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A.STUDENT REPORTA USERS GUIDE TO LOCAL AREA

NETWORK CONNECTIVITY

. MAJ STEPHEN V. BROWN 86-0365

"insights into tomorrow"C.7)

*. . * * * - - - -.-

DISCLAIMER

The views and conclusions expressed in thisdocument are those of the author. They arenot intended and should not be thought torepresent official ideas, attitudes, orpolicies of any agency of the United StatesGovernment. The author has not had specialaccess to official information or ideas andhas employed only open-source materialavailable to any writer on this subject.

This document is the property of the UnitedStates Government. It is available fordistribution to the general public. A loancopy of the document may be obtained from theAir University Interlibrary Loan Service(AUL/LDEX, Maxwell AFB, Alabama, 36112) or theDefense Technical Information Center. Requestmust include the author's name and completetitle of the study.

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-- Reproduction rights do not extend toany copyrighted material that may be containedin the research report.

-All reproduced copies must contain thefollowing credit line: "Reprinted by .'

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-If format modification is necessary tobetter serve the user's needs, adjustments maybe made to this report--this authorizationdoes not extend to copyrighted information ormaterial. The following statement mustaccompany the modified document: "Adaptedfrom Air Command and Staff Research Report

(number) entitled (title) by(author)

-This notice must be included with any Ereproduced or adapted portions of thisdocument.

- REPORT NUMBER 86-0365 "TITLE A USERS GUIDE TO LOCAL AREA NETWORK CONNECTIVITY

AUTHOR(S) MAJOR STEPHEN V. BROWN, USAF i

FACULTY ADVISOR MAJOR CHARLES E. WILLIAMS, ACSC/EDOWC

DTIC

Submitted to the faculty in partial fulfillment of AP .518

requirements for graduation.

AIR COMMAND AND STAFF COLLEGEAIR UNIVERSITY :-

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MAXWELL AFB, AL 36112 AC W

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Or- ADDRESS (City. State and ZIP Code) I pdiabe 7b. ADDRESS (City, State and ZIP Code)

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11 TITLE (include Security claurficationu) A 5 H IV

TO LOCAL AREA NETWORK CONNECTIVIY____________________12I PERSONAL AUTHORS)

BROWN, STEPHEN V. MAJOR, USAF13..TYP QPREPRT 3b. TIME COVERED jtDATE OF REPORT (Yr., Mo.. Doy ~15. PAGE COUNT1aTYEOREOT TFROMA TO - 114 s'f~

IS SUPPLEMENTARY NOTATION

17 COSArI CODES 18. SUBJECT TERMS rf(nfuC an rwwerm ifitec.,.., and Identify by block number)IE.0 GROUP SB R

19. ABSTRACT (Continue on reverse if necemary and identify by block, number) '

The users guide on Local Area NetworiC connectivity is designedto provide functional managers with a basic overview of local.area networks. Included is information concerning networkfeatures regarding functional applications, who the majorAir Force players are (MAJCOM and base level), and appropriatejustification procedures for anyone attempting connectionto a Local Area Network.

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UNCLASSIPED/UNLIMITED C SAME AS AfPT CSOTIC USERS 0 UNCLASSIFIED

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____"_____PREFACE i

I first became interested in the functional aspects ofcommunication networks during my recent assignment to HO AirForce Manpower and Personnel Center. During my tour there Iwas involved in developing an office automation system

i designed to support the existing base level personnel system.The functional definition of the future personnel system

*. included a requirement to interface with every base level. functional organization requiring personnel information. My

subsequent work with the existing base level personnel systemalso exposed me to the functional impacts a supportingcommunications network can have on an operation. Many of thebase level automated data systems (ADSs) are currently in aposition to redesign their systems to take advantage of thenew base level Sperry 1100/60 computers (Phase IV program).Much of the new design work will involve shared dataapplications requiring communications access to variousfunctional systems. The move towards in-system processing isalso being driven by Air Force efforts to get out of thepunched card business. The single most cost effectivecommunications networking configuration available to supportthese new requirements is the Local Area Network (LAN).Unfortunately, LANs do not exist at most Air Force bases and,although cost effective to operate, they can be quiteexpensive to install, especially if the base cable plantalready exists.

This handbook is intended for the functional manager who*' is confronted with the prospects of LAN connectivity.

Although LANs are not currently installed at Air Force bases,. they are being designed, and planning for future installations

is being done. An organizational structure has beenestablished within the Air Force Communications Command (AFCC)to develop and maintain future Air Force %tandard LANs. Assuch, many, if not all, functional systems will eventually betied together through base level LANs. This handbook willassist the relatively uninitiated (sysfems wise) functional rmanager in determining what a LAN can do and who on the baseis responsible for LAN operations. It also provides some

- details needed to justify connectivity to a LAN.

°'- iii "'

SCONTINUED________

I greatly appreciate the assistance provided by manypeople in developing this handbook. In particular, Major EdWilliams, my advisor; Mrs. Joan Bowden, my sponsor; and othermembers of the staff of the Air Force Small Computer/OfficeAutomation Service Organization, Gunter AFS, AL.

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"-_ _ ABOUT THE AUTHOR

-Major Brown was commissioned in 1973 through the ReserveOfficer Training Corp (ROTC). His first assignment was toMcClellan AFB, CA with the Air Force Audit Agency (AFAA). Asubsequent assignment with the AFAA at RAF Upper Heyford, UK,exposed him to many of the base level functionalorganizations. In 1979 he was assigned to the Air ForceInstitute of Technology (AFIT) and sent to the University ofArizona. Upon graduation he was assigned to the Air ForceManpower and Personnel Center (AFMPC) and began working on afuture office automation system for base level personneloffices. He established and monitored several functionalprototypes for this new office automation system; collectingand analyzing much of the data used to functionally justifyfull-scale development of this program. After serving as theExecutive Officer to the Director of Manpower and PersonnelData Systems, he became chief of the Base Level MilitaryPersonnel System. As such, he was responsible for theday-to-day operation and maintenance of the Base LevelMilitary Personnel System which supports base level commandersand managers with a wide range of personnel data. He holds aBSBA in Accounting from Auburn University and an MS inManagement Information Systems from the University of Arizona.

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Preface .................................... iiiAbout the Author v ""........................vList of Illustrations ................... ........... viii

CHAPTER ONE--INTRODUCTION TO LOCAL AREA NETWORKSWhat is a LA N? ........................................... I

Network Topologies. . .. a . .. .. .. .. .. .. ................ *.2

Muing i-o. ............... ............................ 3 .

Star .............. s...........................3

Te ................................... 4

Al ternatives ...... m...... *........ ...... P............. 5

CHAPTER TWO--INTRODUCTION TO AF LANS AND ALTERNATIVECOMMUN I CAT IONS

Current Communications Networks at Base Level ............ 7Air Force LA s........................................... 7Systems Best Suited for LANs ............................. 9

CHAPTER THREE--AIR FORCE LAN OPERATIONSAir Force LAN Operations ..... ......... 11

HO AFCC .............................................. it - -H O ESD .. . . . . . . . . . o .. .. .. .. . .. .. .. ..1

BIDDSP ..., .... ..... ....... ,.. ................... 11Ele c tronic Installat ion Division. .................... 11Standard Information System Center ................. 12

Base Level LAN Players .... .................... ......... 12IPC ..... .. .... ...... . e........ a...... ... ......... 12

LAN Manager ................................... 13

CHAPTER FOUR--CRITERIA ESSENTIAL FOR CONNECTIVITY TO A LANStandards and Protocols ........................... .... 14Hardware Considerations....... o . ....... ....... ... .15Security Considerations ......... . .. .. ....... ...... 16Maintenance ..... 1............................ 16Installation/Connect ion .............. .......... 17

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* ~~CONTINUED________

CHAPTER FIVE--REQUIREMENTS JUSTIFICATIONFunctional Requirement.................................... 18Justification Process ................................... 19

SBIBLIOGRAPHY ..................... . ..................... 21

I NDEX ....................... .............* * ............... 23

vi L

____ ___ ___LIST OF ILLUSTRATIONS _ _ _ _ _

FIGURES

FIGURE 1.* --Ring Topology ....... .........*..............3

FIGURE 1 .2--Star Topology. . .. .. . .. ................. . .. .4FIGURE 1 .3--Tree Topology .. .. . .. ... .. .. .. . .. ............. 4FIGURE 1 .4--flesh Topology. .. .. . .. . .. .. ...... ........ . .. .5FIGURE 2.1--View of ULANA LANl .. .. . ... .. .. .. .. ............ B

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Chapter One

INTRODUCTION TO LOCAL AREA NETWORKS

One of the most challenging concerns for many functionalorganizations in today's Air Force is computerization. Therecurrently exist over forty separate automated data systems(ADS) that support functional applications running on thestandard base level computer. The tremendous growth inmicrocomputer technology in recent years has allowed many ofthe base level functional organizations such as personnel,accounting & finance and maintenance to pursue development ofoffice automation programs. The new functionally automatedsystems are being built with a wide range of differentcommercially procured hardware and software. The onerequirement that these systems all have in common is the needfor communications access to shared information. That meansthey have to be able to communicate with one another. Thereare numerous communications networking schemes availabletoday; the one which the Air Force is moving toward to moreefficiently cope with the problems of a multi-source systemsenvironment is a Local Area Network.

What is a LAN?

A local area network is a communication facility thatcovers a limited topology (physical configuration), andinterconnects in an effective manner different types ofservers (host or mainframe computers) and workstations(distributed terminals), more particularly personal andprofessional computers. In width it varies from 100 meters to10 km depending on the architecture. Simply put, local networkis a term referring to the total communications environmentwhich connects dissimilar computers or data systems in aspecifically constrained area.

You can see the application for LANs at any Air Force

".C" Base. The installation of a single communications network

that links the base level computers (hosts) to the numerousfunctionally designed office automation systems (workstations)

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has many advantages. First, a common communications networkis cheaper than point-to-point architecture and much more

efficiently maintained. Secondly, it provides a facility for WKmore efficient office operation through reduced data entry andkeystroking. Finally, data system storage and retrievalproblems are reduced through access to shared information. Thefollowing generalized characteristics help to better define

LANs:

- High data transfer rates

- Limited geographic scope

- Equal access by all user devices

- Ease of reconfiguration and maintenance

- Good reliability and error characteristics

- Stability under high load

- Compatibility with a variety of equipment

- Relatively low cost

Now that you have a feel for what a LAN is, we need todescribe network configuration or topologies, since that's thepart of a LAN that makes it unique from other networks.

Network Topologies

The arrangement of computer resources and communicationfacilities is known as network topology. Unlike a long-haulnetwork which is designed to support an unconstrainedtopology, LANs are designed to support a specific topology,i.e., a typical Air Force base. An additional feature thatmakes LANs unique to other networks is its use of a*broadcasting' versus point-to-point or multi-point topology.Most networks use a central facility to determine whereinformation is to be routed and only the intended receivergets the message. LANs are designed to "broadcast"information to all users on the network and they in turndetermine if the information is addressed to them. The most icommon LAN configurations in use today are the ring, the star,

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the tree, and the mesh.

a Ring

The ring network is a pattern of computing elements(nodes) arranged in a circle and connected by a communicationmedium (link). See Figure I.I. Communication between nodesis generally uni-directional and must pass from node to node .until it reaches its destination. Rings are best suited forenvironments with a small number of nodes operating at highspeeds over short distances.

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Figure I.I. Ring Topology

Star

The star network is the only "nonbroadcast* topologycurrently available as a LAN. The configuration has a centralnode connected to every other receiving node in the network.See Figure 1.2. All communications control is performed atthe central node which essentially acts as a switch-board.Star networks are usually driven by large mainframe systemsand can handle a relatively high number of nodes. Potentialvunerabilitity stems from the network's entire dependabilityon the central node to control all communications routing.

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Figure 1.2. Star Topology

The tree network (also called bus) arranges the nodeslike leaves on a tree. See Figure 1.3. The originating nodetransmits the message along the communications link (bus) andeach node reads the address as it goes by. The tree networkis probably the most commonly used LAN topology and bestserves a large number of nodes over a relatively shortdistance. One of the major advantages of this configurationis that single node failures have no affect on the overalloperation of the network.

Figure 1.3. Tree (Bus) Topology

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MeshThe mesh network is basically an unconstrained hybrid or

nonspecific network. The nodes are connected by patternswhich are most economical and can be redundant if required.See Figure 1.4. Mesh networks are not normally used in LANsand are more commonly found in long-haul networks.

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Figure 1.4. Mesh Topology

Alternatives

The trend toward local area networking seems to be drivenby two major concerns: (1) interconnectability, and (2)cost. It's relatively easy to see that these two features ofLANs are interdependent. The proliferation of computertechnology throughout the Air Force is continuing to increaseat an exponential rate and requirements for shared informationare common place. If all users need access to one anothersdata, then using a single common communications line wouldprovide for interconnectability at a reduced cost. However,there are other network configuration that, deiending on the

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requirement, provide efficient, cost effective communications.Let's look at a few:

Point-to-point - This networking configuration is simplytying two nodes (terminals/computers) together with a singlecommunications line. The advantages are speed (depending online speed capability) and maintainability. The disadvantagesare cost (depending on the number of terminals/computers beingconnected) and restriction to only one other device. If yoursystem is small with minimum access requirements to a variety /-..-.of other systems, this configuration is probably mostsu i table.

Multi-Doint - This network configuration is designed totake advantage of shared communication lines and supports twoor more nodes. The major advantage of a multi-point networkis reduced line cost. The disadvantages are reduced speedcaused by line contention among the users, and the fact thatif the line goes out it takes more than one node down. Ifyour system supports multiple terminals at remote locationsand is not dependent on large volume, high speed transactions, . .-.a multi-point configuration may be the most suitable.

1 .

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Chapter Two

INTRODUCTION TO AF LANS AND ALTERNATIVE COMMUNICATIONS

Current Communications Networks at Base Level

The Base Communications Transmission and DistributionSystem (BCTDS), commonly referred to as the Base Cable Plant,is the collection of all base wire communications media. Ithandles the operation, maintenance and bookkeeping of basecommunications wire resources. Most base level communicationrequirements are met by direct cable link or point-to-pointnetworking schemes. There are also some multi-pointnetworking schemes in use. The concept of a local areanetwork has evolved due to the proliferation of ADP equipmentrequiring connectivity to numerous other informationprocessing system equipment. Can you imagine the networkingnightmare involved with point-to-point communications forevery piece of equipment currently being installed to supportfunctional systems?

You may have heard the term DON (Defense Data Network) atyour base. This is a dedicated long-haul communicationnetwork providing service from base to base, not intrabasecommunications. You may have a requirement for interbasecommunications which will be satisfied by a LAN hook-up toDDN.

Air Force LANs

HO AFCC and HQ ESD have jointly formed the Air ForceMission Effective Information Transmission System (MEITS),formally known as the Air Force LAN Systems Program Office(AFLANSPO), which has been tasked to develop a unified LANarchitecture (ULANA) for the Air Force. In essence what thisgroup is doing is developing a standard family of LAN productsfor Air Force use. The network will have a broadband (ie.coaxial cable) distribution system, a family of standardnetwork interface units and a separate network managementsystem. See Figure 2.1.

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Figure 2.1. View of ULANA LAN

ULANA will provide all the hardware/software required toconnect a variety of heterogeneous data, voice and videodevices, satisfying most Air Force requirements. Because fullULN development will probably take several years, plans havebeen established to procure a standard interim LAN. Theseinterim LAJs should be available in 1986 and will provideoff-the-shelf network interface units (NIU) for use withexisting broadband distribution systems.

The first Air Force operational LAN has recently beeninstalled at Mather AFB. This LAN is scheduled to be

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certified in Feb/Mar 86 and is designed to operate as a testbed for functional application prototyping in a LANenvironment. It is not ULANA certified, but will allow usersat Mather to test future system concepts supported by LANtechnologies. The LAN can support over 500 nodes and has beenrouted to 49 buildings on the base. Currently, both theaccounting & finance, and personnel functions are planning toprototype new office automation systems using the LAN as theirbackbone communications support. The LAN will eventually betied to the Sperry 1100 host base computer to provideconnectivity to existing base level systems.

Future plans are underway to install a second Air Forceoperational LAN at Moody AFB sometime in late 86. The gameplan is to build a fiber optics vice coaxial cabledistribution system to support continued functionalapplications prototyping. The Moody LAN should be operationalsometime in CY 87.

Systems Best Suited for LANs?

We've already described several system's features, suchas speed (data transfer rates), volume, andinterconnectability, which are critical criteria indetermining the functional utility of a LAN. Depending on theconfiguration and how much money is invested, LANs canundoubtedly be designed to support practically any functionalapplication. But who is going to develop a sophisticated LANto support communications between two common terminals? Sothe question is, "Do I need a LAN to support my specificapplication?" In private industry you are going to pay foryour network, so that question is critical. In the Air Forceyou won't be paying for the LAN (if available) per se, but youwill have to pay for the system hardware/software required toconnect to a LAN. You're also going to pay with systemsimpacts which are caused by network characteristics. Let'stalk about some systems' features which are best suited forLANs.

First, moderate data transfer rates are best suited forLANs; they should not be extremely high. Remember! LANs areshared communication networks with built-in access controlswhich take time to respond. If you find yourself on acongested LAN network with numerous other functional users,

9

You're probably going to experience some time delays if

you're operating customer service terminals in the accounting& finance office of the future, and you're waiting thirtyseconds for computer responses you'll be paying for the LAN.If your system requires high speed data transfer, direct cablelink may be the most cost effective network alternative.

Secondly, systems that deal with a high volume oftransactions can experience the same problems as previouslydescribed. Although, depending on the particular application,this may not be a problem. If response time is not critical,then delays caused by increased volume are not a problem.However, overall response time for everyone on the network isaffected, which will undoubtedly impact the users.

A third consideration is interconnectability. The LAN isa communications network which facilitates electronicconnectivity. The one thing it cannot do is interfaceincompatible functional applications. The substantial benefitof LAN technology is that it provides this interconnectivitywith numerous different types of computer equipment. It'stherefore best suited for systems having interfacerequirements with more than one external system that supportscompatible applications.

The final consideration of interest in determining LANutility is system expansion. As a rule of thumb, LANs canmore beneficially support systems that are expanding or beingreconfigured. Adding terminals to a LAN supported system isalmost as easy as plugging in your typewriter. On the otherhand, adding terminals to a system supported by apoint-to-point network configuration requires starting fromscratch and installing all required connections.

In summwary, if you have a dynamic system requiringinterconnectivity with several other systems and can live withsome response time degradation, then a LAN could provide acost effective communications alternative.

10. *.* - -.

Chapter Three

AIR FORCE LAN OPERATIONS

Air Force LAN Operations

Now that you have a feel for what a LAN is, what it cando, and what's available in the Air Force, let's talk aboutwho's in control. There are several key players at base levelthat can get you up to speed on what's available at yourspecific base, but before we introduce them, let's talk aboutthe command players.

HQ AFCC

AF Communication Command has the overall responsibilityfor guidance and direction in LAN planning. They'reresponsible for design, development, acquisition,implementation, operation, and maintenance of all Air Forcecommunication networks, including LANs.

HO ESD (MEITS)

You were introduced to this organization in Chapter Two.Remember, they're the folks who have been tasked withdeveloping a standard Air Force LAN architecture.

Base Information Diaital Distribution Systems ProgramOffice (BIDOSPO)

This office is under the direction of AFCC and hasassumed responsibility for implementation of ULANA. The MEITSorganization has direct responsibility for the development ofULANA and will pass the project to the BIDDSPO for AirForce implementation.

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Electronic Installation Division (EID)

These folks are at Oklahoma City, OK and act as the focalpoint for implementation of LANs Air Force-wide. They're

known as the Implementation of LANs (ILAN) Program ManagementOffice and are basically responsible for integrating all majorcomponents of LANs. You won't be dealing with them unlessyou're the LAN manager at your installation.

Standard Information System Center (SISC)

Formally known as the AF Data Systems Design Center atGunter AFS, AL, they provide technical assistance to other LANplayers. The Air Force Small Computer/Office AutomationService Organization (AFSCOASO), as part of the Data SystemsDesign Office, is the organization chartered to preparetechnical specifications for network interface. They alsomanage the Gunter LAN as part of the AFCC test bed for LANdeve I opmen ts.

Base Level LAN Players

We've just described the organizations basicallyresponsible for design and development of future AF LANs. Asa functional manager of a system, your contacts with theseorganizations will be minimal. The base level organizationcharged with the responsibility for the day to day operationof communication networks is the Information Processing Center(IPC).

LEC

The Information Processing Center is the new squadronlevel organization which incorporates the old communications.squadron and the data automation function (Data ProcessingInstallation, DPI). Their job basically entails management ofcommunication and data automation facilities. This is theorganization you'll have to deal directly with in developingand implementing specific LAN connectivity requirements. Bythe way, they do have specific responsibilities to you as acustomer. AF Regulation 700-7 section D outlines IPC

12

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responsibilities in the area of customer support. After ageneric description of customer support, they are charged withproviding customers training on the use of availableinformation systems and providing customer education onavailable services. If and when LAN technologies arrive atyour particular installation, these are the folks who can tellyou what is available and provide detailed information as torequired systems specifications for network connectivity.There is one other critical player you should be aware of, theLAN manager.

| ~A Maona.,t iL-NDuring the initial prototype phase of Air Force LANs the

primary figure in LAN development and operation has been theLAN manager. Although no current authorizations exist for aLAN manager per se, you should be able to find someone whoWears the title at the Information Processing Center. The LANmanager will be basically responsible for day to day LANoperation and should serve as a point of contact forfunctional managers interested in connectivity. More likely,this is the individual who will review and assess functionalrequirements and justification for LAN support. Chapter Fivewill explain the current functional justification process. t"

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Chapter Four , .

CRITERIA ESSENTIAL FOR CONNECTIVITY TO A LOCAL AREA NETWORK

This chapter is designed to provide you, the functionalmanager, with a limited background concerning networkconnectivity criteria. Although it's certainly not necessaryfor a manager to understand details of how data is transmittedthrough the network, or what hardware and maintenanceconsiderations are critical, general knowledge of these areascan arm you with enough information to ask the right questions Pp..to those people who are designing and implementing yoursystem.

Standards and Protocols

The term standard is basically just what it implies - thecommon use of a particular function, code, or piece ofequipment, throughout an industry. An important concept tounderstand is the electrical standard. Computers communicateinternally and externally via digital signals. Electricalvoltages are used to determine bits of information, which arethen processed by computer systems. Each system has aspecific voltage level which must be maintained within astandard range in order to interface with each other. Themost common industry standard code for this electrical currentis the Electronic Industries Association RS-232-C. This codeprovides a common description of what the signal coming out ofand going into a computer/terminal will look like.

Another concept you need to be aware of is the differencebetween asynchronous and synchronous transmissions. Wheninformation is transmitted there needs to be a way to indicatethe start and stop of each transmission. Asynchronoustransmissions attach a start and stop flag to each characterof information transmitted. Synchronous transmissions add astart and stop flag to a continuous stream of characters.Synchronous transmission is faster, and better serves highspeed transmission systems, but obviously requires moreprecise timing which is controlled with additional

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communications software.

The final concept involved in data transmission that youneed a basic understanding of is communication protocols.Protocols are communications software that handle informationaddressing, identification of message termination, and messageaccuracy validation. Protocols are standardized so thatinterfacing users can decipher information being transmittedto each other. If standard protocols are not used you can seethat systems which are interfaced via communication facilitieswould still be incapatible. It's also important to note thatprotocols are designed to facilitate transmission ofinformation between stations as well as controlling theoverall information flow or routing on the network.

Hardware Considerations

Let's take a look at the hardware involved in supportingconnectivity to a LAN. Assuming the LAN has been implementedand a drop point has been installed at your facility, the onlyadditional hardware requirement for connection to the LAN isfor a Network Interface Unit (NIU). The NIU is a Nblack box"containing physical connectors and software.which provide thenecessary protocols to allow external equipment to beconnected to the LAN. Remember, equipment that does notsupport the industry standards discussed above, is extremely L

difficult to interface with other non-standard equipment.Current Air Force plans are to authorize NIUs as a Table ofAllowance equipment item. The size and cost of the NIUs varywith the number of connectors and amount of software provided.As a Table of Allowance item the cost of the NIU will be borneby the user.

Another hardware consideration concerning LANconnectivity is a LAN to LAN connection. If your functionalsystem is already supported by a LAN, for instance, theaccounting & finance office automation system may be supportedby a small LAN within the accounting & finance office, you mayrequire a gateway processor. This processor houses additionalsoftware and memory capacity for interfacing dissimilar LANs.The additional software and memory could be embedded in theNIU or your host computer system, but it has to be part ofyour checklist regardless of where it is housed.

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Security Considerations

The state of the art in LAN technologies would makeprocessing classified information across the network too rrisky. Depending on the transmission media, i.e., wire,coaxial cable or fiber optics, differing levels of securitycan be obtained. Coaxial cable, which is currently the mostcommon media used, requires a physical tap into the network inorder to intercept or destroy information being transmittedover the network. Encryption devices would make it difficultto effectively intercept the information, but would not stopintruders from destroying information. Normal passwordprotection schemes built into existing software can protectthe integrity of systems residing on separate host computersand periodic security analysis functions can be performed ondata processed over the network.

Although the first Air force LANs will not supportclassified processing, they will provide enough security toprocess the bulk of the Air Force's data transmissionrequirements.

Maintenance

As you know by now, LANs are generically considered ascommunication systems and not as an extension to a vendorspecific system. Therefore, maintenance responsibilities willrest with the organization implementing the LAN. TheInformation Processing Center will be responsible formaintaining base level LANs installed by HO AFCC. Oneconsideration you must be aware of is that if you purchase aLAN to support a user specific system, i.e., accounting &finance's office automation system might be supported by asmall LAN within the accounting and finance function, then,you the user, will probably be responsible for maintenance.

Another important consideration involving maintenance ofLANs is obviously the type of LAN and topologies used inconfiguration of the LAN. Some LANs are more reliable thanothers, the difference being type of transmission media, i.e.,wire, coaxial cable or fiber optics, and amount of hardwareand software necessary to operate the LAN. LANs in generalcan be configured to provide users greater network reliability

16

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than point-to-point or multi-point networks. In most cases,breaks in the transmission media for LANs are easy to find andfix compared to todays cable plant problems of having tosingle out one or two wires from a cable housing severalhundred.

Installation/Connection

Several considerations must be carefully reviewedinvolving facilities modifications before a user can connectto a LAN. First, does the base cable plant already providecommunications support to your facility? Is the LAN routed toyour facility? If the answer is no, then you need t-) submitan Information Systems Requirement Document (ISRD) to theInformation Processing Center requesting your facility beestablished as a LAN drop site. You should do this as earlyas possible; from past experience, it can take up to a yearfor communications support at some installations. Facilitiesmodifications required to support automated systems dependprimarily on the size and power of the system being installed.Modifications range from additional electrical circuits toincreased air conditioning. The point here is thatcommunication requirements are part of that checklist, andneed to be worked early in the game. It is extremelyfrustrating to have your entire system ready to go and thenfind out you don't have a communications line in your buildingthat will reach the LAN.

4.

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Chapter Five

REQUIREMENTS JUSTIFICATION

If you've read the first four chapters, then you probablyhave a basic understanding of Local Area Networks, what theycan do, and some of the considerations involved in theiroperation. Now it's time to find out how the justificationprocess works.

Functional Reagirement

The first thing required in this process is to determineif a LAN is really required to functionally support yourparticular data system. As previously mentioned, your systemmay already be optimally supported with the currentcommunications network. So, let's list some of the basicfunctions that a LAN should support. The typical applicationsinclude: electronic mail and calendar management, wordprocessing, facsimile, data entry and voice mail. Some otherfunctional requirements that LANs should support includegrowth potential and access to other networks.

For starters, you should analyze the requirement bydefining your objectives. What is your system supposed to do?"Are you an information processing operation, providinginformation to other users; or are you retrieving informationfrom other sources? You may find that determining theinformation needs of your organization in terms of production,storage and uses is helpful in defining your objective.Secondly, describe the system. Outline the information flowof your system. What organizations are part of thisinformation network? Outline functional requirements forspecific information. For example, personnel rostersspecifying required immunizations are generated from the baselevel personnel system and provided to the hospital. Onceimmunization information is updated at the hospital, it'sreturned to the personnel system and maintained on file forfurther use. A description of your information network canreally help you nail down your functional requirements. The

-S..,%

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*. . . . . . . . . . . . .

Sfinal consideration in justifying access to a LAN'is to

determine communication needs. Although not a functionalrequirement associated with your system, communication needs

• should be outlined in terms of compatibility and capacity.Compatibility is defined here in terms of system

.: .:compatibility, i.e., personnel and accounting & finance mayhave a communications )ink connecting them, but it does nogood unless the systems are compatible. You'll also need todetermine how much information is being transferred. You mayrecall in chapter 2, we discussed transfer rates impacting onthe functional ability of a system. Remember, defining yoursystem objectives, describing your information network, anddetermining your communication needs are all criticalcomponents in your ability to functionally justify your

~systems connectivity to a LAN.

Justification Process

The justification process for LAN connectivity isdescribed in AFR 700-3, chapter 2. It basically states thatan Information Systems Requirement Document (ISRD) must besubmitted by the functional user. The ISRD identifies anddescribes, the required capability, justifies the need, andserves as the validation and approval document. Details forcompleting a ISRD (AF Form 3215) are found at Attachment I of

. AFR 700-3 and require the following information for justifying-'. the need:

" -Major functional objectivesWI".'." -- Describe your organizational responsibilities in

terms of information requirements. Explain what your systemdoes and why.

-Mission impacts if requirement not supported-Here's where you want to describe the functional

impacts, i~e., accounting & finance mission is delayed,duplicated or not accomplished because access to certaininformation from the personnel system is not available. Areyou doing manual work because in-system information is not.avai labl e?-

Tangible benefits-- Relate functional and system benefits associated

- .:with connection to the LAN. Productivity increases, if

• o..4:: .,

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+ o.\• , o.finalo..con..siderati o . .. . .in.us if ing ac es to a LA ..s t..o .°• .-- %.°

Z.quantifiable, should be included.

Improvements in capabilities-- This ties directly to tangible benefits and

increased productivity. It also includes being able toprovide more accurate, timely information to those requiringyour services.

- Identify cost savings 1-- Can your system do the job with less equipment

through more efficient communications access? Is the LANless expensive than your current communications configurationor other alternatives? Here's where you can try to put aprice tag on increased productivity and other tangiblebenefits.

- Identify required system interfaces-- Describe interface requirements in terms of

functionality. If you have a current manual interface whichcould be automated if the communications link existed, itshould be included in this identification process.

Any additional systems development necessary to supportr equ i rement

-- As a functional person you'll probably need somehelp on this one. If the folks at the IPC draw a blank, havethem contact your functional system developer at SISC, GunterAFS, AL.

- Alternatives-- Lay out any alternatives that you're familiar with.

If you've done your homework, the only reasonable alternativewill be connection to a LAN.

Approval authority for LAN connectivity has beenestablished at the MAJCOM and MEITS level. Currentlyprocedures will require the ISRD to meet the InformationSystems Requirement Board at your specific installation andif validated, forwarded to MAJCOM and MEITS for approval and"overall management and coordination of user LAN requirements.

The base information systems staff officer or base levelLAN manager located at the Information Processing Centershould be able to assist you in preparing the ISRD.

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~BIBLIOGRAPHY"

A. REFERENCES CITED

Books

1. Chorafas, Dimitris N. Designing and Implementing LocalArea Networks. New York: McGraw Hill Book Co., 1984.

2. Derfler, Frank J., Jr., and Stallings, William.A Manager's Guide to Local Area Networks.Englewood Cliffs, N.J. Prentice Hall Inc., 1983.

3. Doll, Dixon R. Data Communications. New York: JohnWiley & Sons, 1978

4. Fritz, James S., Kaldenbach, Charles F., and Progar, LouisM. Local Area Networks - Selection Guidelines.Englewood Cliffs, N.J. Prentice Hall Inc., 1985

Official Documents

5. AFSCOASO, The Air Force Manager's Guide to LAN Planning.Gunter AFS, AL: Data Systems Design Office, April

.. 1985.•

6. AFSCOASO, Data Communications Planning Guide. Gunter

AFS, AL: Data Systems Design ffice, June 1985.

7. U.S. Air Force Communications Command, Systems OperationsConcept of Air Force Local Area Networks. Scott AFB,IL: July 1984.

B. RELATED SOURCES

Books

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........................................... {-- i -.................... ..nd ..................

66CONTINUED__

Tropper, Carl. Local Computer Network Technologies. NewYork: Academic Press, 1981.

Official Documents

Air Force Regulation 700-3, Information Systems RequirementsProcessing, 30 Nov 1984.

Air Force Regulation 700-7, Information Processing CenterOperations Management, 15 Mar 1985.

U.S. Air Force Communications Command, Advanced Concepts BaseProaram Lessons Learned. Gunter AFS, AL: Interim Report,April 1985.

U.S. Air Force Communications Command, Data NetworkManaaement's Options and Opportunities. Scott AFBIL: Research Report, December 1983.

Unpubl i shed Mater i al s

Lundquist, Charles Q., Maj, USAF. NA Handbook for Local AreaNetworks". Research study prepared at the Air Command and

Staff College, Air University, Maxwell AFB, AL, 1985.

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.,

INDEX __

About the Author, vAir Force Communications Command (AFCC), 7, 11, 16Asynchronous, 14Automated Data Systems (ADS), IBase Communications Transmission and Distribution

System (BCTDS), 7, 17Bibliography, 21BIDDSPO, 11Broadcasting, 2Coaxial cable, 9, 16Data transfer, 9Electronic Installation Division (EID), 11Electrical standard, 14Fiber optics, 16Installation Processing Center (IPC), 12, 20Information System Requirement Document (ISRD), 17, 19, 20LAN Manager, 13, 14, 20Maintenance, 16Mission Effective Information Transmission

System (MEITS), 7, 11, 20Mesh network, 5Multi-point, 2, 6, 17Defense Data Network (DDN), 7Network Interface Unit (NIU), 8, 15Nodes, 3, 4Point-to-point, 2, 6, 7Preface, iiiProtocols, 15Prototypes, 9, 13Ring network, 3Response time, 9, 10Security, 16Standard Information System Center (SISC), 12, 20Sperry 1100, 9Star network, 3Synchronous, 14Table of Allowance, 15Table of Contents, vi rTree network, 4Topology, 1, 2, 3, 16Unified LAN Architecture (ULANA), 7, 8, 9

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