wireless lans a new computing experience doug jackson director, technology customer services...
TRANSCRIPT
Wireless LANs A New Computing Experience
Doug Jackson
Director, Technology Customer Services
University of Texas at Dallas
EDUTEX 2002: Austin
Copyright Doug Jackson 2002. This work is the intellectual property of the author. Permission is granted for this material to be shared for non-commercial, educational purposes, provided that this copyright statement appears on the reproduced materials and notice is given that the copying is by permission of the author. To disseminate otherwise or to republish requires written permission from the author.
Introduction
WLAN Basics WLAN Standards, Pending Issues Deployment at UTD
UTD WLAN History AirUTD UTD Plans
Tips’N’Tricks URLs
Baylor’s AirBear …
The Basics of WLANs
Ubiquitous, Anytime, Anywhere network connectivity!
The Basics of WLANs
PAN LAN WAN
Access speed 1-2mb 11mb >56kb
Range 10m 100-400m
global
Standard IEEE802.11b
GPRS1xRTT
Scalability Lowdevicespecific
Mediumethernet
Highregional
Infrastructure
Architecture FHSS DSSS cellular
The Basics of WLANs
Wireless LAN is almost exclusively Spread Spectrum Radio
3 Basic WLAN Topologies- Infrared (IRDA) Frequency Hopping (FHSS) Direct Sequence (DSSS)
FH greater density, shorter range, slower speed, less prone to interference (79 channels)
DS lower density, greater range, higher speed, more susceptible to interference (15 channels)
WLAN Standards
Standards (key to interoperability) IEEE 802.11 802.11b- DSSS @11Mbps 2.4GHz 802.11a- DSSS @54Mbps 5GHz
802.11g- DSSS @22Mbps 2.4GHz 802.11e- DSSS @22Mbps w/QoS
802.11 is “shared ethernet”
WLAN Pending Issues
802.11a products beginning to show up
802.11g products may appear soon
Transitioning to 802.11a or stay
with 802.11b (or .11g)?
WLAN Pending Issues
Why 802.11a? Greater bandwidth (54Mb) Less potential interference (5GHz) More non-overlapping channels
Why 802.11b? Widely available Greater range, lower power needs
Why 802.11g? Faster than 802.11b (24Mb vs 11Mb)
UTD WLAN History
1999-2000: Symbol (FHSS) Largest Classroom building Conference Center Ad Hoc networking “kits”
2000-2001: Orinoco 802.11b Student apartment complex Student Union Cafeteria & Pub Selected Common Areas Auditoriums & Largest classrooms
AirUTD
Associates an “identity” with the wireless deployment.
People know what you are talking about without a lot of explanations
People know what/where to look for more information about wireless networking on campus
UTD Plans
Deployment Locations
More common areas, especially outdoors and lounges
Servicing specific departmental requests
Begin replacement of Symbol AP locations
UTD Plans
Deployment Issues
Re-purpose Symbol AP’s for secure admin services
Deploy 802.11b with 802.11a in mind (25db SNR for all service areas)
Delay migration to 802.11a until dual function (11b & 11a) cards become available
WLAN Deployment Issues
Site Survey Performed with 802.11a in mind Minimum coverage of 25 dB SNR @ 2.4 GHz
25 dB @ 2.4 GHz extrapolates to ~18 dB @ 5 GHz
18 dB @ 802.11a ensures 24 Mbps
Bandwidth vs. SNR @ 2.4 GHz 11 Mbps: 16 dB 5.5 Mbps: 11 dB 2 Mbps: 7 dB 1 Mbps: 4 dB
Bandwidth vs. SNR @ 5 GHz 54 Mbps: 28 dB 24 Mbps: 19 dB 12 Mbps: 14 dB 6 Mbps: 11 dB
WLAN Deployment Issues
Deployment Strategy (Existing Structures)
“Throw N Go” Pre-Deployment Subsequent Site Survey testing Formal Site Design Adjust Physical Deployments to
Match Design
WLAN Deployment Issues
Deployment Strategy
(New Structures)
Design network POPs for pending WLAN deployment
Hold WLAN deployment until construction complete
Follow “Existing Structure” plan
Tips N Tricks #1
In deploying 802.11b & Planning for 802.11a, consider- 25db SNR should work with 11a
Don’t forget the 6’ columns of water when testing
Consider antennas w/ 15’ cables for “hard to reach” spots
Use Power-over-Ethernet whenever possible
Tips N Tricks #2
Airspace ownership? Banned devices?
Roaming: Is it an Issue? Security
Authentication vs Authorization (user versus machine)
Encryption and/or VPN WLAN Appliances? Software
Tools?
Tips N Tricks #3
Other Issues- Number of Users Colocated AP’s- 11b allows 3
(11a - 8) Monitoring for Failures
Notable Vendor Products SitePlanner & SiteSpy NetMotion
URLs
WECA http://www.wirelessethernet.org/
Security http://www.dell.com/us/en/hied/topics/vectors_2001-wireless_security.htm
High Bandwidth Wireless LANs http://www.nysernet.org/tec0.html
U Tenn Deployment http://www.ncne.nlanr.net/training/techs/2001/0514/presen
tations/pptfiles/200105-latimer1.ppt
URLs
For copies of this presentation: Email: [email protected]
For more information:(White papers & more URL’s)
http://www.utdallas.edu/ir/wlans/
The END
Click here for
Baylor’s AirBear