Explaining Networking Terms

Throughout this and any other book about networking computers, you are going to encounter network terminology.

In order for you to get the most out of the information in this book, I’m going to start by defining a few of the most common and important terms that you are going to see. I mentioned a couple of these terms in Chapter 1; now I’ll present them in more detail.

Node

Put simply, a node is a network junction or point of connection. Any device connected to a network that can send and receive data is a node. Your computer is a network node; if you have a broadband Internet router, that’s a node, too. Your access point is a node on your wireless local area network (WLAN), as is an Ethernet hub or switch.

Note 

A router is a hardware device used to interconnect networks, such as your WLAN and the Internet, and route data traffic between them. I discuss routers, and the related terms bridge and gateway, later in this chapter.

Protocol

The word protocol appears often in this book. I talk about the 802.11x protocols, TCP/IP suite protocols, and more. A protocol is a set of instructions that describes how nodes on a network communicate. Protocols determine how nodes send and receive data.

There are two types of protocol: open and proprietary. Open protocols are developed and supported by most organizations and manufacturers. Proprietary protocols are the property of one organization or company that licenses the technology to third parties.

Open protocols are usually better supported, and allow different manufacturers to produce compatible equipment at a lower cost to the consumer than is possible using proprietary technology. The main protocols discussed in this book are all open protocols.

802.11x protocols describe how Wi-Fi nodes communicate, and TCP/IP describes how nodes communicate on the Internet and other networks. Protocols allow different operating systems (Windows XP, MAC OS X, Linux, etc.) to share information and communicate by giving them a common language or way to communicate since each operating system is proprietary technology, not usually designed to interoperate with other systems.

Network

For our purposes, a network is any arrangement of interconnected nodes that can share data. There are several different physical designs or topologies of data networks (described later in this chapter). Nodes on a network share data using a shared medium (Ethernet, Wi-Fi) and a common language or protocol.

Internetwork, Internet, intranet

An internetwork is two or more connected networks or a large network comprised of smaller interconnected networks. You may be thinking, “Isn’t that what the Internet is?” Well, yes and no. There was a time when people used the terms interchangeably, and internet (not capitalized) was the abbreviated form of internetwork.

Now, Internet (capitalized) is used to refer to the global connection of networks that communicate using open protocols and standards, rather than proprietary network technologies. To refer to interconnected networks, including private networks in companies that may operate a proprietary networking technology, use the term intranet. Figure 2-1 illustrates three private networks (A, B, and C) or intranets connected with routers. Routers are devices that connect networks and route traffic between them.

Figure 2-1: Interconnected networks

This can be confusing, because you can connect an intranet to the Internet. An easy way to keep them straight is to remember that the Internet is open and public, while an intranet is private and internal. The latter is the network within your home or company, while the former is the network beyond your walls that we all share.

Host

A host is a type of node on a network that shares information and sometimes services. You can apply the name host to almost any type of network node. A client PC is a host, as is a server (see definitions below), and your PC is a host both to users and to its peripherals (printer, scanner, and so on). Because it’s applied to so many different nodes, the term host can be confusing.

Server

On a network, a server is a node that provides services (see definition below) to other nodes. A server can be a stand-alone device or computer, or it can be a client machine that shares services with other computers on the network. To confuse things, a server can also be a client when it uses services provided by another server.

The term server can refer to the machine itself as well as to individual applications that it runs (or hosts). Some server applications include Web servers, File Transfer Protocol (FTP) servers, and print servers.

Client

A client is a network node that receives services from a server. Your PC is a client; it receives service from e-mail servers, Web servers, and others. By itself, the term client implies that a device is connected to a network. Some software applications can also be clients receiving services and information from server applications.

For example, your e-mail software is an e-mail client that receives service from an e-mail server, and your Web browser is a Web client served by Web servers. A client can also act as a server for other clients by sharing resources or providing services to them.

Service

Network services are information or resources provided to clients by a server. Services include printing, messaging, e-mail, network connectivity, and Web access.

Workstation

A workstation can be one of two things. When applied to a network, a workstation is just another name for a client PC. The PC with which you connect to the network is your workstation. The term workstation can also describe a very powerful, high- end stand-alone PC. Usually workstations run some variety of Unix, and vendors of popular workstations include Sun, HP, IBM, and Silicon Graphics.

Peer

You’re probably starting to hear this term a lot, usually in reference to peer-to-peer networks, such as Kazaa. A peer is simply a node on a network that is both a server and a client to all of the other nodes on the network. Because all of the nodes are equal, they are called peers. Peer-to-peer networks are decentralized, with services being spread across all of the nodes.