MCSE Traing Guide Networking Essentials - Ravi Thanki

01.919-x FM8/28/98 10:08 AMPage iTRAINING GUIDEMCSESecond EditionNetworkingEssentialsExam: 70-058Glenn Berg

04.919-x Part18/28/98 10:59 AMPage 1P A R TSTANDARDSANDTERMINOLOGY1 Networking Terms and Concepts2 Networking StandardsI

05.919-x CH01.i8/28/98 11:26 AMPage 3OBJECTIVESChapter 1 targets the following objectives in theStandards and Terminology section of the NetworkingEssentials exam:Compare a client/server network with a peer-topeer network. This objective makes sure you are familiar with thetwo main network classification models.Define common networking terms for LANs andWANs. The purpose of this objective is to make sure people working in the networking field understand thedifference between a local area network (LAN) anda wide area network (WAN). These terms are themain topics of discussion throughout this chapter.Compare a file and print server with an application server. This objective makes sure you are aware of the different types of servers in the field of networking.C H A P T E R1Networking Terms andConcepts

05.919-x CH01.i8/28/98 11:26 AMPage 4OUTLINENetworking Concepts and Components7Network Services189Basic Connectivity ServicesRedirector ServiceServer Service181919Centralized Computing9File Services20Distributed Computing11Collaborative Computing12File Transfer ServicesData MigrationFile ArchivingFile-Update Synchronization23242525Printing Services26Application ServicesDatabase ServicesMessaging/Communication ServicesEmailVoice MailFax ServicesGroupware26283031313131Models of Network ComputingNetwork Models: ComparingClient/Server and Peer-to-PeerNetworking Configurations13Client/Server Based Networking13Peer-to-Peer Networking15Local and Wide Area Networks16Local Area Networks (LANs)16Directory Services32Wide Area Networks (WANs)16Security Services33Intranets and Internets17Chapter Summary36

05.919-x CH01.i8/28/98 11:26 AMPage 5S T U DY S T R AT E G I E S. You need to be very familiar with the terminology used throughout this chapter. This terminology serves as a basis for the rest of the bookand for the exam. Many different services are explained in thisbook. Be prepared to understand the keydifferences between a file and print serverand an application server, as well as the differences between client/server and peer-to-peernetworks. Remember that a file and print serveror an application server can be part of either aclient/server or peer-to-peer network. Keep in mind that this chapter presents thebig picture—a 50,000-foot overview ofnetworking—while at the same time introducingbasic terminology and definitions that need tobe memorized.

05.919-x CH01.i68/28/98 11:26 AMC h a p t er 1Page 6NE TWO R KI NG TE R M S AND CONCEPTSINTRODUCTIONAs one of the required exams in the Microsoft MCSE certificationprogram, the exam for Networking Essentials challenges your knowledge of computer networking components, theory, and implementation. This chapter is generic in the sense that it is not specific to anyone software or hardware vendor; instead, it introduces you to someof the basic and rudimentary terms and concepts used when discussing networking. Real-world examples are provided wheneverpossible. Study this chapter carefully; you will use these terms andconcepts throughout the rest of this book and in the real world, nomatter which networking model or system is being discussed.Although most of this chapter’s examples are given in terms ofMicrosoft solutions, all other successful networking models mustaccomplish these same tasks.This chapter begins with a definition of networking. It then moveson to cover three different computing models used by various systems throughout the world. The discussion next turns to the twomain types of network models and then covers how networks areclassified based on various factors. The chapter goes on to describethe various services that a network can offer.In general, this chapter helps the reader understand some of thebroad classifications into which networks can fall. An appropriateanalogy might be motor vehicle classification—you should think interms of car, truck, or bus instead of a detailed description such as a1969 Ford Mustang or a 1998 Honda Accord.The integration of network services within personal desktop operating systems and the public emergence of the worldwide network,also known as the Internet, have generated incredible momentum inthe movement to get connected. Networks have become the primarymeans of disseminating information in most modern offices andeven in some homes.

05.919-x CH01.i8/28/98 11:26 AMPage 7C hapter 1NETWORKING CONCEPTSCOMPONENTSNETWORKING TERMS AND CONC E PT S7ANDNetworking is the concept of sharing resources and services. A network of computers is a group of interconnected systems sharingresources and interacting using a shared communications link (seeFigure 1.1). A network, therefore, is a set of interconnected systemswith something to share. The shared resource can be data, a printer,a fax modem, or a service such as a database or an email system. Theindividual systems must be connected through a pathway (called thetransmission medium) that is used to transmit the resource or servicebetween the computers. All systems on the pathway must follow aset of common communication rules for data to arrive at its intended destination and for the sending and receiving systems to understand each other. The rules governing computer communication arecalled protocols.In summary, all networks must have the following:á A resource to share (resource)á A pathway to transfer data (transmission medium)á A set of rules governing how to communicate (protocols)ABHi, BHi, AFIGURE 1.1In its simplest form, a computer network is twoor more computers sharing information acrossa common transmission medium.

05.919-x CH01.i88/28/98 11:26 AMC h a p t er 1Page 8NE TWO R KI NG TE R M S AND CONCEPTSHaving a transmission pathway does not always guarantee communication. When two entities communicate, they do not merelyexchange information; rather, they must understand the informationthey receive from each other. The goal of computer networking,therefore, is not simply to exchange data but to understand and usedata received from other entities on the network.An analogy is people speaking (see Figure 1.2). Just because two people can speak, it does not mean they automatically can understandeach other. These two people might speak different languages orinterpret words differently. One person might use sign language,while the other uses spoken language. As in human communication,even though you have two entities who “speak,” there is no guarantee they will be able to understand each other. Just because two computers are sharing resources, it does not necessarily mean they cancommunicate.Because computers can be used in different ways and can be locatedat different distances from each other, enabling computers to communicate often can be a daunting task that draws on a wide varietyof technologies.Student(client)FIGURE 1.2Human communication is like a network.Air(transmissionmedium)Instructor(server)

05.919-x CH01.i8/28/98 11:26 AMPage 9C hapter 1NETWORKING TERMS AND CONC E PT SThe two main reasons for using computer networking are to provideservices and to reduce equipment costs. Networks enable computersto share their resources by offering services to other computers andusers on a network. The following are specific reasons for networking PCs:á Sharing filesá Sharing printers and other devicesá Enabling centralized administration and security of theresources within the systemá Supporting network applications such as electronic mail anddatabase servicesYou will learn more about these important network functions laterin this chapter.MODELSOFNETWORK COMPUTINGAfter you have the necessary prerequisites for network communication, a structure must be put in place that organizes how communication and sharing occurs. Three methods of organization, ormodels, generally are recognized. The following are the three modelsfor network computing:á Centralized computingá Distributed computingá Collaborative or cooperative computingThese three models are the basis for the various types of computernetworks you learn about in this book. The following sections discuss the three models for network computing.Centralized ComputingThe first computers were large, expensive, and difficult to manage.Originally, these large mainframe computers were not networked asyou are familiar with today. Jobs were entered into the system byreading commands from card decks. The computer executed one job9

05.919-x CH01.i108/28/98 11:26 AMC h a p te r 1Page 10NE TWO R KI NG TE R MS AND CONCEPTSat a time and generated a printout when the job was complete.Terminals, which came later, provided the user with a new mechanism to interact with the centralized computer. These terminals,however, were merely input/output devices that had no independentprocessing power. All processing still took place on the central mainframe, (see Figure 1.3) hence the name centralized computing.Networks, therefore, served little purpose other than to deliver commands to and get results from the powerful centralized processingdevice. To this day, large mainframe systems are still being operatedaround the world, most often by governments and large corporations. An example of centralized computing to which everyone canrelate is using an ATM machine. ATMs function as terminals. Allprocessing is done on the mainframe computer to which the ATMsare connected. In summary, the centralized computing modelinvolves the following:á All processing takes place in the central mainframe computer.á Terminals are connected to the central computer and functiononly as input/output devices.This early computing model worked well in large organizations thatcould justify the need for these expensive computing devices. One of100% of computingNo computingMainframeDumbterminalNo computingNo computingPrinterDumbterminalFIGURE 1.3In centralized computing all the processing isdone by a central computer.

8/28/98 11:26 AMPage 11C hapter 1NETWORKING TERMS AND CONCE PT Sthe drawbacks, however, was that the mainframes were not flexiblein their placement (some were the size of a large room) and did notscale down to meet the needs of smaller organizations. New ways ofsharing information were necessary to allow computing power to beshared efficiently on smaller networks.Distributed ComputingAs personal computers (PCs) were introduced to organizations, anew model of distributed computing emerged. Instead of concentrating computing at a central device, PCs made it possible to give eachworker an independent, individual computer. Each PC could receiveinput and could process information locally, without the aid ofanother computer (see Figure 1.4).NOTE05.919-x CH01.iPersonal Computer Terminology.The term PC initially referred to a specific device—the IBM PC computer.Over time, PC has become a genericterm referring to any desktop computer. Some purists, however, still usethe term PC to refer to an IBMcompatible workstation computerand use the term Mac to refer to acomputer from Apple.This meant that groups who previously had found the cost of amainframe environment to be prohibitive were now able to gain thebenefits of computing at a far lower cost than that of a mainframe.These PCs, however, did not have the computing power of a mainframe. Thus, in most instances, a company’s mainframe could not bereplaced by a PC.An analogy might help clarify the difference between the two computing models. A mainframe, which uses a centralized computingmodel, is like a bus. A bus is a large, powerful vehicle used to transport many people at once. Everyone goes to one location—thebus—to be transported. In the same way, everyone must work70% of the processing30% of the processingInformation flowsFIGURE 1.4Distributed computing.11