Session 3B: PANEL 1
Building and Managing Large Wireless
LANs - Real World Experiences
Moderator
Victor Bahl, Microsoft Research
Monday, September 29 1997
10:30 a.m. - 12:00 p.m.
Building and Managing Large Wireless
LANs - Real World Experiences
Moderator
Victor Bahl, Microsoft Research Redmond U.S.A
Panelist (in order of presentations)
Barry Forde, Lancaster University, U. K.
David Hughes, Old Colorado Communications, U.S.A.
Ben Bennington, Carnegie Mellon University, U.S.A.
Nigel Davies, University of Lancaster, U. K.
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Microsoft Research
Victor Bahl
Wireless LANs
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Provide Un-tethered access to the NET (wired LANs)

Support (limited and sporadic) host mobility (1.4 m/sec)
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Support connection-oriented and connection-less services

Support heterogeneous traffic classes (it’s the 90’s !)
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Are cost effective, secure and provide QoS (really?)
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Minimum data rate: 1-2 Mbps; Minimum coverage: 100m
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Transmission technology - RF, IR

Are standards compliant - IEEE 802.11, HIPERLAN 1, HIPERLAN 2 /
WATM(?)

Can work with infrastructure support and without infrastructure
support (ad-hoc networks)
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Microsoft Research
Victor Bahl
Application Areas

Internet access via enterprise networks, home networks, and public
networks
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LAN extension at hospitals, factory floors, older buildings, rural areas

Inter-LAN bridges - point-to-point connectivity between buidings

On-the-fly networks - conference registrations, campaign
headquarters, military camps, airplanes, trains

Nomadic access to printers, to light switches!

Education - wireless class rooms, wireless internet access

Wearable (BodyLAN) - Field service operators
9/27/97
Microsoft Research
Victor Bahl
MobiCom ‘97 Spontaneous Survey

How many of you have heard of a Wireless LAN?

How many of you regularly use a wireless LAN for real
work? (student researchers don’t count)

How many of you would like to use a Wireless LAN?
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Microsoft Research
Victor Bahl
Wireless LANs - A Brief History?

Wireless data modems first appeared in 1981-82 (15 years ago !)

FCC allocated the ISM (2.4 GHz) band for commercial (WLAN)
applications in 1985 (12 years ago !)


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First “high speed” 2 Mbps wireless LAN products appeared in late
1990 (7 years ago !)
Work on IEEE 802.11 (CSMA/CA) began in 1990 (first draft in 1994)
ETSI’s HIPERLAN group set up in mid 1991 (6 years ago) (spectrum
allocated by CEPT at 5.15-5.25 GHz in early 1993)
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Microsoft Research
Victor Bahl
Why are wireless LANs not Ubiquitous ?

Lack of horizontal market focus, limited successes in vertical markets
Infrastructure build-up has been slow

Battery life is a huge problem

Applications behave poorly with dropped packets, and wireless packets
do get dropped

Disappointing ease-of-use (configuration requires a graduate degree),
inadequate displays, keyboards, and user-interfaces for mobile handhelds

The case for value .v.s. cost is unclear
Wireless PCMCIA adapters - $600-$800, Access points $1500-2500
Wired Ethernet PCMCIA adapters - $150 - $500, Hubs 12-port $150
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Microsoft Research
Victor Bahl
Questions for the Panelist ?

Tell us about your WLAN deployment

What have your learnt in the process? - give us guidelines for building
our own large scale wireless LANs

Tell us about potential pitfalls - we are interesting in hearing horror
stories?

Do you believe the technology is ready for prime time? If not then
consider what we do:
We are researchers…
Share with us your wish list -- what would you like us to focus on?
We are practitioners...
Tell us what we should fix and what more should we build?
Challenge for the panelist - Make us believe !
9/27/97
Microsoft Research
Victor Bahl
Panel Introductions
Barry Forde (b.forde@lancaster.ac.uk)


Assistant Director of Computing at the University of Lancaster
Pioneered the development of a low-cost high speed microwave
inter-institute radio network - EDNET
http://www.ednet.lancs.ac.uk/
David R. Hughes (dave@oldcolo.com)


Partner of The Old Colorado City Communications
Wireless LAN evangelist. Builds Wireless LANs in rural and hard
to wire areas under the auspicious of NSF
http://wireless.oldcolo.com/
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Microsoft Research
Victor Bahl
Panel Introductions
(Continued)
Bernard J. Bennington (benb@andre.cmu.edu)
 Director of the Information Networking Institute at CMU, U.S.A.
 Principal visionary and architect behind the largest (campuswide) WLAN deployment (> 110 base stations) in the US
http://www.ini.cmu.edu/WIRELESS/
Nigel Davies (nigel@comp.lancs.ac.uk)
 Professor at Lancaster University, U.K.
 In the process of deploying WaveLAN based WLAN with about
75% coverage and creating context-sensitive mobile multimedia
applications for city visitors
http://www.comp.lanc.ac.uk/computing/research/mpg/
9/27/97
Microsoft Research
Victor Bahl
Final thoughts…
Some final thoughts on WLANS


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The killer application is “access everywhere”. To succeed this
is the one that has to be promoted energetically (need to go
after the horizontal markets)
WLAN have to be very easy to configure, maintain, and
manage.
WLAN have to be secure and private – key to enterprise
networking

Researchers should continue working on improvements in
speed, reliability, latency, and coverage

Practitioners should continue working on system design and
packaging, form factors, infrastructure, applications and ease of
use
9/27/97
Microsoft Research
Victor Bahl
Putting WLANs in perspective

It has taken wired LANs over 30 years to get to
where we are today

Wireless LANs (products) have only been
around for 7 years….
Thanks !
9/27/97
Microsoft Research
Victor Bahl
ACM SIGMOBILE
http://www.acm.org/sigmobile
Become a member today !
2
 Enjoy 4 issues of ACM MC R (SIGMOBILE’s official publication)
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IETF’s Mobile IP, MANET and Wireless ATM, conference
reports, book reviews, paper reviews, vision statements, events
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outside.
9/27/97
Microsoft Research
Victor Bahl