Tài liệu MCSE Training Guide: Networking Essentials, ppt

Second Edition Networking Essentials MCSE TRAINING GUIDE Exam: 70-058 Glenn Berg 01.919-x FM 8/28/98 10:08 AM Page i I S TANDARDS AND T ERMINOLOGY 1 Networking Terms and Concepts 2 Networking Standards PART 04.919-x Part1 8/28/98 10:59 AM Page 1 O BJECTIVES 1 CHAPTER Networking Terms and Concepts Chapter 1 targets the following objectives in the Standards and Terminology section of the Networking Essentials exam: Compare a client/server network with a peer-to- peer network. . This objective makes sure you are familiar with the two main network classification models. Define common networking terms for LANs and WANs. . The purpose of this objective is to make sure peo- ple working in the networking field understand the difference between a local area network (LAN) and a wide area network (WAN). These terms are the main topics of discussion throughout this chapter. Compare a file and print server with an applica- tion server. . This objective makes sure you are aware of the dif- ferent types of servers in the field of networking. 05.919-x CH01.i 8/28/98 11:26 AM Page 3 O UTLINE Networking Concepts and Components 7 Models of Network Computing 9 Centralized Computing 9 Distributed Computing 11 Collaborative Computing 12 Network Models: Comparing Client/Server and Peer-to-Peer Networking Configurations 13 Client/Server Based Networking 13 Peer-to-Peer Networking 15 Local and Wide Area Networks 16 Local Area Networks (LANs) 16 Wide Area Networks (WANs) 16 Intranets and Internets 17 Network Services 18 Basic Connectivity Services 18 Redirector Service 19 Server Service 19 File Services 20 File Transfer Services 23 Data Migration 24 File Archiving 25 File-Update Synchronization 25 Printing Services 26 Application Services 26 Database Services 28 Messaging/Communication Services 30 Email 31 Voice Mail 31 Fax Services 31 Groupware 31 Directory Services 32 Security Services 33 Chapter Summary 36 05.919-x CH01.i 8/28/98 11:26 AM Page 4 S TUDY S TRATEGIES . You need to be very familiar with the terminolo- gy used throughout this chapter. This terminolo- gy serves as a basis for the rest of the book and for the exam. . Many different services are explained in this book. Be prepared to understand the key differences between a file and print server and an application server, as well as the differ- ences between client/server and peer-to-peer networks. Remember that a file and print server or an application server can be part of either a client/server or peer-to-peer network. . Keep in mind that this chapter presents the big picture—a 50,000-foot overview of networking—while at the same time introducing basic terminology and definitions that need to be memorized. 05.919-x CH01.i 8/28/98 11:26 AM Page 5 6 Chapter 1 NETWORKING TERMS AND CONCEPTS I NTRODUCTION As one of the required exams in the Microsoft MCSE certification program, the exam for Networking Essentials challenges your knowl- edge of computer networking components, theory, and implementa- tion. This chapter is generic in the sense that it is not specific to any one software or hardware vendor; instead, it introduces you to some of the basic and rudimentary terms and concepts used when dis- cussing networking. Real-world examples are provided whenever possible. Study this chapter carefully; you will use these terms and concepts throughout the rest of this book and in the real world, no matter which networking model or system is being discussed. Although most of this chapter’s examples are given in terms of Microsoft solutions, all other successful networking models must accomplish these same tasks. This chapter begins with a definition of networking. It then moves on to cover three different computing models used by various sys- tems throughout the world. The discussion next turns to the two main types of network models and then covers how networks are classified based on various factors. The chapter goes on to describe the various services that a network can offer. In general, this chapter helps the reader understand some of the broad classifications into which networks can fall. An appropriate analogy might be motor vehicle classification—you should think in terms of car, truck, or bus instead of a detailed description such as a 1969 Ford Mustang or a 1998 Honda Accord. The integration of network services within personal desktop operat- ing systems and the public emergence of the worldwide network, also known as the Internet, have generated incredible momentum in the movement to get connected. Networks have become the primary means of disseminating information in most modern offices and even in some homes. 05.919-x CH01.i 8/28/98 11:26 AM Page 6 Chapter 1 NETWORKING TERMS AND CONCEPTS 7 N ETWORKING C ONCEPTS AND C OMPONENTS Networking is the concept of sharing resources and services. A net- work of computers is a group of interconnected systems sharing resources and interacting using a shared communications link (see Figure 1.1). A network, therefore, is a set of interconnected systems with 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. The individual systems must be connected through a pathway (called the transmission medium) that is used to transmit the resource or service between the computers. All systems on the pathway must follow a set of common communication rules for data to arrive at its intend- ed destination and for the sending and receiving systems to under- stand each other. The rules governing computer communication are called 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) Hi, AHi, B BA FIGURE 1.1 In its simplest form, a computer network is two or more computers sharing information across a common transmission medium. 05.919-x CH01.i 8/28/98 11:26 AM Page 7 8 Chapter 1 NETWORKING TERMS AND CONCEPTS Having a transmission pathway does not always guarantee communi- cation. When two entities communicate, they do not merely exchange information; rather, they must understand the information they receive from each other. The goal of computer networking, therefore, is not simply to exchange data but to understand and use data received from other entities on the network. An analogy is people speaking (see Figure 1.2). Just because two peo- ple can speak, it does not mean they automatically can understand each other. These two people might speak different languages or interpret 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 guaran- tee they will be able to understand each other. Just because two com- puters are sharing resources, it does not necessarily mean they can communicate. Because computers can be used in different ways and can be located at different distances from each other, enabling computers to com- municate often can be a daunting task that draws on a wide variety of technologies. Student (client) Air (transmission medium) Instructor (server) FIGURE 1.2 Human communication is like a network. 05.919-x CH01.i 8/28/98 11:26 AM Page 8 Chapter 1 NETWORKING TERMS AND CONCEPTS 9 The two main reasons for using computer networking are to provide services and to reduce equipment costs. Networks enable computers to share their resources by offering services to other computers and users on a network. The following are specific reasons for network- ing PCs: á Sharing files á Sharing printers and other devices á Enabling centralized administration and security of the resources within the system á Supporting network applications such as electronic mail and database services You will learn more about these important network functions later in this chapter. M ODELS OF N ETWORK C OMPUTING After you have the necessary prerequisites for network communi- cation, a structure must be put in place that organizes how commu- nication and sharing occurs. Three methods of organization, or models, generally are recognized. The following are the three models for network computing: á Centralized computing á Distributed computing á Collaborative or cooperative computing These three models are the basis for the various types of computer networks you learn about in this book. The following sections dis- cuss the three models for network computing. Centralized Computing The first computers were large, expensive, and difficult to manage. Originally, these large mainframe computers were not networked as you are familiar with today. Jobs were entered into the system by reading commands from card decks. The computer executed one job 05.919-x CH01.i 8/28/98 11:26 AM Page 9 10 Chapter 1 NETWORKING TERMS AND CONCEPTS at a time and generated a printout when the job was complete. Terminals, which came later, provided the user with a new mecha- nism to interact with the centralized computer. These terminals, however, were merely input/output devices that had no independent processing power. All processing still took place on the central main- frame, (see Figure 1.3) hence the name centralized computing. Networks, therefore, served little purpose other than to deliver com- mands to and get results from the powerful centralized processing device. To this day, large mainframe systems are still being operated around the world, most often by governments and large corpora- tions. An example of centralized computing to which everyone can relate is using an ATM machine. ATMs function as terminals. All processing is done on the mainframe computer to which the ATMs are connected. In summary, the centralized computing model involves the following: á All processing takes place in the central mainframe computer. á Terminals are connected to the central computer and function only as input/output devices. This early computing model worked well in large organizations that could justify the need for these expensive computing devices. One of 100% of computing No computing Dumbterminal No computing No computing Printer Mainframe Dumbterminal FIGURE 1.3 In centralized computing all the processing is done by a central computer. 05.919-x CH01.i 8/28/98 11:26 AM Page 10 [...]... PEER-TO-PEER NETWORKING CONFIGURATIONS Compare a client/server network with a peer-to-peer network Networks generally fall into one of two broad network categories: á Client/server networks á Peer-to-peer networks It is important to remember that one type of networking configuration is not necessarily better than another Each type of networking model has its own strengths and weaknesses Client/Server-Based Networking. .. peer-to-peer networking for two reasons The first reason is a desire to network with their current stock 05.919-x CH01.i 8/28/98 11:26 AM Page 23 C hapter 1 NETWORKING TERMS AND CONCE PT S of PCs without the expense of a centralized server Another reason is that a peer-to-peer network is an informal networking approach that fits the working style of many organizations Microsoft implements peer-to-peer networking. .. that facilitate networking Some of these components are discussed in other chapters, and some are beyond the scope of the Networking Essentials exam (You’ll learn about them when you study for the Windows NT Server or Windows NT Workstation exam.) This section introduces you to a pair of key network services—the redirector service and the server service—that are at the core of all networking functions... network must have special system software that enables them to function in a networking environment The first network operating systems really were add-on packages that supplied the networking software for existing operating systems such as MS-DOS or OS/2 More recent operating systems, such as Windows 95 and Windows NT, come with the networking components built in An analogy might help you differentiate fully... terms commonly used in computer networking It also has addressed many of the basic networking structures you need to understand as an administrator In doing so, this chapter has provided a general framework you can use when analyzing a network in terms of its general design and the function it is trying to serve or perform In this chapter, the exam objective “Define common networking terms for LANs and... application, the directory service tells the client where the resource is on the network and whether the resource is available (see Figure 1.12) This is a service that more and more networking systems are moving towards As networking systems have developed, they have begun to include this feature This is similar to a large company having an information desk, whereas a small company probably would not... client/server model is a network in which the role of the client is to issue requests and the role of the server is to service requests 05.919-x CH01.i 8/28/98 11:26 AM Page 15 C hapter 1 NETWORKING TERMS AND CONCE PT S Peer-to-Peer Networking A peer-to-peer network consists of a group of PCs that operate as equals Each PC is called a peer The peers share resources (such as files and printers) just like in a...8/28/98 11:26 AM Page 11 C hapter 1 NETWORKING TERMS AND CONCE PT S the drawbacks, however, was that the mainframes were not flexible in their placement (some were the size of a large room) and did not scale down to meet the needs of smaller... move goods The box and the mechanism for transportation (the chassis) are integrated from the beginning; they are designed to operate with each other 05.919-x CH01.i 8/28/98 11:26 AM Page 19 C hapter 1 NETWORKING TERMS AND CONCE PT S 19 Client and server machines require specific software components A computer that is strictly a server often cannot provide any client functionality On a Novell server or... For both of these products, requests originate from intelligent client software (which uses the processor power of the workstation it is running on) 05.919-x CH01.i 8/28/98 11:26 AM Page 13 C hapter 1 NETWORKING TERMS AND CONCE PT S but then are serviced from server software running on a Windows NT server The server then processes the request using its own resources and passes the results back to the . Edition Networking Essentials MCSE TRAINING GUIDE Exam: 70-058 Glenn Berg 01.919-x FM 8/28/98 10:08 AM Page i I S TANDARDS AND T ERMINOLOGY 1 Networking. Comparing Client/Server and Peer-to-Peer Networking Configurations 13 Client/Server Based Networking 13 Peer-to-Peer Networking 15 Local and Wide Area Networks