Download A Data Warehousing Approach for Mobile Data Management

Wireless and Mobile
Computing and Networking at
the University of Florida
Technology, Infrastructure & Research
University of Florida
http://net-services.ufl.edu/wireless
http://www.harris.cise.ufl.edu
Talk Overview
• Technology
– Mobile Devices
– Wireless Networks
– The 802.11b Wireless LAN
• Infrastructure
– The Wireless campus project
• Synergistic Research Activities
– Helal (CISE): Wireless & Mobile Tech for the Elders
– Others ..
(Mobile Information Appliances)
Subscriber Identification
Module (SIM)
Platform Limitations
•
•
•
•
•
•
Limited battery power
Limited memory capacity
Limited processing power (in some devices)
Limited I/O modalities (no keyboard)
Limited display size, resolution & refresh rate
Wide variety of devices lacking platform
standardization (started to change with advent
of Java 2 Micro-Edition)
Wireless Networks
Global
Satellite
Suburban
Urban
In-Building
Micro-Cell
Macro-Cell
Pico-Cell
dik ©
In-Room
(BlueTooth)
Wireless Networks
UMTS
Wireless Data Networks
• Unlicensed Frequency
– The 802.11 Wireless LAN
– Bluetooth
– Infrared
• Licensed Frequency
– 2G-2.5G: D-AMPS, CDMA, GSM, iDEN, CDPD
– 3G: CDMA2000, W-CDMA
• Mobile Networking
– CDPD: Wireless packet data
– iDEN: Wireless packet data & Mobile IP
– GPRS & EDGE: Wireless packet data & other mobile
networking protocols (competition to Mobile IP)
802.11
• Unlicensed Frequency
– indoor/outdoor coverage with cell sizes ranging
from 300 feet (indoor) to 1000 feet (outdoor)
– Bandwidth:
•
•
•
•
802.11b: 11Mb/s
802.11a: 100Mb/s
802.11g: 54Mb/s;
Effective bandwidth in presence of multiple users is less
(for instance: 6Mb/s in 803.11b)
Network Limitations
• Low bandwidth
– Limited spectrum, interference
• High latency (in 2G and 3G)
• High Bit Error Rate (BER)
– bad carrier signal, handoffs
• Frequent disconnection
• Heterogeneity of network coverage
• In many cases, lack of network infrastructure  Ad-hoc
Networks
• Preserving Return on Investment in presence of a rapidly
evolving technology
Challenges
Mobile environment differs greatly from the
traditional fixed-network environment. The
difference is limitations that can be divided into
two categories.
Platform diversity and limitations – which
platform to use for a certain application?
Network limitations -- which network to
support? What if the devices use different
network interfaces?
Which Platform?
Mobile User
Target Platforms
Platform
Mobile
Information
Device (MID)
Palm-sized
Devices
Jupiter
class (HPC)
Laptops
Tablet PC
Desktop
Examples
Cell phone
PDA
Tablets
Notebook
Fujitsu,
ViewSonic, ..
Workstation
Screen Size
Extremely small
Small
Small to
medium
Medium to
large
Medium to
large
Large
Location/
Use
Extremely small
and mobile
Small and
extremely
mobile
Fairly small
and mobile
Fairly
powerful
devices,
mobile
Fairly
powerful
devices,
mobile
Large
devices, fixed
location
Input
devices /
navigation
Specialized
keys.
Limited,
small keypad
and/or penbased.
Usually penbased, small
keyboard
Full-size
keyboard,
mouse,
voice
Stylus,
wireless KB
and Voice
Keyboard,
mouse, voice,
etc.
Operating Systems
OS
KVM
Palm
OS
Symbian Windows CE /
EPOC
Pocket PC
Windows
98/NT/2000,
Unix, Mac
OS
Memory
footprint
Very
Small
small
Small to
Medium
Small to medium
Large
Memory
requireme
nts
A few
100KB
1MB –
4MB
4 MB – 32
MB
16 MB – 32MB
> 32 MB
Developm
ent/debug
ging tools
Some
Some
Some
Some
Numerous
Implementation Language
Language
C/C++
Java
C#
Code
Native, platform specific
Universal, platform
independent
Platform specific
Development
difficulty/speed
Fair/medium
Moderate/fast
fair/fast
Porting to other
platforms
Difficult
Very little or no porting
Difficult
Development/Debu
gging tools
Excellent
Excellent
Excellent
Speed
Excellent/platform
optimized
Poor to good, usually not
platform optimized
Excellent/platform
optimized
Wireless Infrastructure at UF
Recognizing the importance and impact of using
wireless and mobile technology in education and
research, the University Network Services and
Several University Colleges and Schools have
committed to provide for the indoor and outdoor
deployment of the 802.11b wireless LAN
technology.
Short History of Wireless at UF
• Lombardi’s initiative -- First Wireless Classroom
Trial: in CSE Building, Spring 1999
– 20 IBM thinkpads, 20 PC cards, two Bay Network access
points (2Mbps), Static IP configurations – no authentication
• The University IE Proposal to the National Science
Foundation (even though was not funded, it brought
together awareness and commitment of various
University entities)
• Outdoor campus deployment begun (Jan 2001)
• CISE deployment (May 2001)
• Law School deployment (July 2001)
• College of Engineering all-classroom deployment
(May 2001 – Nov 2001)
Blueprints of the Big Picture
We envision that many educational activities can be taken to a
higher level of effectiveness if this opportune technology is
exploited properly. In particular, we identify several undergraduate
curricula that, for a long time, have been deprived from having the
appropriate computing environments that they needed. Botany,
geology, animal science, agriculture, anthropology, remote sensing,
architecture, veterinary medicine, civil engineering, exercise
physiology, and forestry are among the many curricula that would
benefit significantly from the wireless outdoor laboratory, a concept
that can be achieved with today’s technology. By bringing the
(wireless) network and the (portable) computers much closer to the
actual subjects of study (plants, humans, trees, crops, animals, roads,
building, etc.), it will be possible to design and develop substantially
effective curricula for undergraduate and graduate education.
Goals of the Wireless Campus
Project
• Create a Pervasive Computing environment within the
University of Florida campus, by exploiting wireless,
mobile networking technology and portable computing
appliances.
• Modify and extend existing curricula in several major
areas to take advantage of the wireless connectivity that
will blanket UF campus.
• Explore research issues in Pervasive Computing (e.g.
projects undertaken in the Harris Lab by Dr. Helal)
• Potentially, integrate some University services into the
wireless network.
Objectives of the Wireless
Campus Project
– Indoor and outdoor wireless connectivity
– Ideally: Single IP, secure roaming solution – pending
industry adoption of IPv6
– Support for a variety of devices (notebooks, iPAQs,
Palms, wearable computers, …)
– Different views of network resources for different student
groups
– Anticipated use of thin client technology
– Innovative solutions for software license management
(not all mobile users active at once – licenses will need to
be spread over multiple network domains (unusual)
– Challenging requirements: security & scalability
Sample Research Activities on
Mobile and Wireless
International Center on Pervasive
Technology for Successful Aging
Dr. Bill Mann, Director
Dr. Sumi Helal, Director of Technology Development
Rehabilitation Engineering Research Center on
Technology for Successful Aging
University of Florida
Funded by
National Institute on Disability and
Rehabilitation Research
Pervasive Technology for Elders
• Health care system ($$ & Nurses) will not sustain
the increasing number of elders
• Goal: how to help elders stay at home and live
independently
• Broad center activities:
– Create smart spaces
– Create magic Wands for interaction with smart spaces
– Create and perform extensive testing of applications
that use the smart home/phone infrastructure
Automatically refill
prescription
Check if
laundry is done
Sense and see
visitors/strangers
at front door
Turn on/off
lights (and
visually
inspect)
other
rooms.
Check locks
on doors and
windows
Monitor
of kitchen:
oven and
stove on/off;
temp.
Call in for
help and
Assistance
Order groceries
with dietary
restrictions
Other
Services
Call in
a nurse
X10 Powerline
Home Network
High-speed Home
LAN Network
TINI
Tini Internet
Interface
(Micro-controller)
Wireless
Access
Point
TINI
Wireless
Local
Connectivity
Internet
Wireless Cellular
Packet Network
(services)
X10
Module
X10
Module
Wireless packet
data (cellular)
Static IP
X10
Module
RF1
App
Clients
Proxy
Software
for X10,
TINI, &
Internet
Services
Static IP
X10
Module
Networked
Home Server
RF2
TINI
Wireless
Access
Point
Home Broadband
Service Provider
Appliance or
home device
Dual Interface
Smart Phone
TINI
TINI
Wireless Local
connectivity
(802.11x, or
Bluetooth)
X10
Module
X10
Controller
X10
Module
X10
Module
X10
Module
Wireless
Access
Point
Wireless, ad-hoc appliances, devices, or
information sources: (e.g.: TV remote
control, door knob, Smart Tags, Garage
door opener, Java rings, etc.)
Sample Applications
Location Tracker: elder finds her whereabouts
Security Alert: alerting the elder to security breaches
Unlocking Device: lock/unlock doors and windows
Intercom: elder talks to person at the door
Emergency Alert: phone alerts care giver
Reverse Locator: others find elder’s whereabouts
Mapmaker: elder finds directions to destinations
Pager for TV Remote: phone pages TV remote
Switch functions: turn on/off light, stereo, etc.
Sample Applications
Alert/Alarm: phone alarms elder to take medications
Weather Info: elder queries phone for weather conditions
Mail Notification: phone notifies elder of mail arrival
Grocery shopping assistant: phone as shopping assistant
Dictation: phone takes and organize notes from elder
On demand service ordering: elder shops (eg. order a pizza)
Remote monitoring: phone shows images of remote places
Bookkeeping of health measurements: taking blood pressure
Video Tele-conferencing
Main Entrance to ICTA
ICTA
Planned
Meeting
Table
Front
door
Elder
Home
Mockup
Servers
Room 447,
CSE Bldg.
Workstations
Renovation
Storage
Pins
Window
Workshop Area
Early Prototyping
Pharmacy
Client
Request
Query
Reply
Query
Response
UnLatch
Response
HTTP Interface
Proxy
Server
Scanner
Medicine Bottle
Unlock request
Data written to port
TINI Board
Generated Pulse
Circuit
Video
802.11 Wireless Networking
History
• In 1985, as an attempt to stimulate the production and use
of wireless network products, the FCC modified Part 15 of
the radio spectrum regulation, which governs unlicensed
devices. The modification authorized wireless network
products to operate in the Industrial, Scientific, and
Medical (ISM) bands using spread spectrum modulation.
FCC ISM Restrictions
• Frequency restrictions
– 902-928 MHz
– 2.4-2.4835 GHz
– 5.725-5.850 GHz
• 1 Watt power restriction
– 100mW for WLANs
• Spread Spectrum transmission
History
• The first wireless LAN technologies
operated in the 900MHz band and were low
speed (1-2Mbps), proprietary offerings.
• 1992, wireless LAN makers began
developing products operating in the
unlicensed 2.4 GHz frequency band.
• IEEE approved 802.11 standard in 1997
802.11 transmission methods
• FHSS
• DSSS
• IR
Frequency Hopping Spread
Spectrum (FHSS)
• minimum 75 non-overlapping channels with a maximum 1
MHz bandwidth
• Three possible hop patterns (22 hops in a given pattern)
• Minimum rate of 2.5 hops/s
• Maximum dwell time of 400ms
Direct Sequence Spread
Spectrum (DSSS)
• Combines a data signal with a higher data rate bit sequence
(chipping code). Minimum of 10.
• 14 twenty-two MHz channels
Characteristics of FHSS
•
•
•
•
•
•
Lower cost
Lowest power consumption
More tolerant to signal interference
Lower potential data rates
Less range than direct sequence
Less interoperability
Characteristics of DHSS
•
•
•
•
•
•
Highest cost
Highest power consumption
Less tolerant to interference
Highest potential data rates
Better range than frequency hopping
Better interoperability
802.11 Layers
802.11 Data Link Layer
Mechanisms
•
•
•
•
•
CSMA/CA
RTS/CTS
CRC checksum
Acknowledgments
Fragmentation
802.11 Features
•
•
•
•
•
Beacon frames
Authentication
Roaming
Security
Power saving
Security Features
• Service Set Identifier (SSID)
(also called Network Identifier or
Network Name)
• MAC address filtering
• Wired Equivalent Privacy (WEP)
encryption
WEP Encryption
• Algorithm based on RSA RC4 algorithm
• 40bit and 128bit keys
• Security partially relies on maintaining the
secrecy of the WEP key.
• Shown to be weak
Wireless Access Modes
• Ad hoc
• Infrastructure
802.11 Future
• 802.11g
– 2.4Ghz frequency band, >20Mbps data rate
• 802.11a
– 5.7Ghz supporting data rates up to 54Mbs.
UF Wireless Deployment
UF Wireless Deployment
•
•
•
•
•
Cisco Aironet 350 series access points
Authenticated via Gatorlink userid
Not using WEP encryption
No registered MAC address
Area VLANs and a common
configuration to allow roaming
Compatibility
• Wireless Ethernet Compatibility Alliance
(WECA)
Wireless Fidelity - WiFi
Channel Coordination
• 802.11b DSSS hardware only offers 11 channels.
• At most, only three non-overlapping channels can
be used (1,6, and 11).
• Where common channels overlap there will be cochannel interference which will negatively impact
performance.
DSSS Channels
Channel Coordination
Vertical Channel Coordination
Basic Topology
UF Core
Authentication
Gateway
Core POP
Access Point
VPN Authentication
UF Core
Authentication
Gateway
CORE POP
VPN
Concentrator
Access Point
VPN connection
VLAN Trunking
• VLAN trunking (802.1q) allows the transport of
multiple 'logical' (Virtual) ethernets over one
single physical ethernet.
• This allows the delivery of authentication VLANs
in parallel with building VLAN(s).
• This use of VLANs allows roaming through
wireless areas that share the same VLAN.
VLAN Trunking Design
CORE POP
Authentication VLAN
passes through CORE POP
at layer 2 only and is not
routed. Routing for the
VLAN is performed by the
Authentication Gateway.
Routed connection for
Authentication Network
Authentication
Gateway
Authentication
VLAN
802.11q
Trunk
Authentication
VLAN
Access Point
Building
VLAN(s)
Access Point
Authentication
VLAN
BPOP Switch
Building Network(s)
Area VLAN Implementation
CORE POP
Authentication
Gateway
UF Core
Authentication
VLAN
802.11q Trunk
Authentication
VLAN
Authentication
VLAN
Building Network(s)
Building Network(s)
Access Point
Access Point
Problems/Issues
•
•
•
•
•
•
•
•
Departmental wireless networks
Rogue wireless networks
Interference from other devices
Security
Malicious interference
Interoperability
Competing technology
Emerging technology
Isolated Deployment
If you are deploying wireless service and it
can not be incorporated into the campus
plan the following steps are critical:
– Contact Network Services to coordinate
frequency usage.
– Change the SSID to a non-default setting (and
do NOT use ‘ufw’).
– Disable the SSID broadcasting capability.
Current Wireless Campus Coverage
(Spring 2002)