Wireless Community Networks

A Guide for Library Boards, Educators, and Community Leaders

by Robert L. Williams

Texas State Library and Archives Commission Library Development Division 1999 This guide may be duplicated (in print or electronic form) freely for non-profit or educational purposes.

The guide is available online in Portable Document Format (PDF) and HTML formats. The latest revisions will be available at the following location: http://www.tsl.state.tx.us/LD/Publications/Wireless/

TSLAC Cataloging in Publication Data:

Williams, Robert L. Wireless community networks : a guide for library boards, educators, and community leaders / by Robert L. Williams. – [Austin, Tex.] : Library Development Division, Texas State Library and Archives Commission, 1999 129 p. : ill. ; 28 cm.

1. Wireless communication systems 2. Computer networks 3. Wide area networks (Computer networks) I. Texas State Library and Archives Commission. Library Development Division. II. Title.

Comments or complaints regarding the programs and services of the Texas State Library and Archives Commission can be addressed to the Director and Librarian, P.O. Box 12927, Austin, Texas 78711-2927, 512-463-5460 or 512-463-5435 fax. Wireless Community Networking

A Guide for Library Boards, Educators, and Community Leaders

Table of Contents

Acknowledgements ...... v

Introduction...... 1

Part I. Putting the Pieces Together 1. The Need for Community Networks ...... 9 2. Where Wireless Connectivity Fits In...... 21 3. Budgeting for Wireless Connectivity ...... 33 4. Where to Go Next ...... 53

Part II. Understanding the Concepts 5. Data Transfer Rates: A Primer...... 57 6. Building a Local Area Network ...... 63 7. WANs, MANs, and the Internet...... 73 8. How RF Wireless Connections Work ...... 89 9. Sharing Without Sacrificing: Securing Wireless Networks ...... 105

Part III. Appendix A. Glossary ...... 113 B. RF Wireless Equipment Manufacturers ...... 119 C. Other Resources ...... 123 D. Comment Form...... 127

Colophon ...... 129

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Acknowledgements

I would like to thank several people without whom this guide would not have been created. First, a big thanks to Bob Gaines, Automation Consultant at the Central Texas Library System, who was the catalyst in getting the project started. Without Bob, my interest for wireless connectivity would have remained indefinitely in a-conversation-over- lunch mode.

Biggest thanks go to my family, who sacrificed a great deal during a period of about four weeks while I hammered out the more difficult parts of the guide. My wife and children had to deal with a husband and a father who was home but not really present. To Nancy, Nic, and Tessa I say thanks for the time.

I also greatly appreciate the time of several individuals who contributed answers to questions and product pricing at crunch time. Kenna Nevill, at National Business Group in Dallas, provided detailed information which helped me in pricing the budget items presented in Chapter 3. (I’m sure she’d be glad to talk to you as well. You can reach her at 972-490-6249 or [email protected]) Three other vendor representatives also contributed pricing information: Kelley Spitzer, sales contact at C-SPEC Corporation (800-462- 7732 x212, [email protected]); Terry Lafferty, Territory Sales Manager for Solectek (630-980-6144, [email protected]); and Jim Bowie, Account Manager at BreezeCom (760-431-9880 x136, [email protected]).

A special thanks goes to Jeanette Larson and Christine Peterson at the Library Development Division of the Texas State Library and Archives Commission, who agreed to publish this work if I could get it done. Thanks for the opportunity to write it.

Last, thanks to the production staff who worked diligently to get it out the door.

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Introduction

Welcome to the world of computer networking!

For many of us, the need to know about computer networks has come about very quickly. In 1995, legislation passed in Texas provided for great savings on high-speed data circuits for public schools, libraries, and telemedicine centers. In 1996, federal legislation was passed creating a “universal service fund” to assist rural, impoverished school districts and libraries defray the cost of connecting to the Internet. Technology Integration in Education (TIE) grants have been issued from federal funds, and Telecommunication Infra- structure Fund (TIF) grants have been issued from state funds. New legislation is being passed and implemented almost too quickly to keep up. Technology is being deployed at an unprecedented rate.

Whew! I’m tired already just thinking about it!

The driving force behind almost all of this frenzy? The Internet. Or at least the perceived potential the Internet provides.

Potential of the Internet

Since 1992, President William Clinton and Vice President Al Gore have proposed a vision for our educational system: information resources available to all students, poor as well as rich, communication to points around the world and Internet connectivity throughout the country. To some degree the hype regarding the Internet has been difficult to keep pace with since the world wide web’s graphical introduction to the world in 1994.

But the potential is great. Such connectivity may well represent a fundamental shift in how our society provides many services in the fields of libraries and education. In addition, it may also alter how we provide community

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services. It may alter how we as public entities communicate with our constituents. It will certainly accelerate our shift from a cash-based society to one based on “electronic cash.” Many interesting services and opportunities will be possible.

Pitfalls

But using the Internet to provide services is not a bed of roses. Along with the promise and potential of network connectivity come serious pitfalls as well. A continued, perhaps accelerated shift to private education, or at least distributed education, is likely. What problems and additional burdens will that place on our already strained education system? The need to provide up-to-date, acceptable levels of library service will increase. It will be The push to provide problematic to serve those without Internet access at home. A greater divide between the technologically rich and the Internet access as a technologically poor may occur. Some privacy will be lost. core element of school Chief among all the pitfalls, however, is the simple cost of maintaining a technological infrastructure. In the future, and library services even more computers will be required. More personnel with technical expertise will be required to maintain equipment has come extremely and software, either as paid staff or contracted services. More and more frequent technical training for staff will be quickly for policy required. Equipment, which in many cases is acquired makers. through grants, must be repaired and eventually replaced. All of this technological advancement comes at a time, of course, when taxpayers are becoming more and more reluctant to increase their tax burdens. With costs rising, and sources of funding becoming more constrained, how will we walk the fine line of providing access to the best technology to all Americans without creating fiscal chaos in other areas of our budgets?

Need for This Manual

The push to provide Internet access as a core element of school and library services has come extremely quickly for policy makers. Before 1994, almost no one knew about the Internet. Only a highly visionary few thought about it as a matter of public policy. But when its text-based face gave way to graphical interfaces in 1994, and its government-

2 Library Development Division Introduction

sponsored nature gave way to commercialized access in 1995, enterprising companies began molding their visions into real software products. Suddenly, everyone was having visions of Internet grandeur.

The Internet is seen as a boon to education and information provision. Regardless of how real its usefulness is at the moment (and in some cases it usefulness is very high), the political pressure is on to get connected. Get connected or be left behind seems to be the attitude of the day. But at what cost and to what end?

Planners and decision-makers in libraries and schools have hardly had time to catch their breath. They’ve had even less time to analyze current connectivity options and make Planners and choices regarding the best connectivity for their communities. And many vendor sales representatives and volunteer decision-makers in consultants, though well intentioned, have provided incomplete or inaccurate advice regarding best methods of libraries and schools connectivity. As a result, in many cases grant writers have specified equipment and Internet connectivity that is either have had even less under-powered or costs too much. time to analyze So, what are the options? Are there ways to maximize infrastructure development and minimize the fiscal burden current connectivity on public entities when grant funding is exhausted? What connectivity options are available? Can radio frequency options and make wireless connectivity help public entities manage network costs, especially in remote rural Texas communities? choices regarding the best connectivity for Purpose their communities. Wireless networking can play an important role in minimizing ongoing costs of network connectivity while maximizing its potential benefit. At this point, community networking itself has received little attention. Using wireless connectivity to develop base level networking has received even less. Few grant consultants are discussing community infrastructure and even fewer are aware of the availability of wireless networking. Representatives of local exchange companies (your local telephone company) are naturally in the business of selling wired phone and data service, and so they are unlikely to discuss wireless networking options.

Therefore, this guide offers a beginner’s look at wireless connectivity in the context of community networking.

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Wireless connectivity is not the best solution in all cases or in all communities. However, for many communities it will provide a sensible introduction into the world of community infrastructure.

A secondary purpose of this guide is to provide basic information to local community leaders about computer networking in general. Armed with a basic understanding of computer networks, leaders can make adequate budgetary preparations and determine the direction of future network growth.

Audience

As the title indicates, the guide is written for non-technical community leaders:

This guide offers a ¨ members of public library boards ¨ directors of public libraries beginner’s look at ¨ members of public school boards wireless connectivity ¨ public school administrators and teachers ¨ city managers and county judges in the context of ¨ city councils and county commissions ¨ other interested community members and volunteers community network- It is our hope that the guide is informative and easy to ing. understand. It assumes no knowledge of computers or computer networks.

Organization

The guide is organized into three main parts: an administrative section, a technical section, and a series of appendices. The administrative section is the primary content of the manual, with information on the benefits of community networking, how wireless networking can help achieve those, and what is required to budget appropriately for wireless connectivity. The technical section goes into fuller detail about how networks are built and how the components of a wireless connection work. The appendix provides auxiliary information.

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Comments

Knowing that time is scarce for staff in all public entities, we have attempted to make the guide as clear and succinct as possible. To this end, we have provided a comment form at the end of the guide. Please take a moment when you are finished and let us know how we did. What are the guide’s strengths and weaknesses? Where is it complete and where is it over- or under-developed? Your feedback will help us make revisions in any future editions that may be distributed.

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Part I. Putting the Pieces Together

In this section we identify the need for and benefits of community-wide computer networks, the components required, and the scenarios in which wireless connections are effective. We also discuss the budget implications of wireless connectivity.

Preliminary Definitions

Data:

In this manual, data refers to any type of information transmitted across a computer network from one machine to another: word processing files, database records (like patron records, student grades, or customer billing records), card catalog information, pictures, sounds, or even just keystrokes.

Telecommunications:

Telecommunications is the process of communicating over telephone wires, either by voice conversation or computer networking. The term also describes equipment used in the communication process, such as telephones or network devices. Telecommunications is commonly used to describe all communication links—even those that don’t use wires.

Community networks:

In this manual, community network refers to the equipment and telecommunications components making up a community-wide computer network. Other books and articles may use the term to mean a centralized repository of information about a community’s organizations or services.

Texas State Library and Archives Commission 7 8 Library Development Division CHAPTER ONE The Need for Community Networks

They’re everywhere!

Computers have become part of the normal office landscape over the past fifteen years. Many office functions have been converted from paper to electronic form. Centralized databases have been created. Computer networks have been developed so that users at one computer can store and retrieve data on another computer in a centralized area. This centrally stored data can be shared among multiple computer users. And, with more and more citizens having access to computers at home, such informational databases are being made available to individuals and other agencies outside the organization as well.

As a result of this adoption of technology, less staff is required for routine clerical tasks like filing and retrieving central files. But more knowledge is required of existing staff. Knowledge of basic computer operation, word processing, and spreadsheet software is required. Also, more staff or contracted assistance is required to maintain these computers and networks.

As one looks at the balance sheets showing increasing expenditures for computers, networks, and Internet connectivity, one might wonder whether all of this technology is really beneficial. What benefits are provided? Table 1 on the next page lists some of the present and future benefits computer technology provides to the two most common information-related entities in a community: the public schools and the public library.

With the need to incorporate technology into public services fairly established, the discussion is shifting to the best way to fund such technology-based services. Current budget levels may not adequately support all the technology we

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currently use. So how can we minimize increasing costs and maximize the effectiveness of revenues already collected from the community and other state and federal sources?

Table 1. Benefits of Computer and Network Technology

¨ In schools, computers and computer networks: § provide a means of educating students in computer use (office skills and technical support) for future workforce development § support a computer science curriculum § provide effective access to electronic materials § support instruction with drill and practice and role-playing exercises § facilitate student record management § facilitate communication among teachers, administrators, and school staff § provide a means of professional communication among colleagues § may reduce clerical tasks (for teachers and administrative staff) § may facilitate communication between the school and the community § may provide a means of extending the classroom to remote areas, such as the home

¨ In public libraries, computers and computer networks: § provide control over materials (automated library system), including overdues, inventory, and collection development § provide effective access to electronic reference materials § provide access to a wide variety of information resources over the Internet § may reduce clerical tasks § may provide access to computer services for those without computers at home § may provide a means of extending information services to remote areas, such as the home

In the past, municipal, county, and state governments have functioned independently—most of their functions were carried out without regard to the functions of other entities. As we use technology more often to enhance and expand our governmental services and operations, however, one of the primary answers to the rising cost of providing technologically-based services lies in finding common needs for infrastructure and sharing as many as possible.

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Common Infrastructure in a Computerized Age

How would it be if each of us had to build a road from our house to the center of town just so we could travel back and forth to work every day? We would have to drive down- town and then back up the proper road to get to our job site. (My, my, what a traffic circle in the middle of town!) And we would each have to pay to have our individual road maintained.

Someone in the past decided that it’s better to build common infrastructure. Everyone puts a little money into a common pot to have a single road built. Then each of us pays the smaller expense of building just a driveway from the garage to the road. In the end, we can drive anywhere in the community in less time, with less congestion, and for less total cost. In contemporary terms, it’s a “win-win” situation.

This approach to cost effectiveness and convenience was later applied to national travel. In the 1950s President Dwight Eisenhower commissioned an interstate highway system spanning our country. Its primary purpose was to provide an effective means of quickly deploying military equipment and personnel in the event of a war. It also provided benefits to citizens traveling across the country.

Rather than build separate highways from, say, Dallas, directly to other major cities—Los Angeles, Seattle, Chicago, Cleveland, New York City, Washington, DC, and Atlanta—a series of shorter, interconnected highways were built among all the cities. While it is not possible to travel directly from Dallas to New York City, it requires only slightly longer to travel several interconnected links to get there. And the cost of building the shorter, fewer links is much more economical. Not only that, but redundancy is built into the system. It is possible to travel multiple paths from Dallas to New York City. If one highway is destroyed—as in a war— an alternate route is available. Forty years later it’s still an effective plan. The interstate highway system is growing.

Which leads us back to the Internet. The interstate highway system became a model for the national data communications system the Department of Defense needed for its research and defense sites. Computer use was in full swing in the late 1960s and a network linking computers and

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computer users at the various supercomputer sites was needed. By 1987 the network, then under the administration of the National Science Foundation, grew to have 13 primary connection points. Once again, the idea of redundancy was part of its design. If the link between two points was broken, in an act of war or by some other means, the two points could still communicate over an alternate route. This network of computers became a “highway system” for computer data. Other university and research sites connected to one of the thirteen. The network became known as the Internet and the primary network circuits became known as the Internet backbone. For 30 years the Internet has grown until today it spans the entire globe. Common infrastructure is still an effective plan.

As we think of So, as we think of connecting the public agencies in our communities to the Internet, why would we think of connecting the public building separate roads to the Internet for each agency? Yet, that is our current mode of operation. City offices, for agencies in our administrative, police, and other operations, get one connection. County offices get another connection. The communities to the public school district gets another. And the public library gets a fourth. Some larger communities also have state- Internet, why would supported colleges or universities which also have an we think of building additional connection. separate roads to the The Need for Sharing Internet for each I have an eight-year-old son with a lot of toys. He has a agency? problem with sharing. Of course, he has a father who has a lot of toys as well. His father also has a problem with sharing. Sharing is okay as long as we’re sharing someone else’s stuff. It’s a little more difficult when we have guests and need to share our stuff. Organizations like city and county governments, school districts, and colleges have similar problems. It’s difficult to think of sharing our stuff with other agencies, mainly because the constituencies are so different.

All these agencies are generally supported by local, state, and federal tax dollars. As stewards of public funds, we should all make a concerted effort to minimize the cost and maximize the potential use of technology in our organizations—especially when one considers the fact that none of us has enough funding to do everything we need or would like to do anyway.

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Developing a shared network infrastructure among all public entities is a reasonable joint venture. A shared infrastructure makes possible the sharing of services as well. For example, where informational databases are required— in public libraries, school libraries, and college/university libraries—some database subscriptions would be of interest to all entities. Rather than subscribe to them separately, a joint subscription could be purchased. Remote access to the databases could be provided to city and county government offices as part of the process. The cost of such subscriptions will usually be lower when taken collectively rather than individually, plus the scope of access could be increased. But shared services are not the only benefit.

Infrastructure means more than the cabling and equipment that connects computers to form a network. It includes the technical personnel required to maintain the network. And Shared infrastructure it includes the staff skills required to make the best use of the computer resources. Developing a community-wide makes possible the network also offers the opportunity for public entities to share personnel resources. While a small city government sharing of services as or a small school district might find it impossible to have a network administrator/technician on staff, two or more well. It also includes entities can share the cost. When looking at the total each organization has budgeted for contracted network the technical per- technicians, paid at much higher costs per hour, the aggregate is generally enough to hire full-time personnel. sonnel required to This potential benefit in sharing personnel increases as maintain the net- more public entities are involved. The cost of training staff can also be shared. work. Can problems arise when sharing personnel? Absolutely. These problems are aggravated when sufficient planning and honest evaluation of needs is not provided. It’s that sharing problem again. If a staff person is directly hired by a college, for instance, and is also charged with providing training to local school district and municipal employees, the tendency for the college might be to slight the others. Making a shared system work requires advance planning, clearly stated needs and priorities, and a sense of selflessness. It requires an attitude of “we’re in this together” rather than “we’re in this to see what we can get out of it.”

Such sharing requires an adjustment in our institutional thinking. But it sets up the potential for maximizing the benefit of taxpayer dollars already being spent. And, in

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today’s environment, the perception of efficient expenditure of current funding may be required before future funding increases are approved.

Shared Internet Connectivity

As you examine the benefit of deploying a community network in order to maximize your community’s expenditure on technology, Internet connectivity will probably be the first object of collaboration. Is it really necessary for three of four publicly funded entities to have separate Internet connections? To be honest, there are reasons to have separate network connections in place. Most of the valid reasons have to do with security. Do we really want to have a situation where a high school student, or a library patron, might break into other agencies’ computer systems Security measures and alter, steal, or destroy privileged information?

must be put in place This is a scary argument that some present to justify separate connections. But it does not present a complete to protect electronic picture. To be completely honest, threats to network information are present when any organization connects to resources whether the Internet. Not only that, but current studies indicate that the threat to network information is just as great the agency is sharing locally from employees having access to the network as it is from hackers outside the organization. a network connection Security measures must be put in place to protect elec- or not. tronic resources whether the agency is sharing a network connection or not. Therefore, the issue might be more effectively looked at as a “what is the best way to secure all network resources against potential threats?” Once again, shared networks generally provide access to shared expertise. Hiring a certified professional may be possible when done collectively. This may provide a more secure networking environment than one supported by a single agency. Security is discussed further in Chapter 9, “Sharing Without Sacrificing: Securing Wireless Networks.”

How Sharing is Beneficial

Working together to provide common Internet access has real benefits. These are derived primarily from the nature of Internet connectivity. Each applies to a slightly different

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network configuration. Here is a short list, with descriptive examples:

¨ cost effectiveness ¨ increased bandwidth ¨ reliability/redundancy

Cost Effectiveness. The Internet is a network that is characterized by momentary bursts of traffic followed by periods of low activity. As the world wide web has grown, this characteristic has increased. When a user requests a web page, there is a small request packet sent across the Internet. Then there is a delay while the computer at the other end processes that request. Traffic is fairly steady while the web page’s text and images are downloaded. On a high-speed network connection, this occurs very quickly if the Internet itself is not congested. Then there is a relatively When a school long period of time when the user does nothing on the network, taking a minute or two to view the page that was district in a small, just displayed. rural community Because of this characteristic, a high-speed Internet connection can support hundreds of users at the same time. installs a high-speed Pages for some users are fetched while other users are reading their pages. When a school district in a small, rural data circuit for community installs a high-speed data circuit for Internet connectivity, much of the potential of the line is unused. Internet connectivity, Classroom instruction takes up much of the school day. This situation involves a data circuit that is underutilized. much of the potential

Another feature of Internet connectivity is that a few of the line is unused. computers can be added to a high-speed link with very little impact on the existing users. With an underutilized link, adding a few more users results in almost no difference in the download times of web pages for existing users. Even on a fully utilized link, adding a few users adds only a minor delay in the reception of web pages by existing users.

If the school district has an underutilized high-speed connection to the Internet, and the local public library also pays for Internet connectivity through a separate, generally much lower-speed Internet connection, one can say the community is over-committing its resources.

If the school district and the public library cooperate, the few library computers can be added to the school’s high- speed connection without significantly affecting the

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performance seen on school computers. If the connection between the school and the public library is over a wireless network connection, then there is no additional monthly expense incurred for the public library Internet connection. (For more budgetary details, see Chapter 3, “Budgeting for Wireless Connections.”) The fees the library was paying can be used to defray the cost of the school’s connection, spent on maintaining its wireless connection, or be reallocated to increase other library services. This, of course, depends on the nature of the cooperative spirit between the two entities.

In this scenario, community funds are spent more pro- ductively, so that costs are minimized and the existing resource is better utilized.

For an example of how a school district might be able to use The few library com- wireless connectivity to extend a high-speed connection to all of its campuses, see “Scenario #2,” on page 45. This puters can be added example also includes the public library as a remote site. to the school’s high- Increased Bandwidth. Another scenario involves the benefits of sharing two or more high-speed Internet speed connection connections. Let’s say the school district and the local community college were interested in maximizing the without significantly benefit of their connections. affecting the perfor- First, if both organizations regularly utilize over half the mance seen on school bandwidth of the individual connections, sharing a single connection will probably not be an option. However, the computers. entities can still benefit from sharing. By creating a third connection between the two entities, the two separate connections can be shared. If one connection becomes saturated with traffic, excess traffic can be rerouted to the other link. This effectively provides more bandwidth to both entities at peak usage levels. But this is not the only benefit of two sharing disparate connections.

Reliability/Redundancy. When two separate connections are available, and one of the connections fails for any reason, all traffic can be routed across the other connection. This concept can be extended further if each entity uses a separate Internet Service Provider. If one bandwidth—commonly used to Internet Service Provider experiences technical difficulties indicate how much, or how fast, and its service is unavailable, another link is available to data can be transmitted across a route traffic. Just as in the original Internet design, this telecommunications line or network connection in a period of redundancy provides for a more reliable service. Existing time, usually one second. resources are used more effectively.

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Each of these techniques ensures that the cost of providing Internet connectivity is minimized and that the effectiveness of such resources is maximized. Besides the cost effectiveness of sharing Internet access, there may be other benefits of developing a community network. Here are a few listed below.

Shared Expertise. As mentioned earlier, when two or more entities build a cooperative network, it may be possible to hire full-time technical support personnel. For many organizations, this is not feasible to do alone. There are many factors to consider besides the cost of personnel, but having access to adequate system support is very beneficial.

Shared Training. When two or more entities cooperate, it is possible to share the cost and benefits of staff training. For example, it may cost less to bring a trainer onsite to perform training for key staff of both entities than to pay a per- seat training charge when sending individual staff to train- When two or more ing sessions. Also, it is possible to share the knowledge staff receive at outside training sessions with members from entities build a coop- other organizations. Such cooperation maximizes the benefit of training funds. (And, yes, there may be problems to be erative network, it worked through. But isn’t this a good problem to have, rather than to have no option at all?) may be possible to hire full-time Centralized Administration. When developing a computer network involving multiple entities, one entity usually acts technical support as the administrative agent for the entire network. While there will be meetings involving administrators from all personnel. entities, and while there will be work for members of all entities, one entity usually deals with procurement, installation, and maintenance issues with the various vendors. This prevents duplication of work, which is common when each entity must perform these duties to administer separate Internet connections.

Other Benefits. Along with the previous items, here are a few other possibilities that may present themselves when multiple entities share network connectivity:

¨ A foundation for future cooperation will be established. ¨ The partnership may foster better communication among leaders in the cooperating organizations.

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¨ The network will allow the sharing of information resources (automated library systems, information databases), subject to appropriate licensing). ¨ Information regarding outstanding fines (e.g., for overdue library materials) can be shared to assist the entities in recovering materials, fines, etc. ¨ A foundation for future grant funding will have been laid.

Disadvantages of a Community Network

While there are numerous benefits to community networks, it would be unfair to lead you to believe that everything about community networks is good. There are a few disadvantages as well. Many of these are the same regardless of the type of collaborative effort involved. Let’s use a big-city car pool as an example. There are four primary benefits:

¨ saving on gas and car maintenance bills ¨ providing more human interaction during a commute ¨ reducing air pollution ¨ lessening of congestion on crowded roads

How can something that accomplishes those objectives be bad? Well, it depends on personalities. Here are some of the negatives of big-city car pools:

¨ decisions must be cooperative to maintain harmony in the group ¨ one’s schedule is dependent on the group, so individual errands are difficult or impossible to accomplish ¨ it usually takes longer to get to work and back

Here are the principles repackaged for community networks.

Administrative Harmony. When developing a cooperative network, cooperation and compromise are the important principles which allow the various participants to get most of their needs met. Some goals may have to wait for future development. Some desirable services may interfere with others’ use of the system. Communication procedures must be put in place to keep everyone informed and “in the loop.”

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Some concessions may need to be made to one entity to interlocal agreement—a legal keep the group together. document describing an agreement between two or more Calendar Constraints. When an organization develops a local governmental agencies to project on its own, there are no other members to consider work as one agency on a project. The agreement generally lists the when it’s time to begin implementation. When the organiza- rights and responsibilities of each tion is ready, the process begins. But when other entities participant. are involved, an adequate period of time may be required to allow everyone to get ready. Some organizations will feel constrained by this “group calendar.”

Longer Process. Like the beginning of the process, the end may be affected as well. It may take longer to get the project implemented for some entities than others. For the early finishers, there may be a period of waiting until the others finish. So the process may take longer for some than if they had worked alone.

But all of these negatives can be addressed. Generally, by developing a formal interlocal agreement, the agencies involved can address these concerns and list the responsibilities each will assume in accomplishing the project. Rewards and penalties for early or late completion of the project requirements may also be included. In this way, an interlocal agreement—combined with a timely, inclusive communication process—will remedy many of these negative aspects of a cooperative venture.

Summary

In this chapter we have presented a general overview of creating common network infrastructure to share network services. Specifically, we have pointed out many advantages and a few disadvantages of community networks.

Potential Benefits:

¨ Cost effectiveness ¨ Better bandwidth utilization, or increased bandwidth ¨ More reliable Internet connectivity ¨ Shared technical expertise ¨ Shared training ¨ Centralized administration ¨ Establishes foundation for sharing new services ¨ Provides a means of efficient communication among participants

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Needs for Successful Collaboration:

¨ Formal interlocal agreement ¨ Coordination and communication with other agencies ¨ Longer implementation period

20 Library Development Division CHAPTER TWO Where Wireless Connectivity Fits In

As one begins to look at sharing any type of network resource—especially the Internet—in a remote, rural public library, ongoing cost will be a major determinant in the sustainability of the project. Therefore, wireless network connectivity is an attractive alternative to cabled, also called wireline, connectivity. With the pressure public agencies feel to maximize the usefulness of taxpayer dollars, wireless networking is even more attractive.

In this chapter we will explore the basic questions sur- rounding use of wireless connectivity to create or extend a community network. What is wireless networking? When is it appropriate to implement? What is required to implement it? How does it compare to other alternatives? To get a better feel for radio waves and how they are used for data communications, I’ve included a simplified discussion in Part II. For more information, see Chapter 8, “How RF Wireless Connections Work.”

What is Wireless?

So far we have spoken of computer networks as a group of computers connected by physical cabling, either network cabling inside a building or telephone lines or data circuits outside a building. Traditionally, such connectivity has used copper wires to carry the electrical signals. Over the past two decades, fiber optic cable has become commonly used and is now included in this class of “wired” connectivity.

Over the past few years, a new way to create network connections has emerged which does not use wires. It is called wireless connectivity. Wireless connections all use some

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Airwaves form of radio waves, called microwaves at the higher end, to carry data from a transmitter to a receiver. Radio signals are commonly thought to travel through the Four different categories of wireless communications are earth’s atmosphere, what we call generally used for network connectivity: radio, microwave, “air.” But they don’t require air. infrared, and satellite. Satellite is different from microwave They travel through free space. only because its transmitter/receiver is not earth-bound. Radio signals are technically (Satellites use microwave frequencies to carry their signals.) waves of electromagnetic These are all described further in “What are Wireless radiation, just like visible light Technologies?” on page 89. and x-rays. Only their waves are much, much longer. They not only travel through the air, but All wireless technologies use standard computer networking also through space, just as light technology saddled over a wireless medium: airwaves. does from the sun to earth. Because signals are transmitted across space, there is no cable between network access points, and, therefore, no Broadcasters in the early radio monthly line charges for leasing a physical wire. This is industry coined the term “on the air” and “airwaves” and the wireless connectivity’s major advantage. terms stuck. So now we typically say that the medium used in For one form of wireless communications, however, there is wireless communications is “the an additional benefit. Radio frequencies are available which airwaves.” do not require a license.

Licensing

The United States Federal Communications Commission (FCC) regulates the use of airwaves across the country to prevent conflicts arising when two entities try to communicate using the same frequencies. The effect of licensing is most commonly seen in radio and television broadcasts. But licensing also applies to other types of radio communications, such as police and fire department communications.

In fact, in order to communicate over almost any of the radio spectrum, a license is required from the FCC. In the licensing process, the FCC assigns a narrow band—a range—of radio frequencies for an applicant’s use. The license grants the applicant an exclusive right to use the assigned frequency in a specific geographic region. No other entity operating in the same region can legally use the licensed frequency.

The benefit of the narrowband license is the absence of interference. Legal recourse is possible if an outside agency begins to use the assigned band. On the other hand, the application process may take several months to complete.

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The FCC has reserved three large bands of radio frequencies (called the ISM bands) for general use by the industrial, scientific, and medical communities. These bands are non- licensed bands, meaning any agency can use them without having to obtain a license from the FCC. Law requires devices operating at these frequencies to be low-powered, minimizing the possibility or effect of interference. Examples of devices using these frequencies include baby monitors, garage door openers, and others.

With unlicensed frequencies available, many wireless devo- tees have begun to use radio frequency wireless technology to serve as a carrier for network data signals. Let’s take a moment and examine radio frequency next.

Radio Frequency Communications The Industrial, Radio frequency (RF) communications technology is based Scientific, and on the same technology that radio and television broad- casting uses. One of RF wireless’ benefits is that it uses Medical (ISM) bands unlicensed frequencies, the ISM bands. However, this also means that many users might potentially try to use the are non-licensed same frequencies. In these cases, it is up to the various entities involved to work together to avoid interfering with bands, meaning any each other’s communications. agency can use them While this might be seen as a major detriment to RF communications, private and military investigation into the use without having to of RF technology over the past four decades has provided a solution for minimizing or eliminating interference and for obtain a license from providing security over a radio link. For a complete discussion of the solution for such conflicting frequency use, see the FCC. the section “Spread Spectrum Technology” on page 95.

For most small communities considering wireless network connectivity, RF wireless provides the most cost-effective, secure means of communication. In the remainder of this manual, we shall be speaking solely of RF wireless when we use the term wireless.

Let’s take a look at its benefits and disadvantages and see when it is the most appropriate type of connectivity.

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right-of-way fees—fees incurred Appropriateness by crossing public or private land in the process of burying cable or By using the word appropriateness, we have already as- pipeline or installing cable on utility poles. These usually take sumed that wireless networking is not the best alternative the form of monthly or annual in every situation or for every segment of the community payments to the rights holder. network. There are some distinct characteristics which make wireless optimal for some connections.

Low Cost. The major benefit of wireless data connectivity is its extremely low initial and ongoing cost. Because no physical lines or circuits are involved, there are no ongoing monthly expenses for leasing a line. The only ongoing cost incurred is maintenance of existing equipment, which is similar regardless of the type of connection used. This absence of monthly lease fees can result in large savings in telecommunications costs.

However, private fiber optic connectivity may also provide zero monthly fees—if no right-of-way fees are incurred. In such cases, if the cost of fiber installation is close to the cost of wireless connectivity, or less, a fiber optic connection represents the more effective option.

Bandwidth. One of the primary concerns when creating a computer network is speed, or transfer rate. How much data can be sent across the connection in a specific period of time? The more data that can be transferred, the better the connection is for end users. The terms most commonly used to describe the transfer speed of a connection are bandwidth, throughput, line speed, and data transfer rate. They tend to be used interchangeably. If you are fairly new T-1 Line—a special type of tele- to computers, you may wish to read Chapter 5, “Data phone line called a data circuit. Transfer Rates: A Primer.” It covers all of the concepts and T-1 lines connect two distinct words you’re likely to run into when talking about the points to allow intercommunica- speeds of network connectivity. Likewise, all the various tion. They are not “dialable,” or switchable. They can carry both methods of connecting buildings across town (or across the voice and data signals. country) into a wide area network (WAN) are discussed in Chapter 7, “WANs, MANs, and the Internet.” Take a look if ISDN Line—another special you need to learn more about T-1 lines, ISDN lines, and how phone line, carrying only digital the speeds of these compare. (discrete) signals. ISDN lines are switchable and can be used as regular phone lines. Now they General wireless networking equipment provides data are primarily used to carry data throughput of about 1Mbps. Since this is about two-thirds traffic. Two types are available: the speed of a T-1 line, and about eight times the speed of BRI (basic rate interface) and an ISDN line (BRI), wireless provides a viable high-speed PRI (primary rate interface); the option to leased lines. This provides a high-end solution for PRI line is equivalent to 23 BRI lines. sharing Internet connectivity.

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However, other network services may be beneficial over a Ethernet—a standard computer community network. Examples include sharing file servers, networking communication applications, CD-ROM information databases, local organi- format. It is the most common zation information, and others. In these cases, the 1Mbps network format in use today. Another that is still in wide use in throughput of wireless may prove to be too slow. (Over businesses is Token Ring. normal Ethernet networks, the current available bandwidth is about 10Mbps.) High-speed wireless, sometimes called wireless Ethernet, can help. Data throughput of 5-7Mbps can be gained over short distances via bridges using higher frequencies. With the recent introduction of 11-12Mbps bridges for local area networks (LANs), one can expect the actual throughput of WAN bridges to increase as well. The cost of these high-end bridges is about four to five times the cost of base-level wireless bridges.

So, where high throughput is necessary, wireless connectivity may not be as appropriate a solution as private fiber Benefits of Wireless: optic cable. Especially where the base cost for both is similar. (However, under current requirements, the Texas - Low ongoing costs Telecommunication Infrastructure Fund [TIF] grants will not pay for external cabling. TIF will pay the cost of inside - Easy implementa- network equipment, including wireless bridges—but only as much as the cost of the equivalent equipment required for tion T-1 connectivity.) As you can see, appropriateness can only be determined after a careful analysis of the potential - Effective data benefits of each method of connection. transfer rate Line of Sight Considerations. One other significant factor affecting the appropriateness of wireless connectivity is the - Mobility line-of-sight requirement. This topic will be briefly revisited in the next chapter on page 34 as part of a discussion on - Redundancy site surveys. For now, let it suffice that if desired remote connection points can be seen from the central site—either with the naked eye or through a telescope—wireless transmission is possible. Even if not, measures can be taken to establish line of sight. The major factor is cost. If line of sight cannot be gained easily, the wireless link may not be feasible.

Benefits

Low Ongoing Costs. Wireless technology offers several advantages. Foremost is its low ongoing costs. Table 2 on the next page shows a comparison of costs, including the ongoing costs, of four methods of establishing a high-speed network link—one with at least 1Mbps throughput.

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Table 2. High-Speed Network Connectivity Comparison Low-End High-End Private Description T-1 Line Wireless Wireless Fiber 150- Throughput 1.5Mbps 1-1.6Mbps 5-7Mbps 300Mbps Monthly Cost $250-750 $0 $0 $01 Installation, per $2,500- $1,000- $500-1,500 $500-1,500 site 3,5002 2,5003 $2,500- $650-$4,000 $650-$4,000 External Wiring $0 6,000 per per site4 per site4 qtr. mile Router, Equipment CSU/DSU Wireless Wireless Bridge, or Required, per site Router Bridge Bridge Switch Equipment Cost, $1,500- $1,750- $9,500- $1,500- per site $3,500 $3,000 $10,500 $2,500 Distance Limit5 None 6-15 miles 3-6 miles 2-8 miles Notes: When fiber optic 1 There is no monthly cost for the fiber link itself, but right-of-way fees may have to be paid; such fees can be negligible or very expensive. connectivity proves to 2 Installation costs for T-1 lines vary greatly depending on the local telephone company, but are generally about $700-$1,000. In Texas, both be too expensive to Southwestern Bell and GTE waive the installation cost of the original T-1 circuit as part of their legislatively reduced data circuit costs (HB2128). This cost also includes installation of the CSU/DSU and router. install initially, 3 Fiber optic installation costs are highly dependent on distance and type of installation (hung on utility poles or buried). wireless provides 4 Wireless connections require at minimum an external antenna, lightning arrestor, and cabling to the bridge. In some installations, a radio mast or very good base-level tower will also be required. 5 Maximum distance network signals can be carried reliably without connectivity. regeneration. For wireless connections, this is dependent on antenna installation. For fiber optic cable, this is dependent on cable type: multimode or single-mode.

Ongoing costs shown in the table are charges just for the use of the transmission medium (zero for wireless). One must also budget for anticipated maintenance costs. For example, equipment configuration updates might be needed, or electrical problems might cause loss of configuration. For routers and bridges, the cost of such maintenance will be similar for each connectivity type. However, if a fiber-based switch is used, one can expect to need less maintenance. On the other hand, high winds or other factors may cause misalignment of or damage to the antennas required for wireless connectivity. Budget more for wireless maintenance and less for fiber connections employing fiber-based switches.

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Ease of Implementation. A second benefit of unlicensed RF wireless connectivity is speed of implementation. When procuring a T-1 circuit, an organization must wait for delivery and installation by the local phone company. Wireless connectivity can be installed as quickly as the procuring agency can complete the paperwork with the wireless vendor and schedule an installation. One school and public library had a working wireless link about a week after approval had been granted.

Effective Base-Level Data Transfer Rate. When fiber optic connectivity proves to be too expensive to install initially, wireless provides very good base-level connectivity. Wireless allows an organization to begin networking at about T-1 speeds and update that throughput as funding becomes When the wireless available. connection is up- Mobility. One benefit of wireless will be apparent only when an organization needs to move an office. When wired con- graded to fiber optic nectivity is used, it can be extremely expensive to move an external network connection. In the case of private fiber it cabling, leaving the may be necessary to install a completely new fiber segment. In the case of leased T-1 circuits it means paying for instal- wireless link in place lation charges at the new site. Plus, the organization once again must wait for new installation before connectivity can as an active secon- be resumed. In wireless connections, the antenna can be taken down and the equipment moved to the next site. Only dary link will provide the cost of setting up and realigning the antenna will be incurred. base-level connec-

Redundancy (in Future Growth). In many cases, a wireless tivity if the fiber link network can be established as an interim technology. As more and more cabling infrastructure is required in the ever fails. future, it may become either necessary or more cost effective to install private fiber optic cabling as the backbone of the community network. This will certainly become more of an issue when motion video is in common use over corporate networks.

When the wireless connection is upgraded to fiber optic cabling, the wireless connection still has a role to play. By leaving the wireless link in place as an active secondary link, it will provide base level connectivity if the fiber link ever fails. Emergency traffic can still be routed. Using a wireless link while it is cost effective today will provide an efficient backup link tomorrow in the event of technical problems.

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Disadvantages

When considering options for wide area networks, it is appropriate to consider the few disadvantages presented by wireless technology. These have been mentioned in the previous section on appropriateness, but they are discussed more fully below.

Radio Interference. When multiple radio antennas are located in close proximity, or many strong spread spectrum sources inhabit a small geographic region, RF wireless loses some of its effectiveness. The signals may interfere with each other, causing re-transmission of signals and loss of throughput. But such sources are unusual in many rural communities.

Path Interference. Radio wireless technology is commonly Disadvantages of advertised as “impervious” to weather. This means, essentially, that particles of rain, fog, smog, and dust are Wireless: not large enough to block the transmission of the radio signal. In the 902-928Mhz frequency spectrum this is - Radio interference essentially true.

- Path interference However, it is not always true in the higher frequency ranges (2.4Ghz and 5.7Ghz) used for higher-speed wireless - Physical damage connections. In these, the wavelengths are short enough that such weather-related phenomena may interfere with - Low throughput some transmissions. Re-transmission of data will be necessary, lowering overall performance. Nevertheless, the actual compared to fiber performance during such conditions may still be greater than the maximum performance of a T-1 circuit.

Weather and Accidental Damage. Because wireless connectivity uses external antennas, severe weather may damage these components. Lightning arrestors will be used to prevent damage to internal network equipment, but very high winds may still misalign or damage antennas. Also, one must allow for the possibility of accidents in which antennas are damaged. But these same types of damage may occur to privately owned fiber optic circuits (fiber hung on electrical poles may be broken or damaged in severe weather, while trenched fiber cables may be accidentally cut by other utility contractors).

Leased circuits are also susceptible to weather damage and accidental damage. The difference in these cases is that the cost of repairing privately maintained connections is born

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by their owners. Adequate budgeting and contingency throughput—commonly used as planning must be part of establishing a private connection. a synonym for data transfer rate or bandwidth. In wireless appli- Throughput. While wireless connectivity offers a better cations, it refers to the actual quantity of data that can be cost/performance ratio over time than leased data circuits, transmitted over a wireless link. fiber optic connectivity offers an even better solution. It has much greater potential for throughput. In many cases, it is the best choice.

On the other hand, if the only resource that will be shared among community entities is Internet access, WAN link throughput above 2Mbps is of little concern. The shared link to the Internet will be the network bottleneck. It normally will be constrained to one or two T-1 channels of access (1.5 to 3Mbps). In these cases, fiber connectivity will Questions to Consider: be overkill except as a foundation to future joint projects. - Uses for the Basic Considerations for Implementing network Community Networks - Services to be As pointed out in the previous section, making a decision on how to implement community network infrastructure is shared not necessarily simple. There are many factors involved. In order to be sure that radio frequency wireless is the best - Number of simul- choice in a particular situation, one must consider each of these. The following steps form a plan to help you taneous users determine if wireless is the best option in your community. - Number of users Need Assessment. For what purpose will the community connecting at peak network be used? What applications/services will be shared? On average, how many users will be using network times services from an external entity at any one moment? How many users will be connecting over the community network at peak times? Determining answers to these questions will assist a network planner in determining average and maximum loads on any particular segment of the network.

One critical question involves streaming video. Will the network be used to transmit full motion video in real time (for example, as part of a videoconferencing application)? If streaming video—full-motion so, there are two important considerations in the network video, such as that seen in design: throughput and latency. Motion video involves very movies or on TV, delivered large data transmissions. And it also requires very short across a computer network; the computer user sees the video delays (called latency) in the packaging, transmission, playing onscreen as it is acknowledgement, and display process. Unless two delivered, rather than after the separate links are used for each connection, so that complete file as been received.

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transmission and reception can occur simultaneously, wireless links involve relatively long latency. In these cases, wireless may not provide a feasible solution.

Leased Circuit vs. Private Fiber vs. Wireless. Each of these types of connectivity is appropriate in the right circumstance. In the wrong circumstance, each can also be very inappropriate. Here are some guidelines to help you determine which is most appropriate for your use:

¨ In many cases, a mixture of these linking technologies may be the best solution. ¨ Fiber optic links provide the highest throughput. ¨ Wireless networking is the only option for mobile communications. ¨ Wireless networking also offers the easiest and least expensive means of moving an access point. ¨ Leased data circuits provide the most hands-off connectivity; if there is a problem with the link, a phone company technician will troubleshoot it. ¨ In contrast, if a fiber optic cable or a wireless antenna is damaged, the circuit is down until the organization has it repaired. ¨ Low-end wireless and T-1 leased circuits provide about the same level of throughput.

Summary

In this chapter we discussed what wireless connectivity is. We also presented information about its appropriateness, its benefits, and its disadvantages.

Wireless networking can include these forms of wireless communications:

¨ Microwave ¨ Satellite ¨ Infrared ¨ Radio Frequency

This manual primarily discusses radio frequency wireless applications.

Next, we mentioned the three factors that most affect the appropriateness of wireless as a networking medium:

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¨ Ongoing cost ¨ Bandwidth ¨ Line of sight considerations

We also listed five benefits of wireless networking:

¨ Low ongoing costs ¨ Ease of implementation ¨ Effective base-level bandwidth ¨ Mobility ¨ Redundancy (in future growth)

And we presented four disadvantages of wireless connectivity:

¨ Frequency interference ¨ Path Interference (objects and even weather) ¨ Weather and accidental damage ¨ Lower bandwidth (in comparison to fiber optic cable)

Last, we discussed basic considerations in implementing community networks:

¨ Conduct an appropriate needs assessment ¨ Discuss bandwidth requirements ¨ Review the merits of all options for connectivity— leased lines, private fiber, and wireless

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CHAPTER THREE Budgeting for Wireless Connectivity

Once you’ve become interested in radio frequency wireless as a potential solution for your network needs, the big question is “How much will it cost?” In this chapter we focus on the cost of implementing wireless connectivity. The cost components can be broken down into four basic areas: preparation, equipment, installation, and maintenance. Cost components can

Preparation be broken down into four basic areas: All organizations looking at connecting to other computer networks must first consider the potential pitfalls that may - preparation occur during the initial phase of creating a WAN. Regard- less of the type of connection ultimately used, a preliminary - equipment investigation can point out some of these pitfalls. For wireless connectivity, the preliminary investigation is called - installation a site survey. - maintenance A complete site survey investigates these areas of implementation:

¨ Radio frequency interference ¨ Line of sight ¨ Antenna and tower requirements ¨ Structural problems

Interference. Because of the nature of spread spectrum radio transmission used in wireless network products, interference is normally not a problem, especially in rural areas. (Turn to “Spread Spectrum Technology” on page 95 to read the details.) However, more than one organization has found during the installation of equipment that powerful, fairly wideband radio transmissions are present in the local area that prevent the proper operation of their equipment.

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What are the sources of existing radio frequency installations that might interfere with a new one? Many times, police, fire, and emergency response facilities use the same radio frequencies in creating mobile communications systems. Military facilities also may have wireless communications in place. A nearby factory or warehouse might be using an internal wireless network or communications system operating in the same frequency range as the proposed community network. Even internal microwave ovens have been known to cause some interference, reducing the performance of a wireless connection.

Any existing radio frequency usage can be discovered through a process known as spectrum analysis. This frequency examination is generally conducted at each site Radio frequencies in the wireless network by a certified radio technician using a spectrum analyzer. Since these devices are expensive to used in community the installer, including a spectrum analysis as part of one’s site survey will add significantly to its cost. (A list of wireless networking charges generally incurred in having a site survey performed is listed in Table 3 on page 36.) do not pass through Line of Sight. Unlike radio and television broadcasts, and solid objects like even cellular phone transmissions, the radio frequencies used in community wireless networking do not pass buildings or trees. through solid objects like buildings. And these signals can be degraded or blocked when passing through trees. Because of this, we Because of this, we say that wireless networking requires say that wireless clear line of sight. networking requires Generally, if it is possible to see clearly from the rooftop of one building to the rooftop of the other building involved in clear line of sight. the wireless connection, then line of sight can easily be established. There are a few tricks regarding this “seeing,” though. First, see means visible to the naked eye or with the aid of a telescope. Second, see clearly means visible without having to peek through tree limbs. Certainly, this does not include seeing the destination point occasionally through tree limbs swaying in the breeze! Last, seeing is used in a radio sense, not a visual sense. Technicians use a more precise term: radio line of sight.

Radio line of sight is a little “broader” than visual line of sight. Due to the way radio signals are transmitted and received, the clearance around the mid-point of the line between two sites must be larger than at the end points. Think of taking a long string and stretching it between the

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two points so that just a little slack is present. If the line were twirled around like a jump rope, the cylinder created in space would be thicker in the middle than at the ends. Radio transmission creates a path like that, but much thinner. Objects, including trees, which intrude into that imaginary cylinder can cause reflected signals, degrading or canceling some portion of the radio signal.

A site survey includes the determination of clear line of sight for all sites involved in the wireless network. If line of sight is not technically available, the technician performing the site survey will determine what other options might provide clear line of sight. Depending on funding, there may be multiple options.

The line of sight must exist between the two antennas involved in a wireless link. In some cases, locating antennas If line of sight cannot on one side of a building or another will provide adequate line of sight. In other cases, raising the antenna with a ten- be established fea- foot or twenty-foot mast mounted to the roof of a building sibly between two will provide adequate clearance. However, this option requires securing the antenna with guy wires. The actual sites, antennas/ structural condition of the building may accommodate or inhibit such mounting. towers and wireless In cases where a twenty-foot mast does not provide suffici- units can be erected ent height to obtain clearance, radio towers can be erected. Typically, these are erected at ground level beside the at a third site to building—although some building structures will permit a roof-based tower. Ground-based towers are typically at create a repeater least forty to fifty feet tall. If a twenty-foot mast cannot be erected on a rooftop for any reason, a thirty-foot ground- link. based tower provides roughly the same level of clearance. If necessary, and depending on an agency’s budget, much taller towers can be erected.

A final option is the use of a repeater link. If line of sight cannot be established feasibly between two sites, separate antennas/towers and wireless units can be erected at a third site. This site must have clear line of sight to the two original sites. In this scenario, the alternative wireless unit receives a signal from one of the original sites and re- transmits it, or repeats it, to the other site.

Distance Considerations. In addition to line of sight considerations, the site survey will determine the approximate distances between end-points of all wireless links in the

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network. The distances involved will determine the types of antennas that may be used, and if amplifiers are required. For network links that span distances of more than a mile or two, a topographical study may be required to determine if any topographical barriers exist. As a note, successful wireless links of fifteen to twenty miles are documented on the web.

Physical Structure Analysis. The final aspect of the site survey involves the physical structures at each location. The following questions are usually addressed:

¨ Can antennas or antenna masts be attached to the building, or will there be problems? ¨ What problems might arise in drilling through the building to run the cable from the antenna to the wireless bridge? ¨ Where will the wireless bridge be located? ¨ What length of cable is required for each site? ¨ How will the cable be installed to avoid any internal The key component of hazards? a wireless network Costs. A site survey may take as long as a full day for a single link (two sites) or two-to-four days for larger net- link is a device called works. As mentioned before, the spectrum analysis adds significantly to the cost. Table 3 lists approximate costs for a wireless bridge. a standard site survey. To determine more specific site survey costs for a project you may be interested in, contact sales representatives from at least two or three of the wireless vendors listed in Appendix B.

Table 3. Cost of Wireless Site Survey.

Description Cost per Day Basic Site Survey, including line of sight determination, distance calculations, physical structure study $250-$500 Radio Spectrum Analysis $400-$7001 Engineering Study (Topographic, generally done off-site) $100-$2002 Travel Expenses (highly variable), depends on the distance traveled, local costs, and the number of technicians required $250-$400 Notes: 1 When spectrum analysis is performed as part of the site survey, the total site survey cost will normally be less than listed. Expect $750-$1,000 per day. 2 This service may not be available from all vendors. Where available, the cost is fixed. Some vendors credit the cost of the RF engineering study if installation is purchased through an authorized reseller.

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Equipment

As opposed to site survey needs costs, the cost of wireless equipment is straightforward. Questions regarding equipment are mainly related to the throughput desired, the strengths of the features provided, and whether a mast or radio tower is required to elevate the antenna.

Wireless Bridges

The key component of a wireless network link is a device called a wireless bridge. A combination of a network bridge and a radio transceiver, the bridge is a component on the local network. It examines all data traffic. It sends any data bound for the network on the other side of the wireless link to the radio transceiver. The transceiver then alters the signal and sends it to the antenna, where it is transmitted to the antenna on the other side of the link. One can say it acts as a traffic cop for network data. (Detailed explanations of wide area networks and wireless networking are provided Ideally, the bridge in Chapters 7 and 8 for those who want to learn more.) should serve your While the function of all wireless bridges is the same— getting data from one network across the airwaves to projected needs over another network—not all wireless bridges are the same. The feature sets are slightly different. In reviewing the various the next four to five vendors’ products, it’s easy to see that some serve the low- cost market, where price is the ultimate bottom line. For years. others, security is supreme. For still others, the performance in transferring data is the most important factor. Some vendors have worked especially hard at making the bridge easy to configure and maintain.

Because each implementation is different (depending on network needs, buildings, environments, levels of technical expertise), it is difficult to say which product is right for your situation. However, the first consideration should be throughput. Which product will provide enough throughput for you to accomplish your goals for the network?

Think about how much throughput is appropriate for your implementation. And don’t think just about immediate use. How you will use the link over the next few years must also be considered. Ideally, the bridge should serve your projected needs over the next four to five years, or you should have a plan to enhance its throughput in that time period if future growth requires it. For example, if a 10Mbps bridge

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is too expensive, but you are reasonably certain your Desirable Features network use will grow so that you need more bandwidth, you can implement a 2Mbps solution now and add a second Here is a list of security and 2Mbps link in two to three years. Some products make this configuration features you may solution easy. wish to look for in a wireless bridge: When is a 10Mbps bridge necessary? If you will be heavily ¨ SNMP management with full sharing CD-ROM databases, or any applications, over the MIB II compliance (Manage- network, or if you will have a large number of users occa- ment Information Base II) sionally use such shared resources, a 10Mbps bridge will ¨ Modifiable SNMP community be important. Conversely, if the link is being established name ¨ Access control lists only to share web-based resources, with occasional access ¨ If desired, DES (Data to centralized databases, a 10Mbps bridge will probably Encryption Standard) never function to its fullest extent. encryption for link encryption But there are other factors to consider as well. Here are ¨ Windows 95/NT configuration software some fairly common activities you might incorporate into ¨ Capability to configure the your evaluation process: bridge or update its software across the wireless link ¨ Contact at least three vendors listed in Appendix B and request product literature. Review the materials to see which company has made the best effort to help prospective customers understand the technology. ¨ Request a review copy of the documentation for the equipment you may be purchasing. Which companies do the best job of producing documentation that helps you understand how to operate your equipment? ¨ Examine reviews of wireless bridges. Which products are rated best in the areas most important to you? ¨ Examine the terms of each vendor’s warranty and their product support program. ¨ Contact each vendor’s technical support department one or two times and submit questions. Whose is the most helpful? (Remember that you may never deal directly with the sales person again after your product purchase. Any operational questions will probably be referred directly to technical support.) ¨ If the security of the wireless link is a concern, see which wireless products support encryption. Another security issue relates to remote management of the bridge. Some bridges can be administered from any workstation on either side of the link. How does the product protect against unauthorized access to the bridge management functions? ¨ Check references. Don’t hesitate to call other users or the Better Business Bureau regarding a vendor or one of its resellers.

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The pricing of wireless bridges varies considerably from one vendor to another. At the low end of the pricing spectrum, expect to pay about $1,800 for a 2Mbps RF bridge. At the upper end, expect to pay $2,750 to $3,000 for a 2Mbps bridge. However, 10Mbps RF bridges are slightly more stable in cost, generally around $10,000.

Antennas

Antennas actually emanate the signal from the radio transceiver in transmit mode and receive the signal at the other end of the connection. There are basically two different types of antennas for wireless networking: directional and omni-directional. A point-to-point A single-link, point-to-point, connection uses two directional antennas pointed at one another. Wireless connections with connection uses two a central site and two or more remote sites being linked are called multi-point connections. Multi-point connections directional antennas generally use an omni-directional antenna at the central site. Because it transmits in all directions, all the remote pointed at one sites can pick up its signal. Each remote site has a directional antenna aimed back at the central site antenna. another. Multi-point connections, with a Because the energy of an omni-directional antenna must go in all directions, it diminishes quickly. Therefore, omni- central site and two directional antennas can’t transmit as far as directional antennas. When the distance between the central site and or more remote sites, the remote sites is greater than two or three miles, you may need to use multiple directional antennas rather than an use an omni-direc- omni-directional antenna. tional antenna at the However, even directional antennas have varying properties, enabling some to transmit farther than others. During the central site. site survey, technicians will determine which antennas will work best in your situation. For our purposes in this chapter, the key issue is cost. A sample of various antennas, and the approximate costs, are shown in Table 4 on the next page. For more information about antennas and how they work, see “How the Antennas Work” on page 99.

Masts and Towers

The more costly aspect of antenna installation is the mast or tower required to achieve line of sight. In rare cases, usually over short distances, line of sight can be established with the antennas mounted directly to the rooftop of

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gain—a measure of the ability of Table 4. Common RF Antennas. a radio antenna to “pick out” specific radio signals; a value specifying the "focus" of a radio Type Gain Cost antenna in transmitting/receiving Directional, Grill 24dBi $325-$375 a radio signal. Directional, Panel 13dBi $250-$275 Directional, Yagi 14.5dBi $200-$300 Omni-Directional 6dBi $200-$250 Omni-Directional, Horizontal or 8dBi $550-$800 Vertical Polarization

both buildings. But, usually, some form of mast is required to raise the antenna to a sufficient height to achieve line of sight. In more difficult cases, radio towers may be necessary or may be more prudent. These issues should be resolved during the site survey.

Table 5 shows the approximate cost of common masts and The more costly radio towers. These costs include the parts and labor required to assemble and erect the structures and mount the aspect of antennas antenna. Labor costs for aligning the antenna, done at the same time, are covered in the installation section. are the masts and towers required to Table 5. Radio Masts and Towers, Approximate Costs. achieve line of sight. Type Cost 20ft Mast $1,100-$1,400 30ft Tower $2,000-$2,250 40ft Tower $2,500-$2,900 50ft Tower $3,400-$4,000

Accessories

There are several other components included in a radio wireless connection. A lightning arrestor is connected between the antenna and the wireless bridge to prevent damage to the unit that might be caused by a lightning strike. Also, an emissions filter might be used to reduce extraneous noise. Finally, where masts or radio towers are required, you may need extension cables to connect the antenna to the bridge. Extension cables will also be required when the wireless bridge is located inside the building far away from the point where the primary cable enters the building.

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Installation

Installation is the last cost component in implementing wireless network links. While it is technically possible for a layperson to install all of the components, hiring a certified installer is highly recommended. Some might call it a requirement. Here are three reasons why paying the vendor to do the installation is a good idea:

¨ Experienced installers generally provide a better alignment of the antennas at each connection site, providing the best throughput possible over the wireless link ¨ Trained installers will be able to install the network bridge and make sure it is properly configured and operational ¨ If a professional installer is used, any configuration problems can immediately be referred back to the While it is technically installer for resolution possible for a Installation generally includes these services: layperson to install ¨ building/erecting the masts or antennas ¨ mounting the antenna all of the components, ¨ drilling through the building and running a cable from the antenna to the wireless bridge hiring a certified ¨ setting up and configuring the wireless bridge ¨ aligning the antenna and testing the connection installer is highly

Installation is performed at each site in the wireless net- recommended. work. In most cases, the cost will range from $600-$1,000 per site. For a multi-point connection, the cost of installation at the central site may be higher because more work will be required to maximize the signal quality of connections with all outlying sites. A variety of factors can affect how smoothly the installation goes, however, so budgeting slightly more funds as a contingency is not a bad idea.

Maintenance/Ongoing Costs

Organizations generally pay annual maintenance fees for “mission critical” equipment such as routers and bridges. Unlike single computers, if a router or a bridge goes down, many people’s work is impaired. Paying maintenance fees usually provides the organization with next-day replacement of malfunctioning equipment. Most vendors charge

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about 10% of the original purchase price of the equipment for maintenance.

However, in situations where four or more wireless bridges are purchased, it may be more cost-effective, and more timely, to purchase an extra unit. The initial cost of the extra unit will be recovered over the course of two-and-a- half years or less by not having to pay the maintenance costs. Having an extra unit immediately available should an active unit fail greatly reduces the duration of downtime.

Since there are no recurring monthly fees for connectivity, one might think the ongoing costs story is over. Unfortu- nately, there are always “hidden” costs. As I mentioned Where four or more earlier, wireless connectivity is susceptible to weather- related and accidental damage. If an antenna is damaged wireless bridges are for any reason, the wireless link will be inoperable until the antenna is repaired or replaced. Therefore, it is important to purchased, it may be plan for such disasters as one does with other computer- related technology. Having a small repair/replacement more cost-effective to allocation in the agency’s budget will do a great deal to minimize the impact of such damage. purchase an extra unit. Having an extra Community Network Configuration and unit immediately Budget Scenarios available greatly re- In order to illustrate some of the common ways wireless networks might be implemented in small communities, we duces the duration of will go over three separate examples, or scenarios. For each scenario there is a short description of the significant downtime. details involved in creating the network, a diagram depict- ing the network, and a detailed budget of the initial costs of equipment and any ongoing costs involved. There is also a comparison of the costs in establishing the same network using dedicated data circuits—T-1 lines.

The first scenario shows a network being created between a public library and the local public school district. In many communities, a de facto relationship already exists between these two entities, so it’s a natural place to start. The public library provides research materials and some curriculum support for student research projects. In some cases the public library also provides support with such projects as the Accelerated Reader program.

42 Library Development Division Budgeting for Wireless Connectivity

Creating a communications link between the two provides several benefits:

¨ a direct means of sharing information in each entity’s library catalog ¨ a means of sharing other electronically-based information resources, such as periodical databases (as licensing allows) ¨ a means of maximizing the effectiveness of taxpayer dollars in providing access to the Internet

Scenario #1. Simple Point-to-Point Link.

In this example, a single wireless link is created between the public library and the school district’s high school. The two entities will share the district’s Internet access.

The high school has a leased T-1 line connected to an In some cases the Internet service provider. In this simplest of scenarios, no provision is made for network security through the use of expected risk of firewalls. In some cases the expected risk of outside attack is extremely low, so the addition of firewalls is seen as an outside attack is unnecessary expense. (We recommend thoroughly reviewing security risks before making such a decision.) Terrain is extremely low, so the level, and only a few trees present themselves between the addition of firewalls two buildings. A 20-foot mast, secured to the rooftop with guy wires, is installed on top of each building to raise the is seen as an unnec- antennas above any interference from the trees. essary expense. Figure 1 is a diagram of the components involved in the network. In this, and the succeeding diagrams, all devices used to raise the antenna are represented as towers.

Figure 1. A Simple Point-to-Point Wireless Network.

Wireless Wireless Bridge Bridge

Radio Radio tower tower Library 1-3 miles School

Hub Hub Router T-1 Line

Internet CSU/DSU

Computers File Server File Server Computers

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The general budget for this scenario is presented in Table 6. Project costs are separated for the library and the school. In a real setting, where the wireless link is installed strictly for the benefit of the public library, all the initial costs associ- ated with the project are usually born by the library.

Table 6. Budget Allocation for a Simple Point-to-Point Connection. Wireless T-1 Component Description Cost Cost Library: RF Wireless Bridge, 2Mbps $ 3,000 $ 0 Directional Antenna 350 0 Lightning Arrestor/Protector 400 0 External Cable, 100ft 150 0 20ft Mast, with Installation 1,250 0 Initial Site Survey, no spectrum analysis 250 0 Wireless Installation (half-day) + expenses 500 0 External Cable, 100ft 150 0 T-1 CSU/DSU 0 1,000 In Scenario #1, the Router 0 2,700 v.35 Cable 0 100 break-even point for Installation & Testing ($125/hr, 4 hrs) 0 500 T-1 Line Installation ($750-1,100, waived 0 0 the wireless link will for Texas SW Bell and GTE sites) 10Base-T Category 5 Patch Cable, 10ft 15 15 occur in less than two Library Total: $ 6,065 $ 4,065 years. School: RF Wireless Bridge, 2Mbps $ 3,000 $ 0 Directional Antenna 350 0 Lightning Arrestor/Protector 400 0 External Cable, 100ft 150 0 20ft Mast, with Installation 1,250 0 Initial Site Survey, no spectrum analysis 250 0 Wireless Installation (half-day) + expenses 500 0 T-1 CSU/DSU 0 1,500 Router (assume 2nd port on existing router) 0 0 v.35 Cable 0 100 Installation & Testing ($125/hr, 4 hrs) 0 500 School Total: $ 5,900 $ 2,100

Total One-Time Costs $ 11,965 $ 6,165

Annual connection fee (T-1), Texas, SW Bell 0 3,120

Total First Year Cost $ 11,965 $ 9,285

In this scenario, notice that the break-even point in the comparison between a wireless and T-1 network link will occur in less than two years.

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Scenario #2. Multi-Point Network.

By converting one end of the wireless link to an omni- directional antenna, a simple wireless link can easily be turned into a multi-point connection. In this example a wireless WAN is created among the public library and the various public school campuses: one elementary, one junior high/middle school, and one high school. Figure 2 is a network diagram of the resulting WAN. Table 7 on the next page includes the budgetary requirements to implement it. In this scenario, the wireless costs break even in about two years and six months.

For the sake of illustration, let’s assume that a decision has been made to secure both school and library resources (see Chapter 9 for more information on why this is a good idea). This is done in two steps. First, a firewall is installed at the library and the high school campus (which maintains the Internet connection for the school district). In addition, a separate directional antenna and wireless bridge is installed at the high school site to communicate to the library (using a different spreading code to totally isolate the wireless signals). A separate hub is used to connect the external

Figure 2. Multi-Point Wireless Network with Security.

Wireless Junior High Bridge Hub School LAN LAN Wireless Hub Bridge Radio tower Elementary School Radio

tower 1-2 miles

Wireless Bridge 1 Hub

Radio Wireless LAN tower Bridge 2 Library Radio tower Wireless 1-3 miles Hub Firewall Bridge Radio tower Router Firewall

Hub CSU/DSU Internet T-1 Line

LAN High School

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Table 7. Budget Allocation for a Multi-Point Connection. Wireless T-1 Component Description Cost Cost Library: RF Wireless Bridge, 2Mbps $ 3,000 $ 0 Directional Antenna 350 0 Lightning Arrestor/Protector 400 0 External Cable, 100ft 150 0 20ft Mast, with Installation 1,250 0 Initial Site Survey, no spectrum analysis 250 0 Wireless Installation (half-day) + expenses 500 0 External Cable, 100ft 150 0 T-1 CSU/DSU 0 1,000 Router 0 2,700 v.35 Cable 0 100 Installation & Testing ($125/hr, 4 hrs) 0 500 T-1 Line Installation ($750-1,100, waived 0 0 for Texas school and library sites served by SW Bell and GTE) 10Base-T Category 5 Patch Cable, 10ft 15 15 In Scenario #2, the Packet-Filtering Firewall 3,000 3,000 Firewall Installation and Configuration 400 400 wireless costs break Library Total: $ 9,465 $ 7,465 even in about two School: (4) RF Wireless Bridge, 2Mbps $ 12,000 $ 0 years and six (1) Omni-Directional Antenna 750 0 (3) Directional Antennas 1,050 0 months. (4) Lightning Arrestor/Protector 1,600 0 (4) External Cable, 100ft 600 0 (1) 50ft Tower, with Installation 4,000 0 (1) 40ft Tower, with Installation 2,900 0 (1) 20ft Mast, with Installation 1,400 0 Initial Site Survey, no spectrum analysis 750 0 Wireless Installation (1.5 days) & expenses 1,700 0 Network hub to connect public resources 750 0 (3) T-1 CSU/DSU 0 4,500 (2) Router (assume three free serial ports 0 5.400 (3)on existingv.35 Cable router; if less, additional router 0 300 (3) Installation & Testing ($125/hr, 4 hrs) 0 1,500 (2) T-1 Line Installation ($750-1,100, 0 0 waived; see above for explanation) Packet-Filtering Firewall (if not existing) 3,000 3,000 Firewall Installation and Configuration 400 400 School Total: $ 30,900 $ 9,705

Total One-Time Costs $ 40,365 $ 17,170

(3) Annual connection fee (T-1), Texas, SW Bell 0 9,360

Total First Year Cost $ 40,365 $ 26,530

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networks (the public library and the Internet) to the firewall. The only change required to add other non-school sites is the substitution of an omni-directional antenna for the directional. The primary antenna communicates only with remote school sites.

Scenario #3. Community Network.

One version of a community network with a lot of potential includes the public library, municipal offices, and county offices. This scenario may involve simply the sharing of Internet connectivity, with some minor communications capability—such as e-mail—being made available among various participants as well. It can involve several community sites:

¨ the public library ¨ city hall One version of a ¨ police station ¨ fire department community network ¨ wastewater offices ¨ county courthouse with a lot of potential ¨ county sheriff’s office and jail ¨ county health department includes the public ¨ county road department ¨ chamber of commerce library, municipal,

Not all locations are candidates for wireless connections and county offices. since some have only one or two computers and minimum bandwidth requirements. Dial-up connections over voice- grade lines with 33.6Kbps or 56Kbps modems to a central remote access server will suffice for these.

For illustrative purposes, Figure 3 on the next page shows the municipal area network created for a hypothetical small community in a county seat. The primary purpose of the network will be to share Internet connectivity. The county is the lead agency in the project, with the city participating via an interlocal agreement.

The county courthouse is the “central” site because it provides the best height advantage of all public buildings. An omni-directional antenna will be used at the courthouse to serve all wireless connections. The wireless bridge will have one 2Mbps radio installed, with the capability to add two additional radios in the future. Directional antennas will be installed at each of the remote locations: the county

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Figure 3. Community Multi-Point Network with Security.

Hub Senior Center Hub

Modem Async Router LAN Async Router Modem LAN Youth Center

LAN Wireless Wireless Hub Bridge Bridge Hub

Radio LAN County Roads tower Department Radio County tower Health Department LAN Wireless Hub Bridge

Radio Wireless County Library tower Bridge 1 Hub Radio tower Wireless LAN Bridge 2 Radio tower Wireless Hub Firewall Bridge Modem Radio tower Modem Router Firewall

Hub City CSU/DSU Hall Internet T-1 Line County LAN Courthouse

library, health department, roads department, and city hall. As added security, the wireless bridges will encrypt transmissions. Regular voice-grade dial-up connectivity will be made available to the local Youth Center and Senior Citizens’ Center.

Private data cable already exists to connect other locations. The municipal police department is connected to city hall, next door. The county courthouse annex and the county jail are connected to the courthouse. All together, the network will provide high-speed Internet connectivity to 53 computers. The dial-up service will provide connectivity to five

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more computers in the Youth Center and Senior Citizens’ Center.

A T-1 data circuit will be leased from the local phone company to connect the county courthouse to an Internet Service Provider (ISP) in a city 40 miles away. The monthly fee for the T-1 line is estimated to be $1,000. Commercial T- 1 rates are distance sensitive; the actual cost will vary significantly depending on the distance between the WAN’s central site and the location of the selected ISP. In this scenario we will assume the ISP serves state and local governments and provides shared T-1 access to the Internet for $300 per month. There is ample bandwidth available in the connection to support expansion to more computers in the future. Commercial T-1 rates Table 8 (continued on the next page) shows the general are distance sensi- budget required to initiate this WAN. Note that the cost of the T-1 line is higher in this scenario and the installation tive; the actual cost fee is included. Public school districts, public libraries (no other city or county department qualifies), and telemedicine will vary significantly centers in Texas qualify for reduced rates for leased data circuits as a result of state legislation. For the T-1 cost depending on the comparison, normal commercial rates for T-1 lines are quoted for the three connections besides the public library. distance between the WAN’s central site Table 8. Budget Allocation for a Multi-Point Community Network. Wireless T-1 and the location of Component Description Cost Cost City: the selected Internet RF Wireless Bridge, 2Mbps $ 3,000 $ 0 Directional Antenna 350 0 service provider. Lightning Arrestor/Protector 400 0 External Cable, 100ft 150 0 20ft Mast, with Installation 1,250 0 Initial Site Survey, no spectrum analysis 250 0 Wireless Installation (half-day) + expenses 500 0 External Cable, 100ft 150 0 T-1 CSU/DSU 0 1,000 Router 0 2,700 v.35 Cable 0 100 Installation & Testing ($125/hr, 4 hrs) 0 500 T-1 Line Installation 0 750 10Base-T Category 5 Patch Cable, 10ft 15 15 Packet-Filtering Firewall 3,000 3,000 Firewall Installation and Configuration 400 400 City Equipment and Installation Total: $ 9,465 $ 8,215

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County: (5) RF Wireless Bridge, 2Mbps 15,000 0 (1) Omni-Directional Antenna 750 0 (4) Directional Antennas 1,400 0 (5) Lightning Arrestor/Protector 2,000 0 (5) External Cable, 100ft 750 0 (3) 20ft Mast, with Installation 4,200 0 (1) 40ft Tower, with Installation 2,900 0 (4) Initial Site Survey, no spectrum analysis 1,000 0 Wireless Installation (2 days) & expenses 2,000 0 Network Hub to connect public resources 750 0 T-1 CSU/DSU (1 for wireless; 8 for T-1) 1,000 8,000 (1) Central Router (wireless: low-end, $ 3,050 $ 17,500 up to 2 leased line connections, up to 8 dial- up connections; T-1: up to 6 leased line connections, up to 8 dial-up connections) (3) Remote Router 0 8,100 v.35 Cable (1/8) 100 800 10Base-T Category 5 Patch Cable, 10ft 15 15 Installation & Testing ($125/hr, 4 hrs/16hrs) 500 2,000 (1/3) T-1 Line Installation ($750-1,100, waived for Texas school and library sites 750 2,250 In Scenario #3, the served by SW Bell or GTE) (2) Asynchronous Routers (dial-up connects) 700 700 wireless configuration (4) Modems (dial-up connects) 1,000 1,000 Packet-Filtering Firewall (if not existing) 3,000 3,000 is less expensive from Firewall Installation and Configuration 400 400 County Equipment & Installation Total: $ 41,265 $ 43,765 the outset. Total One-Time Costs $ 50,730 $ 51,980

Annual Costs: County: (1) Library rate, annual T-1 line fee, 0 3,120 Texas, SW Bell ($260/ mo.) County: (2) Commercial rate, annual T-1 0 12,000 line fee, Texas, SW Bell ($500/mo. est.) County: Half T-1 line fee to ISP ($500/mo.) 6,000 6,000 County: Three-fourths Internet access fee 2,700 2,700 County: Four phone lines (dial-up connects, 1,440 1,440 $30/mo each) City: Half T-1 line fee to ISP ($500/mo. est.) 6,000 6,000 City: One-fourth Internet access fee 900 900 Total Annual Costs: $ 17,040 $ 32,160

Total First Year Cost $ 67,770 $ 84,140

This scenario shows the benefit of several entities sharing a single T-1 line via a wireless connection. The wireless configuration is less expensive from the outset.

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Admittedly, there are some design flaws in the comparison. The use of T-1 lines for connecting the four remote points seems a bit overkill. However, using either 56K lines or fractional T-1 lines will result in only minor savings in the equipment costs, with ongoing costs about 40-60% that of T-1 connectivity. The wireless implementation may then be slightly more expensive, but will provide a much more capable connection. Fifty-six Kbps lines will unnecessarily constrain Internet access speed for the remote users.

The wireless connectivity is also somewhat under-powered compared to T-1 lines. Four access points sharing what is approximately 1.5Mbps of bandwidth is not an optimal scenario for many types of network connectivity. But, since these same remote sites will still be limited to 1.5Mbps of bandwidth (or less) when they hit the gateway to the Internet, improving the overall throughput of the wireless system will not improve access speeds to the Internet. If other network services will take place between the central and remote sites, then adding about $28,000 to the project equipment costs will provide about 7Mbps of shared bandwidth, surpassing the service of T-1 interconnections. In this case, the breakeven point will be about one year and ten months after installation.

Conclusion

In these scenarios, we have shown three ways wireless might be used to share scarce resources. Many other entities could be involved in such a project. And there are a wide variety of possible applications. Therefore, the cost and complexity of the network can vary greatly.

Summary

In this chapter we have reviewed all the aspects of building a wireless municipal area network. Specifically, we covered four areas required in budgeting for wireless implementation:

¨ Preparation (the site survey) - check for radio interference - check for radio line of sight - analyze the building for installation difficulties

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¨ Equipment - wireless bridges - antennas (directional and omni-directional) - masts and towers - accessories (lightning protectors and cables) ¨ Installation - building/erecting the masts or towers - mounting the antennas - running a cable from the antenna into the building to the bridge - setting up and configuring the wireless bridge - aligning the antennas and testing the connection ¨ Maintenance - maintenance fee for the wireless bridge, or - extra unit for use if a bridge fails

We also presented three examples of possible community wireless links, with diagrams and projected budgets:

¨ A school-to-library link ¨ A multi-point link connecting all school campuses and the public library, with security ¨ A multi-point link connecting municipal and county offices, including the use of dial-up lines, with security

52 Library Development Division CHAPTER FOUR Where to Go Next

So what’s left?

After examining the need for community networking, the way wireless networking can assist us in sharing electronic resources without incurring large ongoing costs, and the budget information necessary to implement wireless, what is next?

If you’re now interested in developing common community infrastructure (or if you were already interested and you’re just reading to find out how wireless can help), then here are some steps you may want to take next.

¨ As part of your organization’s “infrastructure team,” begin making contact with other local public agencies and see who else may be interested in developing shared infrastructure. Who are the decision-makers in those organizations? Who are the technical people that make network projects happen? ¨ With these other agencies, determine what information resources might be shared. ¨ Hire a consultant, if necessary. Sometimes the amount of work to be done is not worth saving the cost of a consultant. ¨ Determine which buildings may be involved in the municipal area network. Write down street addresses. Produce a scale drawing or map of the area encompassed by the buildings. ¨ Contact various wireless vendors to determine the costs of infrastructure in your community. Supply them with copies of the list of potential sites. Call a vendor or two in your region who installs fiber optic cable and get a price estimate on fiber installation.

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¨ Contact local municipal and county leaders, and the utility company, to determine what right-of-way fees may be incurred if private fiber is installed. ¨ Call the local phone company and determine what the cost of T-1 lines are between the buildings. Determine if ISDN lines will be available soon in your community and, if so, the expected costs. ¨ Gather all the pricing information involved and, with your “infrastructure team,” determine the feasibility of sharing the infrastructure. ¨ If feasible, begin the process of searching for grant opportunities to assist in defraying the initial cost of implementation. ¨ Begin to draft an interlocal agreement to outline the responsibilities of all agencies involved. ¨ Raise local funds, if necessary, to be used as a grant match.

At this point in the process, you’ll be well on your way to finalizing the project. But you’ll also be tired. Find some way to celebrate, relax, and refocus. The rest of the process will involve getting “the paperwork” done.

This is a basic conceptual framework for the process. In most cases one would have to add or delete some steps. Be sure to write down any steps you can think of that may apply in your specific situation.

Here we have to leave you on your own. If you need to learn more about LANs, WANs, and how radio frequency wireless works, please continue with the next part of the manual. Otherwise, turn to Appendix B and look up some of the RF wireless equipment manufacturers’ contact information. Then make some phone calls or surf the web.

Good luck on the journey!

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