2000 Wireless & Mobile Computing- Deployment Issues & Challenges.

May 11, 2000 Chuck Bartel

Wireless & Mobile Computing-Deployment Issues & Challenges

Wireless Andrew

Project OverviewChuck Bartel


Carnegie Mellon Background

Private research university (R1)

50+ buildings on 100+ acre campus

Half of buildings are on contiguous main campus


Background -- 1994

Dozens of Mobile, Wearable, and Wireless Computing ProjectsMultidisciplinary Collaboration Spanning Several Campus BuildingsMore than $20M in Research FundingNo Comprehensive Network-- Each Research Project Left to Fend for Itself


Vision -- 1994

Establish Common Research NetworkNSF Grant - $550,000 over 2 yearsBuild an Experimental, High-Speed, Wireless Network Support research projects in wireless

communication and mobile computing.


Implementation -- 1995-1998

No Standard Existed for Wireless LANs Evaluation + Selection: ATT/Lucent 915Mhz

Deployed network in 5 campus buildingsEnable use by approximately 150 usersResearch Network = Limited Support


Background -- 1998

Successful Wireless Research Network Growing use of LaptopsNeed for Wireless Production NetworkWireless LAN Standard 802.11 Adopted by IEEE Lucent Grant to Support Campus-Wide Deployment (400 Access Points/cards)


Implementation -- 1998-2000

Deploy Network Campuswide 30+ Buildings (2.8M sq ft) + Outdoor

Areas

Use by Virtually Anyone on CampusProvide Support Equivalent to Wired NetworkLucent’s WaveLAN Product -2.4GHz, IEEE 802.11 Compliant

Deployment Issues & Challenges


Access Point Access Point - network - network device that links device that links wireless stations to the wireless stations to the wired network -- wired network -- $900/unit$900/unit

Wireless NIC cardsWireless NIC cards- EISA - EISA bus or PC card -radio bus or PC card -radio transceivers for the end transceivers for the end users -- users -- $795/card$795/card

$595/card$595/card $275/card$275/card $125/card$125/card

Key Components- Wireless LAN


For every Access Point in a building, we need: For every Access Point in a building, we need: •110 vac plug 110 vac plug •Data cable capable of supporting a 10BaseT Data cable capable of supporting a 10BaseT connectionconnection

Since most of the Access Points end up above Since most of the Access Points end up above ceilings or other out of the way places, new ceilings or other out of the way places, new dedicated cables needed to be installed.dedicated cables needed to be installed.

Avg. cost per installed Avg. cost per installed AP $1.9K (Cost of AP- $.9K)AP $1.9K (Cost of AP- $.9K)

Wireless doesn’t necessarily mean Without WiresWireless doesn’t necessarily mean Without Wires


Design factors to consider

Interference

Mobility – Roaming

Coverage vs Capacity


Examples of potential interference sources in the

2.4GHz ISM band (IEEE 802.11) Microwave ovens 2.4GHz Cordless phones Bluetooth Other 802.11 LAN devices Other 2.4GHz LAN devicesHow do you regulate these on your campus?

Can you? Should you?

InterferenceInterference


Other complicating factors

Mobility complicates wireless designs. Wireless design is as much Art as

Science. The wireless industry is evolving their

products to support campus environments (but they are still behind the wired side of networking).


Keys to Design Success (for CMU)

We developed new approaches to building-wide wireless design with the vendor.Colorized coverage mapsDesign review meetingsDesigned for coverage (not for capacity)

Based on our experiences, the vendor improved their design tools.



Design Futures

The “Walkabout” WLAN Design Tool

Alex HillsCarnegie Mellon University


CMU’s Manual Design ProcessEnhances WLAN Performance

Complete coverage no gaps

Minimize co-channel overlap capacity

Lucent design manual based on process developed at CMU


What Is Needed To Improve Design Process

A design process that is: Fast Easy to use Correct!

The “Walkabout” tool: Is much faster than manual process Requires minimal training Requires no building drawings Uses inexpensive hardware


Walkabout Hardware Requirement

Notebook computer

Harness

Position locator


Walkabout Development Phases

Phase I Creates coverage map Assigns frequencies to APs

Phase II Predicts coverage map (“what if”)

after APs moved to new locations

Phase III Recommends “first cut” design


Walkabout Phase I Tool

Temporarily position APsWalk around target space single floor building multi-floor building outdoor space

Results: Coverage map Frequency assignment


Multi AP Display


For more info contact:

Alex HillsCarnegie Mellon University

(412) [email protected]


Wireless Andrew Infrastructure

Standards-Based Wireless LAN in all Academic and Administrative BuildingsComprehensive Coverage with Roaming Enabled (Mobility is Seamless)Wireless LAN is Connected to the Campus Backbone and InternetSupporting 600-1000 UsersAdd’l Info available at URL:

http://www.cmu.edu/computing/wireless



Where are we now?

We cover 14+ buildings (to date)- 240 APsWe cover 14+ buildings (to date)- 240 APs We cover over 2 M sq. ft. of office/lab/classroom We cover over 2 M sq. ft. of office/lab/classroom

spacespace We cover roughly 60% of the academic campus.We cover roughly 60% of the academic campus. We have 800+ usersWe have 800+ users

We will be adding another 16 bldgs. ( 800K sq. ft.) by We will be adding another 16 bldgs. ( 800K sq. ft.) by 6/30/2000. –Approx. 84 APs6/30/2000. –Approx. 84 APs


Academic andAdministrative

Buildings

Residence Halls, Parking, etc

Wireless Campus by June


How Much?? $$$, coverage

Average cost of wireless: <$1K for AP, <$1K for power/data install, + wired network infrastructure costs+design labor costs.Avg pwr/data install schedule– 8 locations / wkAvg AP installs - 8 per dayAP to sq.ft. density: depends on building construction and arch concerns, ex: older construction 25 A.P.s cover 228Ksq.ft., newer construction 12 A.P.s cover 210Ksq.ft.Best coverage 17.5Ksqft/AP, Worst 3.4Ksqft/APYour mileage WILL VARY!!!


Q & A


Wireless Andrew Issues/Futures Coverage vs capacity – Why not both? “Airspace policy” and interference –

Bluetooth,… Keeping up with demand- scaling issues Security-Authentication Next Gen 802.11(a) –5Ghz Issues: Fork-lift upgrade? Ease of transition?John Schafer will cover some of these topics


Uses of wireless infrastructure

Untethered access to campus network: Follow-on project - Handheld Andrew: enhancing usability of palm and HPCs with access to campus network – Researcher’s “Field of Dreams”

Tracy Futhey will cover some of these topics


Wireless “Bake-off”1 1.208666374 1.279168497 1.352422779 1.358424828 1.35842482811 1.252563788 1.339435092 1.400756011 1.4115361731 1.352746176 1.4367513 1.5192119341 1.292107434 1.3673037621 1.31168499111 1.193162701 1.2752944 1.346130738 1.3519286231 1.652914473 2.127679866 2.631609064 4.1667238881 1.143277757 1.2464651311 1.178031198 1.2540179631 1.851851852 2.5925925931 1.6747663551 1.453639515 1.936200173 2.2598570191 1.688360862 1.976205925 2.762338505111 1.688367727 2.147367381 2.845476704

29 20 15 10 5 11 1.262023804 1.675139265 2.725030441 3.724414134 6.1714975851 1.381327617 1.604411831 1.942093224 1.930880759 1.358424828

1 5 10 15 20 296.171497585 3.724414134 2.725030441 1.675139265 1.262023804 11.358424828 1.930880759 1.942093224 1.604411831 1.381327617 1

1 5 10 15 20 2946,397 46,397 46,192 43,690 41,282 34,15545,990 29,873 18,558 12,336 10,034 7,452

Effect of network loading on a single host

41,282

34,155

18,558

7,452

43,690

46,19246,39746,397

10,034

29,873

45,990

12,336

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000

45,000

50,000

1 5 10 15 20 29

Number of simultaneous FTP transfers

FTP

tran

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Bytes p

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10-base-T wired

Wireless

46,397

45,990

46,39729,873

46,192

18,558

43,690

12,336

41,282

10,034

34,155

7,452

0 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 45,000 50,000

FTP transfer rate in Bytes per Second

1

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Effect of network loading on a single host

Wireless

10-base-T wired

Penn State Wireless Experiences

Russell Vaught

Chuck Bartel May 11, 2000 Wireless & Mobile Computing- Deployment Issues & Challenges.

Documents

interference slide

wireless communication

wireless stations

wireless designs

wireless doesnt

wireless industry

compliant slide

limited support slide