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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)