Technical Information Paper
The University of Tennessee
Ana Preston and Predrag Radulovic
Division of Information Infrastructure
Office of Research and Information Technology
The University of Tennessee
August 31, 2000
TABLE OF CONTENTSI. INTRODUCTION *
II. OVERVIEW OF EXISTING WIRELESS TECHNOLOGIES*
1. Voice and Messaging*
2. Hand-held and Internet-enabled devices*
3. Data Networking*
3.1 Wireless Local Area Networks*
3.2 Broadband Wireless*
4. Important issues for wireless technologies*
III. CURRENT PROJECTS AT UT KNOXVILLE CAMPUS*
1. Voice/Messaging Projects at UT*
2. Data Networking Projects at UT*
IV. FUTURE WIRELESS DEPLOYMENT ISSUES AT UT*
1. Cost Model*
2. Policies and Practices*
3. Technical Issues*
4. Creation of Wireless Working Group*
5. Customer Support and Education*
6. Industry Partnerships*
7. Relationship to VolNet Project*
Wireless technologies represent a rapidly emerging area of growth and importance for providing ubiquitous access to the network for the campus community. Students, faculty and staff increasingly want untethered network access from general-purpose classrooms, meeting rooms, auditoriums, and even the hallways of campus buildings. There is interest in creating mobile computing labs utilizing laptop computers equipped with wireless Ethernet cards. Recently, industry has made significant progress in resolving some constraints that have affected the widespread adoption of wireless technologies. Some of the constraints have included disparate standards, low bandwidth, and high infrastructure and service cost.
Wireless technologies can both support the institutional mission and provide cost-effective solutions. Wireless is being adopted for many new applications: to connect computers, to allow remote monitoring and data acquisition, to provide access control and security, and to provide a solution for environments where wires may not be the best implementation.
New technologies rapidly find acceptance in the university environment. To determine the appropriate application of wireless communication, the campus community will be fully engaged to ensure that this developing technology will be used to enhance the teaching, learning, and research environment. Communication with the LAN Managers, the IT Roundtable, Technology Advisory Board, Volnet Advisory Committee, Research Council, and other appropriate groups will be considered in planning for the successful implementation on campus. A number of pilot implementations are scheduled for Fall 2000. Based on data from the initial implementations and input from students, faculty, and staff, a specific roadmap will be developed for the expansion of wireless connectivity for the entire Knoxville campus.
This paper presents an overview of existing wireless technologies, current projects being deployed at UT, and an assessment of issues and recommendations for future deployment of wireless technologies at UT.
II. OVERVIEW OF EXISTING WIRELESS TECHNOLOGIES
There are numerous applications for each of the different wireless technologies. For the purposes of this paper, applications of wireless technologies are divided into the following: Voice and Messaging, Hand-held and other Internet-enabled devices, and Data Networking. Although a traditional classification, this way of categorizing wireless technologies also includes their differences in cost models, bandwidth, coverage areas, etc. Finally, a section is included on issues related to wireless technologies.
1. Voice and Messaging
Cell phones, pagers, and commercial two-way business radios can provide voice and messaging services. These devices may be based on analog or digital standards that differ primarily in the way in which they process signals and encode information. The analog standard is the Advanced Mobile Phone Service (AMPS). Digital standards are Global System for Mobile Communications (GSM), Time Division Multiple Access (TDMA), or Code Division Multiple Access (CDMA). Normally, devices operate within networks that provide metropolitan, statewide, or nationwide coverage. These large and costly networks are operated by carriers such as AT&T, Sprint, Verizon, local phone companies, etc. and operate in different frequency bands which are allocated by the FCC.
Throughput depends on the standard being used, but presently in the U.S., these networks provide throughput rates up to 16 kilobits per second (Kbps). New digital standards, also referred to as "Third-Generation Services" or 3G, are expected by 2004, and will provide 30 times faster transfer rates and enhanced capabilities.
Because of the many standards, there are interoperability issues between networks, carriers, and devices. Generally, charges are based on per minute utilization or per number of messages.
2. Hand-held and Internet-enabled devices
Internet-enabled cell phones and Personal Digital Assistants (PDAs) have emerged as the newest products that can connect to the Internet across a digital wireless network. New protocols, such as Wireless Application Protocol (WAP), and new languages, such as WML (Wireless Markup Language) have been developed specifically for these devices to connect to the Internet. However, the majority of current Internet content is not optimized for these devices; presently, only email, stock quotes, news, messages, and simple transaction-oriented services are available. Other limitations include low bandwidth (less than 14 Kbps), low quality of service, high cost, the need for additional equipment, and high utilization of devices battery power. Nevertheless, this type of wireless technology is growing rapidly with better and more interoperable products.
3. Data Networking
In this paper, we differentiate between pure data applications in (1) wireless local area networks (WLANs) and data, voice, and video converged in (2) broadband wireless. We also briefly discuss (3) Bluetooth, an emerging wireless technology.
3.1 Wireless Local Area Networks
Wireless Local Area Networks (WLAN) are implemented as an extension to wired LANs within a building and can provide the final few meters of connectivity between a wired network and the mobile user.
WLANs are based on the IEEE 802.11 standard. There are three physical layers for WLANs: two radio frequency specifications (RF - direct sequence and frequency hopping spread spectrum) and one infrared (IR). Most WLANs operate in the 2.4 GHz license-free frequency band and have throughput rates up to 2 Mbps. The new 802.11b standard is direct sequence only, and provides throughput rates up to 11 Mbps. Currently the predominant standard, it is widely supported by vendors such as Cisco, Lucent, Apple, etc. By the end of 2001, a new standard, 802.11a, will operate in the 5 GHz license-free frequency band and is expected to provide throughput rates up to 54 Mbps.
WLAN configurations vary from simple, independent, peer-to-peer connections between a set of PCs, to more complex, intra-building infrastructure networks. There are also point-to-point and point-to-multipoint wireless solutions. A point-to-point solution is used to bridge between two local area networks, and to provide an alternative to cable between two geographically distant locations (up to 30 miles). Point-to-multi-point solutions connect several, separate locations to one single location or building. Both point-to-point and point-to-multipoint can be based on the 802.11b standard or on more costly infrared-based solutions that can provide throughput rates up to 622 Mbps (OC-12 speed).
In a typical WLAN infrastructure configuration, there are two basic components:
- Access Points An access point/base station connects to a LAN by means of Ethernet cable. Usually installed in the ceiling, access points receive, buffer, and transmit data between the WLAN and the wired network infrastructure. A single access point supports an average twenty users and has a coverage varying from 20 meters in areas with obstacles (walls, stairways, elevators) and up to 100 meters in areas with clear line of sight. A building may require several access points to provide complete coverage and allow users to roam seamlessly between access points.
- Wireless Client Adapter - A wireless adapter connects users via an access point to the rest of the LAN. A wireless adapter can be a PC card in a laptop, an ISA or PCI adapter in a desktop computer, or can be fully integrated within a handheld device.
Wireless Client Adapter A wireless adapter connects users via an access point to the rest of the LAN. A wireless adapter can be a PC card in a laptop, an ISA or PCI adapter in a desktop computer, or can be fully integrated within a handheld device.
3.2 Broadband Wireless
Broadband wireless (BW) is an emerging wireless technology that allows simultaneous wireless delivery of voice, data, and video. BW is considered a competing technology with Digital Subscriber Line (DSL). It is generally implemented in metropolitan areas and requires clear line of sight between the transmitter and the receiving end. BW comes in two flavors: (1) Local multi-point distribution service (LMDS) and (2) Multi-channel multi-point distribution service (MMDS). Both operate in FCC-licensed frequency bands.
- 1) LMDS is a high bandwidth wireless networking service in the 28-31 GHz range of the frequency spectrum and has sufficient bandwidth to broadcast all the channels of direct broadcast satellite TV, all of the local over-the-air channels, and high speed full duplex data service. Average distance between LMDS transmitters is approximately 1.5 kilometers (1 mile) apart.
- 2) MMDS operates at lower frequencies, in the 2 GHz licensed frequency bands. MMDS has wider coverage than LMDS, up to 35 miles, but has lower throughput rates. Companies such as Sprint and WorldCom own MMDS licenses in the majority of U.S. metropolitan areas.
- Geosynchronous earth orbit (GEO) and low earth orbit (LEO) satellites represent yet a third vehicle for deploying wide-area braoadband wireless solutions. Several issues exist here that are not present in other tower-based Broadband solutions:
- The high cost of deploying the satellite infrastructure means that only a few key vendors will participate in this arena. Moreover, the pressure to recover initial capital costs will likely result in "winner take all" corporate mentality where standards, interoperability, and new customer features may take a backseat to cost recovery.
- Initial deployments represent proprietary technologies and any interoperability standards are three or more years away.
- Fewer GEO satellites, because of their distance from earth, are needed to cover a given region and therefore are less costly to deploy. The greater distance, however, requires a miniature satellite dish (one meter) for adequate signal collection thus making their use in mobile wireless applications impractical. LEO satellites, because of their lower earth orbit and stronger signal strength, are necessary for use in mobile applications where antenna size is a factor.
Whether it is tower-based or satellites, bBroadband wireless still involves costly equipment and infrastructures. However, as it is more widely adopted, it is expected that the service cost will decrease and functionality will improve..
Bluetooth is a technical specification for small form factor, low-cost, short-range wireless links between mobile PCs, mobile phones, and other portable handheld devices, and connectivity to the Internet. The Bluetooth Special Interest Group is driving development of the technology and bringing it to market. It includes promoter companies such as 3Com, Ericsson, IBM, Intel, Lucent, Motorola, Nokia, and over 1,800 Adopter/Associate member companies.
Bluetooth covers a range of up to ten meters in the unlicensed 2.4GHz band. Because 802.11 WLANs also operate in the same band, there are interference issues to consider. Bluetooth technology and products are not expected until the end of 2000. At that time and if Bluetooth becomes an adopted technology, current WLANs will already be migrating to the 5 GHz band.
4. Important issuesIssues for wireless technologies
As with any relatively new technology, there are many issues that affect implementation and utilization of wireless networks. There are both common and specific issues depending on the type of wireless network. Some of the common factors include electromagnetic interference and physical obstacles that limit coverage of wireless networks, while others are more specific, such as standards, data security, throughput, ease of use, etc.
- A major obstacle for deployment of wireless networks is the existence of multiple standards. There are both analog and digital standards in wireless telephony. While GSM is the only widely supported standard in Europe and Asia, multiple standards are in use in the U.S. As a result, the U.S. has lagged in wireless network deployment. Just recently, organizations have been formed to ensure network and device interoperability. For example, the adoption of the 802.11b standard has made wireless data networks one of the hottest newcomers in the current wireless market.
- Another issue is coverage. Coverage mainly depends on the output power of the transmitter (FCC regulated), its location and frequency used to transmit data. For example, lower frequencies are more forgiving when it comes to physical obstacles (walls, stairways, etc.), while high frequencies require clear line of sight. For each particular application, throughput decreases as distance from the transmitter or access point increases.
- Data security is a major issue for wireless due to the nature of the transmission mechanism (electromagnetic signals passing through the air). It is commonly believed that voice applications are less secure than data applications. This is due to limited capabilities of existing technologies to protect information that is being transmitted. For example, in metropolitan areas, users are at risk that simple scanning devices can highjack cell phone numbers and be maliciously used. In WLANs, authentication and encryption provide data security. Current security implementations include:
- MAC (Ethernet) address-based access lists on access points, where only registered and recognized MAC addresses are accepted and allowed to join the network.
- A closed wireless system, where users have to know the non-advertised network name to be able to join.
- RADIUS server based authentication, where users are authenticated against a centralized RADIUS server based on their MAC address or their username and password.
- Wireless Equivalency Privacy (WEP) utilizes data encryption with 40-bit or 128-bit keys that are hidden from users. WEP provides three options, depending on the level of security needed: no encryption of data, combination of encrypted and non-encrypted data, and forced data encryption.
In WLANs, data is encrypted only between the wireless adapter and the access point. Data travels through a wired LAN unencrypted. Therefore, data transmitted by wireless is not more secure than data transmitted through the wire, but probably not less secure. Application level encryption mechanisms, like secure web transactions (SSL), SSH, etc. are responsible for further protection of data.
III. CURRENT PROJECTS AT UT KNOXVILLE CAMPUS
1. Voice/Messaging Projects at UT
Knoxville metropolitan area
- In partnership with Cricket Communications, goal is to provide pre-paid, flat rate cell phone service to UT.
- Service does not currently include long distance service
- No roaming and interoperability with other cell phone carriers and services
Undergoing installation of five towers on the Knoxville Campus.
By November 2000: coverage for entire city
Verizon: UT Virtual Private Network (VPN)
- Wide-area transmission network to be available and accessible exclusively by UT constituents.
- Service will include unique five-digit phone numbers for staff
- Web-enabled phones
Under development by Telephone Services
- Two-way packet radio network with a private ID block of 20,000 phone numbers allocated to UT.
- Flat-rate service fee
Operational since June 2000
Within a building
- For specialized voice-based indoor applications.
- Currently being considered for the Knoxville Veterinary Hospital (and also the Tullahoma campus).
- SpectraLink phones allow roaming and may replace pocket-pagers
- Phones are 802.11 compliant.
Currently testing and evaluating phones and their incorporation into WLANs
Table 1. Voice and Messaging Projects at UT
2. Data Networking Projects at UT
During Spring 2000, DII evaluated 802.11b standard-based WLAN products from several vendors (: Cabletron, Apple, Cisco/Aironet and Lucent) were evaluated. The general policy is to take advantage of the latest technology that is fully compliant with industry standards. All wireless communication must be capable of authentication utilizing the Radius authentication standard. Based on cost, the Operating Systems platforms supported, upgradeability and return on investmentand upgrade path, the Lucent Orinoco access points and wireless client adapters have been selected for initial implementation in pilot projects for Fall 2000. Forty40-bit encryption, the closed wireless network mechanism, and MAC-based RADIUS authentication will protect data. The new line of Lucent products (AS2000) is expected by the first quarter of 2001. UT has been selected along withamong four other institutions (University of Pittsburgh, University of Michigan, University of Minnesota, and Penn State University), to be part of Lucents AS2000 testing program. This will occur during Fall 2000.
Current projects utilize 44 Lucent access points and it is expected that by Spring 2000, final recommendations on these and other vendor/products and wide utilization of WLANs on the Knoxville campus will be made. The following table contains all current WLAN projects at UT.
Computer Science (CS) Claxton
Whole Entire building
- Augmentation of intra-building network to service needs for CS faculty and students
August 23, 2000
Information Science (IS) Temple Court
Whole Entire building
- To explore costs and benefits and the impact on students, faculty, and IS curriculum.
- To assess the impact of wireless technology on skill development, its use in the classroom, and to better evaluate IS curricular needs, by means of comparison study between 15 students with wireless-ready laptops and 15 without them.
August 23, 2000
UT Hodges Library and Information Science
Four4 locations: Reference, Periodicals, Reserve, Stacks (Z)
- To complement the School of Information Science wireless initiatives
- To study wider-deployment of wireless in the library for faculty and students
August 23, 2000
Business - Glocker
Two classrooms and one common area
- To provide wireless access to first-year MBA students.
Installation of access points: August 23, 2000
Human Ecology Jesse Harris
- To provide mobile access point for classroom use for faculty research project
Completed: June 15, 2000
Division of Information Infrastructure (DII)- Dunford
Third, Fourth and Fifth Floors
- To deploy a production test environment for DII staff
Test environment (3rd/4th floors) operational since June 1, 2000
- To deploy a production test environment for DII staff
August 23, 2000
Art and Architecture
- To deploy a test environment for Apple laptops
September 11, 2000
Student Services Black Cultural Center
In and outside the Within building
- To augment backbone connectivity and allow roaming between areas within and within around the building, e.g., the outdoor courtyard
Pending construction of building
Table 2. Data Networking Projects at UT
In addition, UT is currently considering a point-to-multi-point wireless solution to possibly connect locations such as Fraternity Park and the Agriculture Campus to the campus backbone.
IV. FUTURE WIRELESS DEPLOYMENT ISSUES AT UT
As new wireless technologies continue to emerge, it is critical that UT continuously evaluate, test, and deploy wireless pilot programs based on assessment of current benefits and expected future developments. In addition to general issues for wireless technologies deployment, there are specific issues that affect wireless deployment at UT.
1. Cost Model
Deployment of wireless networks will require review of the current model for recovering networking costs. Currently, the port-based cost model assesses a fee for all activated ports. As the user community becomes increasingly mobile, a user-based cost model based on connectivity per deviceperson, not per port, must be implemented. A user may employ a variety of devices: a wired desktop in the office, an IP-based telephone, a wireless laptop in the library, a wireless PDA on the campus, and others. Services to a user must be based on the functionality required, not the physical port, and the cost model must reflect this.
2. Policies and Practices
As with any new technology, establishment of new policies and best practices is essential for the success of wireless initiatives. Primarily for voice-based applications, cooperation and coordination with service providers is needed to ensure complete coverage in the designated area, as well as to provide satisfactory density and the highest network throughput. For all license-free solutions, such as WLANs, point-to-point and point-to-multi-point solutions, the Division of Information Infrastructure (DII) will maintain administrative and technical responsibility. If not centrally managed, wireless networks set up independently by departments or privately, can potentially limit accessibility and quality of service on campus.
Several issues arise in particular for WLAN deployment on campus. These issues require immediate attention. To allow seamless roaming between network subnets, similar to the way that cell phone users roam between networks, new technical solutions need to be implemented. Some of these include Dynamic Host Configuration Protocol (DHCP), dynamic Domain Name Services (DDNS), mobile/wireless Internet Protocol (IP) solutions, etc. Some of these solutions such as DHCP are already being implemented as part of the VolNet project, but some new ones may need to be considered. Furthermore, RADIUS authentication servers will need to be deployed and interfaced with the current LDAP-based directory service in order to provide universal authentication for all campus constituents.
Wireless Task Force
A DII Wireless Task Force with representation from Network Services, Telephone Services, and Customer Technology Support will continue to provide leadership in the wireless projects. External rRepresentatives will be included from academic, research and administrative units, as well as from external organizationsas appropriate.
Customer Support and Education
As with any campus technology, Customer Support Services will need to include wireless support, from technical to administrative. The following are some short-term issues that will be addressed for customer support:
- Creation and ongoing maintenance of wireless support web pages within the DII web site. This web space will provide status of current UT projects, reference materials, how-to guides and policies.
- A series of Wireless Seminars will begin in Fall 2000, where discussion of scenarios of use, demonstrations, and pilot project presentation(s) will take place.
6. Industry Partnerships
UT will seek relationships with vendors working on wireless technologies. The Lucent partnership illustrates how UT can leverage vendor relationships to support the universitys mission. By becoming one of five universities in the country that will test Lucents next generation of WLANs products, UT will not only benefit from this leadership position, but will also be utilizing the latest technology.
Partnership opportunities will be sought with other vendors as appropriate, such as Apple, Cisco, Dell, IBM and others.
The adoption of WLANs and other wireless technologies at UT does not preclude the requirement for the extensive wired network to be provided by the VolNet project. Wireless technologies are complementary to the VolNet project and can also provide cost-effective solutions for specific implementations and new functions.
Specific implementations, as well as the scope and goals of wireless deployment at UT, will need to be addressed by the campus. UT must strategically decide how to efficiently make use of wireless technologies in accordance with the universitys mission.
Sources:www.wlana.com, www.itcom.itd.umich.edu, and www.geckobeach.com/cellular/intro/glossary.htm
AMPS: Advanced Mobile Phone Service, commonly known as analog cellular. AMPS offers limited battery life, poor sound quality, and has a much higher power output rate than the newer digital phones. Available only in the 800 MHz frequency band.
Access Point: A device that transports data between a wireless network and a wired network infrastructure. Also referred as base station.
Bluetooth: a technology specification for small form factor, low-cost, short-range wireless links between mobile PCs, mobile phones, and other portable handheld devices, and connectivity to the Internet. The Bluetooth Special Interest Group (SIG) is comprised of over 1,800 Adopter/Associate member companies. Bluetooth technology and products are not expected until the end of 2000.
Broadband: Also called wideband. Transmission facility whose bandwidth is greater than that available on voice-grade facilities.
CDPD: Cellular Digital Packet Data. Wide area data network which takes advantage of exciting AMPS cellular network by transmitting data packets on unused voice channels.
CDMA: Code Division Multiple Access. CDMA differs from GSM and TDMA by its use of spread spectrum techniques for transmitting voice or data over the air. Available in either 800 or 1900 MHz frequencies.
DSL: Digital Subscriber Line. A data distribution service that utilizes POTSPlain Old Telephone Service. Provides Mbps throughput rates.
DSSS: Direct Sequence Spread Spectrum. A spread spectrum modulation that divides the 2.4 GHz band (83 MHz wide) into three 24 MHz channels. One wireless LAN uses one channel. Each bit of data fills the channel with multiple frequencies. More complex than Frequency Hopping, but semiconductor improvements have reduced the cost.
DNS: Domain Name Server. The Domain Name Service is simply a two-way translation between IP name and IP address (e.g. the IP namewww.utk.edu corresponds to the IP address 22.214.171.124). Dynamic DNS is a more complex service and it is usually updated regularly by DHCP servers.
DHCP: Dynamic Host Configuration Protocol. A protocol for assigning dynamic IP addresses to devices on a network.
Electromagnetic (EM) waves: Commonly characterized by their frequency (radio waves, infrared, ultra-violet, visible light, microwaves, etc.)
FCC: Federal Communications Commission. The Government agency responsible for regulating telecommunications in the United States. The agency is located in Washington, D.C.
FHSS: Frequency Hopping Spread Spectrum. A spread spectrum modulation that divides the 2.4 GHz band (83 MHz wide) into 79 hops, each 1 MHz wide. Every 0.4 seconds the transmitter hops to the next frequency determined by a pseudo-random sequence. Multiple channels, each creating a separate wireless LAN, are created with up to 15 different hopping sequences.
GSM: Global System for Mobile Communications. The most common digital cellular system in the world.
IEEE: Institute for Electrical and Electronics Engineers. A membership organization that includes engineers scientists and students in electronics and allied fields.
IP: Internet Protocol. A method or protocol by which data is sent from one computer to another on a network, i.e. the Internet. Each computer has to have a unique assigned 32-bit IP address.
LDAP: Light Weight Directory Access Protocol. A protocol designed for accessing online directory services.
LMDS: Local Multi-point Distribution Service. This service can provide two way digital communication. Applications of LMDS include voice, video, and high-speed data communication. The bandwidth of LMDS is more than twice the total bandwidth of
AM/FM radio, VHF/UHF TV, and cellular telephone combined.
MAC address: Media Access Control address. A unique hardware identifier. On Ethernet, it is the same as Ethernet address.
MMDS: Multi-channel multi-point distribution service. It operates at lower frequencies, in the 2 GHz licensed frequency bands. MMDS has wider coverage than LMDS, up to 35 miles, but has lower throughput rates. Companies such as Sprint and WorldCom own MMDS licenses in the majority of U.S. metropolitan areas.
PCS: Personal Communication Services. PCS and cellular are sometimes interchanged.
POTS: Plain Old Telephone Service Standard. Plain wired, telephone service.
RADIUS: Remote Authentication Dial-In User Service is both a software program and a detailed communications protocol. Its primary function is to allow front-end authentication and then authorize access based on multiple criteria.
Roaming: Movement of a wireless client between two access points or cells. Roaming usually occurs in infrastructure networks built around multiple access points.
Spread Spectrum: Radio frequency modulation that spreads the radio energy across a wide frequency spectrum, reducing the power at any one frequency. This is used to reduce interference and make eavesdropping difficult. Spread spectrum is a required modulation in the 2.4 GHz band, by FCC rules.
Subnet: A part of the network. Computers on the same subnet have a specific number of leading bits in their IP address that are fixed (same). Geographically distinct locations usually belong to different subnets.
TDMA: Time Division Multiple Access. Divides frequency bands available to the network
into time slots, with each user having access to one time slot at regular intervals. Available in either 800 or 1900 MHz frequencies.
WAP: Wireless Access Protocol.
WEP: Wireless Equivalency Privacy. A standard that defines encryption mechanisms for data transmitted in WLANs.