Setting Up and Accessing a Small Network : Understanding Networking

You’ll learn all the necessary network nomenclature (such as the difference between client/server and peer-to-peer), hardware requirements, the ins and outs of cabling, protocol descriptions, and lots more. You can think of this section as your initiation into the black art of networking, except, as you’ll see, things aren’t as black as they used to be.

If you just have a single computer in your office or at home, and if you’re the only person who uses that computer, your setup is inherently efficient. You can use the machine whenever you like, and everything you need—your applications, your printer, your CD-ROM drive, your modem, and so on—will be readily available.

Things become noticeably less efficient if you have to share the computer with other people. Then you might have to wait for someone else to finish a task before you can get your own work done; you might need to have separate applications for each person’s requirements; and you might need to set up separate folders to hold each person’s data. Windows XP’s user accounts and Fast User Switching features ease these problems, but they don’t eliminate them. However, although this solution might ease some of the burden, it won’t eliminate it entirely. For example, you might still have to twiddle a thumb or two while waiting for another person to complete his work.

A better solution is to increase the number of computers available. Now that machines with fast processors, ample RAM, and massive hard disk space can be had for less than $1,000, a multiple-machine setup is an affordable proposition for small offices. Even at home, the current trend is to buy a nice system for mom and dad to put in their office, while the kids inherit the old machine for their games and homework assignments.

Multiple machines, however, bring with them new inefficiencies:

• In many cases, it’s just not economically feasible to supply each computer with its own complete set of peripherals. Printers, for example, are a crucial part of the computing equation—when you need them. If someone needs a printer only a couple of times a week, it’s hard to justify shelling out hundreds of dollars so that person can have his or her own printer. The problem, then, is how to share a printer (or whatever) among several machines.

• These days, few people work in splendid isolation. Rather, the norm is that colleagues and coworkers often have to share data and work together on the same files. If everyone uses a separate computer, how are they supposed to share files?

• Most offices have standardized on particular software packages for word processing, spreadsheets, graphics, and other mainstream applications. Does this mean that you have to purchase a copy of an expensive software program or suite for each machine? As with peripherals, what do you do about a person who uses a program only sporadically?

• Everyone wants on the Internet, of course, but paying a subscription for each user seems wasteful. What’s needed is a way to share a single Internet connection.

Yes, you can overcome these limitations. To share a printer, for example, you could simply lug it from machine to machine, as needed, or else get a 100-foot parallel cable that can be plugged into whichever computer needs access to the printer. This won’t work if you need to share an internal CD-ROM drive, however. For data, there’s always the old “sneaker net” solution: Plop the files on a floppy disk and run them back and forth between computers. As for applications, you could install some programs on a single machine and require users to share, but that brings us back to the original problem of multiple people sharing a single machine.

There has to be a better way. For example, wouldn’t it be better if you could simply attach a peripheral to a single machine and make it possible for any other computer to access that peripheral whenever it is needed? Wouldn’t it be better if users could easily move documents back and forth between computers, or had a common storage area for shared files? Wouldn’t it be better if you installed an application in only one location and everyone could run the program on his own machine at will?

Well, I’m happy to report that there is a better way, and it’s called networking. The underlying idea of a network is simple: You connect multiple machines by running special cables from one computer to another. These cables plug into adapter cards (called network interface cards; I’ll talk more about them later in this chapter) that are installed inside each computer. With this basic card/cable combination—or even a wireless setup—and a network-aware operating system (such as Windows XP), you can solve all the inefficiencies just described:

• A printer (or just about any peripheral) that’s attached to one machine can be used by any other machine on the network.

• Files can be transferred along the cables from one computer to another.

• Users can access disk drives and folders on network computers as though they were part of their own computer. In particular, you can set up a folder to store common data files, and each user will be able to access these files from the comfort of her machine. (For security, you can restrict access to certain folders and drives.)

• You can install an application on one machine and set things up so that other machines can run the application without having to install the entire program on their local hard drive. There’s no such thing as a free lunch, however. You have to purchase a license to install the application on the other computers. However, depending on how many users you have, buying a license is usually cheaper than buying additional full-blown copies of the application.

• You can set up an Internet connection on one machine and share that connection with other machines on the network.

Not only are the problems solved, but a whole new world of connected computing becomes available. For example, you can establish an email system so that users can send messages to each other via the network. You can use groupware applications that enable users to collaborate on projects, schedules, and documents. As the administrator of the network, you can remotely manage other computers, such as installing new software or customizing the environment for each user.

It sounds great, but are there downsides to all of this? Yes. Unfortunately, there is no such thing as a networking nirvana just yet. In all, you have three main concerns:

The benefits of connectivity, however, greatly outweigh the disadvantages, so budding network administrators shouldn’t be dissuaded by these few quibbles. Now that I’ve convinced you that a network is a good thing, let’s turn our attention to the types of networks you can set up.

LANs, WANs, MANs, and More

Networks come in three basic flavors: local area networks, internetworks, and wide area networks:

Other types of networks also exist. A campus network connects all the buildings in a school campus or an industrial park. Such networks often span large geographical areas, like WANs, but use private cabling to connect their subnetworks. A metropolitan area network (MAN) connects computers in a city or county and is usually regulated by a municipal or state utility commission. Finally, an enterprise network connects all the computers within an organization, no matter how geographically diverse the computers might be, and no matter what kinds of operating systems and network protocols are used in individual segments of the network.

Client/Server Versus Peer-to-Peer

It used to be that the dominant network model revolved around a single, monolithic computer with massive amounts of storage space and processing power. Attached to this behemoth were many dumb terminals—essentially just a keyboard and monitor—that contained no local storage and no processing power. Instead, the central mainframe or minicomputer was used for all data storage and to run all applications.

The advent of the PC, however, has more or less sounded the death knell for the dumb terminal. Not surprisingly, users prefer having local disks so that they can keep their data close at hand and run their own applications. (This is, after all, the personal computer we’re talking about.) To accommodate the PC revolution, two new kinds of network models have become dominant: client/server and peer-to-peer.

Client/Server Networks

In general, the client/server model splits the computing workload into two separate, yet related, areas. On one hand, you have users working at intelligent front-end systems called clients. In turn, these client machines interact with powerful back-end systems called servers. The basic idea is that the clients have enough processing power to perform tasks on their own, but they rely on the servers to provide them with specialized resources or services, or access to information that would be impractical to implement on a client (such as a large database).

This client/server relationship forms the basis of many network operating systems. In this case, a server computer provides various network-related services, such as access to resources (a network printer, for example), centralized file storage, password verification and other security measures, server-based application setup, email, data backups, and access to external networks (such as the Internet).

The various client PCs, although they have their own storage and processing power, interact with the server whenever they need access to network-related resources or services, as illustrated in Figure 1. Client computers are also referred to as nodes or workstations.

Note that in most client/server networks, the server computer can perform only server duties. In other words, you can’t use it as a client to run applications.

In this client/server networking model, two types of software are required:

For small LANs, a single server is usually sufficient for handling all client requests. As the LAN grows, however, the load on the server increases and network performance can suffer. Nothing in the client/server model restricts a network to a single server, however. So, to ease the server burden, most large LANs utilize multiple servers. In distributed networks, administrators are free to organize the servers’ duties in any way that maximizes network performance. For example, administrators can split clients into workgroups and assign each group to a specific server. Similarly, they can split the duties performed by each server. For example, one server could handle file services, whereas another could handle print services, and so on.

Peer-to-Peer Networks

In a peer-to-peer network, no computer is singled out to provide special services. Instead, all the computers attached to the network have equal status (at least as far as the network is concerned), and all the computers can act as both servers and clients, as illustrated in Figure 2.

On the server side, each computer can share any of its resources with the network and control access to these shared resources. For example, if a user shares a folder with the network, she also can set up passwords to restrict access to that folder.

On the client side, each computer can work with the resources that have been shared by the other peers on the network (assuming that it has permission to do so, of course).

Which One Should You Choose?

If you’re thinking about networking a few computers, should you go with a client/server setup or a peer-to-peer model? That’s a tough question to answer because it depends on so many factors: the number of computers you want to connect, the operating system (or systems) you’re using, the services you need, the amount of money you have available to spend, and so on.

In general, the smaller the network, the more sense the peer-to-peer model makes. This is particularly true if you’re running Windows XP because it’s designed as a peer-to-peer NOS. After you’ve installed your network cards and run your cables, you’re more or less ready to go. Windows XP’s automatic hardware detection usually does a pretty good job of recognizing and configuring the network hardware, and the network client makes it easy to share and access network resources.

If, rather than just a few computers, you have a few dozen, you’ll have to go the client/server route. Large peer-to-peer setups are just too unwieldy to maintain and administer, and performance quickly drops off as you add more nodes. A top-of-the-line client/server NOS (such as Windows 2003 Server or NetWare) comes with remote administration, scales nicely as you add more clients and servers, and is robust enough to handle large loads. The price you pay for all this power is, well, the price: These big-time operating systems are expensive and usually require an extra hardware investment beyond the standard card/cable combo. And with power comes complexity. Unlike the relative simplicity of their peer-to-peer counterparts, administration of medium-to-large client/server networks isn’t for the faint of heart.