Introduction Who Should Read This Book? To the computer semi-literate, the administrator is “the source.” He is the person who knows everything that there is to know about computers and networking. LAN adminis- trators like this reputation and, where novice users are concerned, it is not difficult to maintain. As more and more people begin to see computing as a way of life, however, the knowledge required for the administrator to maintain her reputation for omnipo- tence is increasing at a rapid rate. That’s where this book comes in. It may just be a casual question from a user, regarding something that he saw on his monitor, like “What does IPX stand for, anyway?” It may be a practical complaint, like “Why can’t I print from my Macintosh to the laser printer near my desk, rather than walking all the way over to Marketing, where the Apple printers are?” Given the way in which computing and the Internet has invaded the mainstream media, it may be a guy from Sales, who has a computer at home, stopping by your office, sticking his head in the door and saying, “Hey, what’s the difference between a SLIP and a PPP connection?” Or, worst of all, it may be your boss, telling you that “I want us to be on the Internet by the end of the month.” Whatever the case, there is going to be, at some point, something that you don’t know or that you can’t handle, and when it comes to networking, this book is designed to be the first place for the LAN administrator to go for information. Product manuals give you the “How?” This book is about the “What?” and the “Why?” For instructions on how to install a stand-alone printer on your network, you go to a product manual. You have already made the decisions as to what kind of printer to buy and what kind of network connection you are going to use. This book is designed to help you in making those decisions. Its value comes earlier in the process, when you are asking the most basic questions, like “How can I provide printing services to the greatest number of different clients, with the fewest administration headaches, for the least amount of money?” What Are the Main Objectives of This Book? You may be the new LAN Administrator at a company, faced with a lot of equipment with which you are unfamiliar. This book can help you get up to speed. You may be working for a growing company that wants to expand its computing services around the office, around the building, the country, or the world. This book is the first step, telling Introduction you what is involved in a certain procedure, providing you with information that will be useful in talking to salespeople and evaluating products and pointing you in the right direction for the next step in the process. This is the age of the heterogeneous network. Computers and LANs that may have been installed as separate systems are now being interconnected to provide uniform access to hardware and information resources and to simplify administration and maintenance. A company may be in the process of phasing out their mainframe systems and replacing them with LANs. In the interim, however, the two will have to be connected. The ben- efits of connecting a company’s remote offices and traveling personnel to a central information source are now widely recognized, and the technology has been developed to make this practice logistically and economically feasible. The vast resources of the Internet are rapidly becoming a fixture, not only in offices but in private homes as well. It is very likely that, within five to ten years, Internet connections will be as common as telephones and televisions. To the non-technical corporate management, a LAN administrator is expected to know something about all of these things. Telecommunications, cable installation, electrical engineering, systems analysis, project management, and technical training are just some of the disciplines involved. We’ve come a long way from the time when a person could learn how to use DOS, take a few NetWare courses, and hang out her shingle as a net- work administrator. Unfortunately, in most companies, management has little concep- tion of the true breadth of knowledge required to cover all of these divergent needs. A typical network administrator may know a great deal about some of these disciplines, a little about all of them, or even nothing about any of them, in some cases. For every practitioner, in every profession, there are elements of his field about which he is expected to know but doesn’t. Most are aware of it, and some are even smug about it (I once met a Professor of English Literature who admitted to having never read Hamlet!). The LAN administrator is no different, and the savvy ones are those who have arrived at the point when faced with a subject that they have heard of and should be familiar with, but aren’t, will nod their heads knowingly, promise to look into the situation, and then read up on it at the next opportunity. This is the book that they should turn to first. Will it tell them absolutely everything that they need to know? Of course not. A single work that covered every aspect of modern computer networking would be the size of the Encyclopedia Britannica and would have to be revised at least once a week. The field is growing and developing at an incredibly rapid rate, and a network administrator must continuously expand and update his knowledge in order to remain current. That is why great pains have been taken in this book to cover the latest developments in the net- working industry. You will find information on a great many of the new technologies that are just entering into general use or are soon to be so. We are not talking about speculative possibilities, though, but concrete products and services that exist in the real world and not just on a drawing board. What Should You Get Out of This Book? No one can predict whether or not an emerging technology will become a networking standard. That is as much a question about marketing as it is about the technology itself. Keeping current in today’s networking industry consists largely of anticipating new trends and making sensible judgments as to when (or if) it would be safe, practical, and economical to adopt them for use at your network installation. Those who judge wisely, remain employed. Those who don’t, usually end up making a big mess that must be cleaned up by the next administrator. Unfortunately, a good portion of the effort de- voted to the development of an emerging technology is expended on devising ways to convince you that this product or service is the one that you need and that, until you have it, you will never be up to speed with the industry. We hope, in this book, to sepa- rate the publicity from the facts and provide you with more of the latter than the former. What Should You Get Out of This Book? Computer networking, and indeed computing in general, is about communications. To accomplish even the simplest task using a computer, literally dozens of different forms of electronic signaling and communications are used by the various components involved. People speak of this as the digital age and of binary code as the fundamental communi- cations medium for all computers, everywhere. But how do the zeroes and ones get from one place to another? Just as you can telescope in on a video, audio, or textual format to see its binary code, you can zoom in even farther and look at how electrical currents or light pulses are used to make up the binary format. Many people know a lot about computers, but no one person knows everything about them. From the microscopic inner workings of a microprocessor to the sealed environ- ment where magnetic particles store data on the platters of a hard disk drive all the way up to the microwave and satellite technologies used to transmit data between computers located thousands or even millions of miles apart, the variety and complexity of the signaling and communications techniques involved in networking is colossal in scope. You don’t need to know how to design a microprocessor to purchase a computer. You don’t need to know how to build a space shuttle to bounce a signal off of a satellite. Indeed, you probably do both more frequently than you think, without even knowing it. But there may well be times when you want to know something about what goes on within these “transparent” systems. When you are charged with making a decision as to which processor to have in the thousand computers that your company may be purchas- ing this year, it is good to know something more about the subject than you would nor- mally get in a magazine ad or a TV commercial. That’s what this book is for. The more that you know about the inner workings of a com- puter or a network, the more sense can be made from its outside manifestations, and your troubleshooting skills become that much more acute as a result. Introduction No one is expected to sit down and read a book like this, from cover to cover. It is more likely to be used as a point of reference, a background source that examines most of the tasks that are likely to be asked of a network administrator as well as most of the technol- ogy with which he comes into daily contact.