In This Chapter
* Understanding network hardware and software
* Recognizing a network's anatomy
* Making sure that the network's running
* Sharing resources
* Following Windows networking trends into the new millennium
If you've ever used a cell phone or watched a TV show, you've used a network, perhaps without even realizing it. Much of the world's modern communications infrastructure, including wired and wireless telephones, cable and broadcast TV, and the Internet, depends on networks.
Windows Server 2003 needs a network, too. Because servers exist to provide file, print, directory, Web, security, and other services to clients across a network, using Windows Server 2003 without a network is like using a telephone that's not plugged into the wall. Although that phone may have some value as abstract art, its real value comes from its capability to connect you with other people or services. The same is true for Windows Server 2003.
In this chapter, we introduce you to the various components that make up a Windows Server 2003-based network and briefly discuss how each one works.
What's This about a Network?
A network requires at least two computers linked in a way that enables them to talk to each other. Most networks use electrical wires of some type to convey signals and data between computers. However, numerous types of networking media, including wireless technologies and fiber-optic cables, also support networked connections. In other words, you can get from here to there in many ways on modern networks!
A network's key ingredients always include some type of physical connection that allows computers to talk (and listen) to some kind of communications medium. Even if that network medium is wireless, something must physically connect computers to an antenna or to a similar device that allows those computers to broadcast and receive signals.
But there's more to networking than hardware. Although cables and connections are essential, they are purely decorative and can serve no useful purpose without software. In the following sections, you find out a bit more about the hardware and software that make networks work.
No hardware means no connections!
First and foremost, networking requires working connections to enable computers to communicate with each other. Networking hardware creates connections between computers and a network and defines the medium (or media) that allows information to flow from sender to receiver.
Networking hardware covers a broad range of devices, many of which you may find on your networks. In the first part of this book, we help you understand the roles and functions these devices play on a network.
From the most basic perspective, computers need the following hardware to talk to each other on a typical network:
Without software, networks don't work
Software lets computers access and use hardware, whether that hardware is used for networking-related functions or for other purposes.
By now, you should understand that hardware provides the necessary connections that make networking possible, and software supports the communications and services needed to access the hardware and the network to which the hardware is attached.
Many different types of software play a supporting role when networking modern computers. This software includes special-purpose programs called device drivers, which allow a computer to address a network interface and exchange data with that interface. The software collection also includes full-blown applications that can access data on a local computer or on a server across the network with equal aplomb. The software also includes a bunch of other stuff that sits between device drivers and applications.
Throughout this book, we show you how to recognize the various pieces of software involved in networking and how to best configure that software to work with Windows Server 2003 on a network.
Investigating Your Network's Facilities
If you tour an average network, you can't help but discover that many different types of equipment and a variety of related software are in use. If you inventory all the components in a network, you can use that data to figure out what's attached to your network and what functions various devices perform on your network.
The infrastructure that makes networking possible is made up of the equipment that hooks computers into a network, the cables or other networking media that ferry information between computers, and the hardware and software used to create and control a network. You may also call the collection of connections, cables, interfaces, and other equipment glue because these elements bind computers into a working network.
Workstations for everyone!
One of networking's primary advantages is that a network takes what you do at your desk - and we bet you usually call it "work" - and lets you do what you do more efficiently by allowing you to interact with remote resources and data. This means you can access a file on a server as if it's part of your own disk drive, send a job to a printer elsewhere on the network as if it were hooked directly to your machine, and so on. Sharing resources remains the most highly touted benefit of networking because it connects your desktop computer to file stores, printers, applications, and information resources that would otherwise be inaccessible or too expensive to add to every desktop computer.
The terms network client, desktop computer, and workstation are all used more or less synonymously in the networking world. No matter what you call them, these machines are where users do the bulk of their work (and perhaps some play at odd moments).
A desktop is also the area of a computer that displays the program icons and the wallpaper.
One of the key goals that drives networking is to interconnect all the desktops in an organization, whether they run a DOS, Windows, UNIX, Linux, or Macintosh operating system, so that they can communicate and share resources. Some of the resources shared by workstations include large disk arrays, expensive color or laser printers, CD-ROM jukeboxes, and high-speed Internet connections (all of which would be too expensive to connect to every desktop machine).
On most networks, the ratio of desktop machines to users is pretty close to one-to-one. In other words, each user has access to a workstation attached to the network, even if that user is not the only person who works on that machine. Because workstations are where requests for services originate, such machines are known as network clients, or more simply, as clients.
When you call such a machine a workstation, you emphasize its capability to support an individual user more or less independently. When you call such a machine a client, you focus on its connection to the network. Whatever you call it, it's a machine that sits on your desk and is connected to a network.
A server is always at your service
Networking is about obtaining access to shared services. Because networks are useless unless you can do something with them, access to services is what networking is all about.
On modern networks, servers provide the capabilities necessary to obtain access to resources or to do things. For example, when you send a print job to a networked printer, you can assume that, somewhere in the background, a print server is handling the job. Likewise, when you request a file from a network drive, a file server is probably involved. When you poke around in the network directory - you guessed it! - a directory server is pulling the strings. For every service, some type of server handles and responds to requests. Sometimes, a single server provides many services; at other times, a server provides only a single service.
Computers that provide services to clients are generically called servers. A server's job is to listen for requests from clients for whatever service or services it offers, and to satisfy any valid requests for its services. In fact, validating service requests is an important part of what servers do - you wouldn't want just anyone to be able to print the salaries for everyone in your company just because a user asks a print server to do so. You want that server to verify that Bob is allowed to access that file before you let him print it! Throughout this book, you find out more about such validations and other key aspects of what it takes for a server to provide services.
The common path of networking
A common pathway must exist between any computer that requests services and any computer whose job it is to satisfy such requests. Just as you need a highway to drive from one city to another, you need a pathway over which your computer can send and receive data. On a network, that's the job of the media that tie all the various pieces together.
Look around and observe the types of cables and connections used on your network. Get a sense of the structure of your network so you can tell which highways the users use - from the side roads that only the folks in the accounting or shipping department use to the main road that all users use.
When you observe how all the pieces fit together - workstations, servers, and media - you get a reasonably complete view of your network. Figure 1-1 depicts a simple network diagram that shows these purely physical elements of a network. Notice that clients (desktop machines) outnumber servers, and that media tie all the pieces together. Networking follows the law of supply and demand, so the more clients you have, the more (or bigger) servers you'll need - and the more work will get accomplished!
What Is the Sound of a Working Network?
Figuring out whether a network is functioning is both easy and hard, and most observers, including novices and experts alike, agree that telling when a network's not working is easier than telling when it is! A client must know how to ask for services from the network and must state precisely what it's requesting. Likewise, a server must know how to recognize and evaluate incoming requests for its services and how to respond appropriately. Only then can a network work correctly.
Understanding how this constant stream of requests and replies works means looking a little deeper into how clients state their requests and how servers satisfy them. In the following sections, we examine the mechanics of this give-and-take.
Knowing how to ask is where the game begins
Knowing how to ask for network services requires some ability to distinguish between what's available locally on a client machine and what's available remotely from the network. Determining what's local and what's remote is the key to handling network access correctly. This determination depends on specialized software to handle the job in the background, so users don't necessarily have to know the difference.
A computer's main control program is called its operating system (OS) because it defines the software environment that lets a computer operate and run the applications and system services that get things accomplished on a machine. Most modern operating systems include built-in networking capabilities to augment their control over local resources and devices.
Certain modern operating systems can be called network operating systems (NOSs) when they create network server environments. Their built-in networking capabilities include a range of network services as part and parcel of the underlying operating system. Windows Server 2003 certainly fits this bill because it offers a broad range of powerful, flexible networking capabilities.
Right out of the box, Windows Server 2003 understands the differences between local and remote resources. The same is true for most modern desktop operating systems, including Windows XP Professional, Windows 2000 Server and Professional, Windows NT Server and Workstation, Windows 9x, the Macintosh OS, as well as that old (but still modern) warhorse, UNIX.
In Windows Server 2003, Windows XP Professional, Windows 2000, Windows NT, Windows 9x, Macintosh, and UNIX operating systems, and through add-ons to DOS and Windows 3.x, a special piece of software known as a redirector keeps track of what's local and what's remote when users or applications request resources. The redirector takes generic requests for services and sends any that can't be satisfied locally to the appropriate service provider elsewhere on the network (in other words, to the appropriate server). Therefore, if you ask for a file that resides on a server elsewhere on the network, the redirector hands your request off to that machine and makes sure that the results of that request are delivered properly.
What's on today's menu?
For a computer to use network services, the computer must know how to ask for them. That's what a requester does. But knowing what to ask for is as important as knowing how to ask. In most cases, applications supply the necessary information about network services that they want to access, either through information supplied from a requester or through knowledge built directly into an application itself.
E-mail clients and Web browsers represent good examples of applications with sophisticated, built-in networking capabilities. On the other hand, file system access tools, such as Windows Explorer, My Computer, and My Documents, rely on the redirector to furnish them with views of (and access to) shared files and printers elsewhere on the network.
Please note that applications with built-in networking knowledge offer transparent access to network services because the applications know how to ask for services and, often, what to ask for on the user's behalf. Programmers design such computer applications to be transparent to keep the applications out of sight and out of mind; therefore, the user remains blissfully unaware of cumbersome networking details and trivia. File managers, printer controls, and other tools with access to both local and remote resources, however, require users to be able to tell the difference between what's local and what's remote. In fact, such tools usually force users to request access to remote resources explicitly and directly.
Excerpted from Windows Server 2003 For Dummies by Ed Tittel James Michael Stewart Copyright © 2002 by Ed Tittel. Excerpted by permission.
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