Network Concepts


A revolution is going on now, and it compares to the one Johannes Gutenberg started in 1456 when he pioneered the use of movable type. The ability to print in quantity made it possible for the first time for the common man to gain knowledge by himself. This new revolution is based on global connectivity, and its impact is on our ability to disseminate information by ourselves. We now take it for granted that we can share information, preach, publish, talk, and touch the rest of the world through our computers. Networks have radically changed the way the world communicates.

Networks aren't limited to just the work environment anymore. Many homes with a computer quickly end up with two or more, and it's not long before it seems sensible to tie them together with a network. So, whether or not you have one now, a network is probably in your future. In this chapter, you'll learn how networking works and how Windows XP provides the tools to help you become part of the connected world.

NOTE

This chapter is designed to provide some basic networking concepts. If you have been networking computers for some time, feel free to skip ahead. If you are new to networking, read on. This chapter will help get you pointed in the right direction.


Why You Really Need a Network

I probably don't have to convince you of the value of tying your computers together with a network, even if you have only two. With a network, you can do the following:

  • Use any printer attached to any computer.

  • Share files, that is, get at files stored on one computer from another. At home, having this capability might mean you can finish that letter you were writing yesterday using your kids' computer because they're now using yours to manage their stock portfolios. In the office, a network lets workers share information quickly and facilitates the creation of a centralized documentation system.

  • Share CD-ROMs.

  • Back up networked computers with one common backup systemfor example, a tape drive.

  • Use network-enabled application software, such as databases, workgroup scheduling and calendar programs, and email. Network-enabled software is designed to give multiple users simultaneous access to information that is updated in real-time.

  • Share a single Internet connection among several computers, saving on telephone lines and connection costs.

  • Play multi-user games within your home or office, or across the Internet.

A network can justify its cost with printer or Internet connection sharing alone. But how hard is it to put together?

No Longer a Dark Art

It doesn't seem possible that it's now nearly 15 years since I installed my first network in a client's office. It was a nerve-wracking experience because it had cost my client thousands of dollars in hardware and software above the cost of the computers alone, and although he didn't know, I had never installed networking software or a file server before. Networking was reputed to be a costly, mystical, and dark art, and I soon found that this reputation was well-deserved. The network eventually worked. For several thousand dollars, my client got 10 computers that could read and write to the same database file.

Now a network card can cost half the price of a movie ticket, you can buy network cables at the corner hardware store, and first-class networking software is, well, nearly freeit's free if you were going to buy Windows anyway. And you can probably take it for granted that you should be able to just plug and play.

In the next few chapters, you'll learn how to use Windows networking to connect to the computer in your basement, to the rest of your office workgroup, or to a worldwide corporate enterprise. You may still need to learn an incantation or two, but fear not, they're no longer in Latin.

One other point: I'll be using the word resource frequently in this chapter. By resource, I mean a shared folder or printer on someone else's computer, which you can access through the LAN.

Network Neighborhoods

Windows XP has, right out of the box, all the software you need to communicate and share information with other computers. Windows XP Professional can fill several roles, depending on the way it's connected to other computers. It can be any of the following:

  • A standalone computer working in complete isolation. An example might be a simple home computer.

  • A standalone computer connected to others via a modem. An example is a laptop computer with a modem used to connect to an office or to the Internet. This computer works in isolation some of the time but can socialize when needed. You can think of this type as a remote workstation.

  • A member of a small workgroup of computers with no central "server." An example might be a computer in a small office or home office, one of say 2 to 10. The computers share resources with each other but are essentially independent. This computer is a peer in what is called a peer-to-peer network; no one computer has an intrinsically special role in making the network work. All the participants are on equal footing; they are peers. Not all the computers need to use Windows XP either; Windows XP can peer with older versions of Windows and other operating systems such as Mac OS and Linux.

  • A member of a group of computers working under the stewardship of a central server. This computer is probably one of a group of a dozen or more. The designated master computer or server contains, at least, centralized username and password information, which it passes out as a service to the other computers on the network. These other computers are the clients in a client/server network. Windows XP Professional can be the client of a server run by Windows Server 2003, Windows 2000 Server, or Novell NetWare.

  • A member of a client/server network that is in turn connected to other networks. An example is a computer in a branch office of a large company. This computer is participating in an enterprise network, where special consideration has to be made to management, security, and the allocation of resources of many, many computers and people spread out over a wide geographical area.

Windows XP Professional has all the stuff to participate in any of these network environments. The one thing it can't do is take the central, or server, role of a client/server or enterprise network. The reason for this is that Windows XP Pro doesn't have the ability to act as a centralized user/password database. For that, you need at least one computer running one of the Windows Server versions or one of its more upscale varieties: Advanced Server, Enterprise Server, or Data Center.

NOTE

Microsoft cleverly named the successor to Windows 2000 Server "Windows Server 2003." Why they had to move the number around, we don't know. But, to keep things simpler in our text, we're going to use the name "Windows 200x Server" when our discussion doesn't have to make a distinction between the two.


Windows XP Professional file sharing service can make a network connection with at most 10 other computers. If you need to share a network resource (such a printer or file folder) with more than 10 computers, you'll need one of the Windows Server versions.

In the next few chapters, you'll learn how to configure and tune up Windows XP in each of these environments. If you already understand how networks work, you can skip ahead to "The Many Faces of Windows XP" later in this chapter. If not, check out the following sections for an introduction to the concepts and terms you should know.

Network Form and Function

What makes a network tick? Let's start by looking at Figure 15.1, the first sort of network you probably built.

Figure 15.1. Did your first network look like this?


Don't laugh! A tin can telephone has many of the attributes of a computer network. The basis of a network is a physical transport medium: a means of carrying raw information (for example, words) over a medium (string) between hardware interfaces (cans). When you first used a tin can phone, you found out right away that you couldn't speak at the same time as the person on the other end, so you had to work out a protocol to coordinate your conversation: You probably said "over" after you spoke, like the astronauts and pilots you saw in the movies. Finally, you found that there's a limit to how long the string could be for the phone to work. If the string was too long, you couldn't hear.

Computer networks have these components and limitations, too. The raw information in a network is digital data (bits), carried over a physical medium (usually wires or optical fibers, but sometimes radio waves) between hardware interfaces (network adapters plugged into your computer), according to a mutually agreed-upon protocol that coordinates the computers' conversations.

Size Matters

A computer network is often called a local area network, or LAN. A LAN is a group of computers connected by a physical medium that supports a relatively high rate of data transmission, say 1 million bits per second (Mbps) or more, in relatively close proximity, say within one building, all able to communicate directly with each other. (Imagine 10 cans on strings, all tied together in the center!) Most home and small office LANs transmit data at 10 or 100Mbps (million bits per second). This is fast enough that loading and saving large word processing documents to a remote computer isn't noticeably slower than using your own hard drive. Hot-rod networks can run as fast as 1000Mbps. This kind of blazing speed is used mostly in corporate settings and by digital-media mavens.

The electrical nature of LAN communication limits the physical distance allowed between computers to at most a few hundred yards. LANs can be extended much farther using optical fiber cables, which carry data as pulses of light, to connect groups of computers sharing a more traditional (and inexpensive) electrical connection. You might hear this arrangement called a campus network or metropolitan area network.

A wide area network, or WAN, is a group of two or more LANs tied together over even longer distances. Historically, these connections were much slower, between 56 thousand bits per second (Kbps) and 1Mbps because long-distance connections were extremely expensive. (A 56Kbps connection between San Francisco and Chicago with a guaranteed throughput of only 16Kbps cost about $2,500 per month in 1996.) Now that the telecommunications companies have installed optical fiber cables all over the world, even WAN connections can be as fast as LAN connections these days. Using the Internet, a 400Kbps connection between any two points in the U.S. can be made for as little as $300 per month.

In addition to your data, LANs carry quite a bit of "chatter" as the member computers broadcast questions, asking for the location of needed resources, and as servers broadcast announcements of the services they provide. This communications overhead could use up most of the carrying capacity of a slow WAN connection, so special devices called routers examine and make decisions about what data to send back and forth between the disparate geographical areas.

As I mentioned earlier, one of the main distinctions of a server-based network is a centralized username/password database. To let users continue working if the long-distance connection fails, and to provide speedier logon checks, builders of WAN networks usually install a server at each geographic location. Windows 200x Server lets administrators add or alter user information at any one location, and the server automatically copies the changes to all the other servers. For large enterprises, this one feature alone makes it worth the extra bucks.



Special Edition Using Microsoft Windows XP Professional
Special Edition Using Microsoft Windows XP Professional (3rd Edition)
ISBN: 0789732807
EAN: 2147483647
Year: 2003
Pages: 450

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