Ethernet Networking for the Small Office and Professional Home Office

Jan L. Harrington

• Publisher: Morgan Kaufmann
• Year: 2010
• ISBN:
  9780080553603
• Topic: Computer Science
• Subtopic: Computer Networking
• Index: Computer Science

In a local area network (LAN) or intranet, there are many pieces of hardare trying to gain access to the network transmission media at the same time (i.e., phone lines, coax, wireless, etc.). However, a network cable or wireless transmission frequency can physically only allow one node to use it at a given time. Therefore, there must be some way to regulate which node has control of the medium (a media access control, or MAC, protocol). Ethernet is a MAC protocol; it is one way to regulate physical access to network tranmission media.

Ethernet networking is used primarily by networks that are contained within a single physical location. If you need to design, install, and manage a network in such an envronment, i.e., home or small business office, then Ethernet Networking for the Small Office and Professional Home Office will give you an in-depth understanding of the technology involved in an Ethernet network.

One of the major goals of this book is to demystify the jargon of networks so that the reader gains a working familiarity with common networking terminology and acronyms.

In addition, this books explains not only how to choose and configure network hardware but also provides practical information about the types of network devices and software needed to make it all work. Tips and direction on how to manage an Ethernet network are also provided.

This book therefore goes beyond the hardware aspects of Ethernet to look at the entire network from bottom to top, along with enough technical detail to enable the reader to make intelligent choices about what types of transmission media are used and the way in which the various parts of the network are interconnected.

• Explains how the Ethernet works, with emphasis on current technologies and emerging trends in gigabit and fast Ethernet, WiFi, routers, and security issues
• Teaches how to design and select complementary components of Ethernet networks with a focus on home and small business applications
• Discuses the various types of cables, software, and hardware involved in constructing, connecting, operating and monitoring Ethernet networks

Part One

Introduction

Introduction to Introduction

The first two chapters of this book present some introductory conceptual material about networking and Ethernet. By the time you finish reading them, you will understand exactly what Ethernet is and the part it plays in your network.

1

Introduction

One of the biggest problems when discussing networking is knowing where to start. The subject of computer networks is one of those areas for which you have to “know everything to do anything.” Usually, the easiest way to ease into the topic is to begin with some basic networking terminology and then look at exactly what it means when we use the word Ethernet.

Anatomy of a Network

A computer network is a combination of hardware and software that allows computers and other devices (for example, printers and file servers) to communicate with one another through some form of telecommunications media (for example, telephone lines).

Note: As you read material about data communications, you may see references to POTS lines. POTS stands for “plain old telephone service.”

Networks can be classified by the distances they cover and whether they include technology like that used on the Internet:

LAN (local area network): A network confined to a small geographic area–such as a floor, single building, or group of buildings in close physical proximity (for example, a college campus or an office park)–that is almost always owned by a single organization. The organization owns the telecommunications lines as well as the hardware connected to the network.

Intranet: A network (LAN or WAN) owned by a single company that uses technology similar to that used on the Internet.

MAN (metropolitan area network): An outdated term describing a network that covers an entire city. Today, the concept of a MAN has been replaced largely by the WAN.

WAN (wide area network): A network that covers a large geographic area, such as a city, state, or one or more countries. Although a WAN may be owned by a single organization, the network usually includes telecommunications media (for example, telephone lines or satellite transmissions) that are leased from commercial telecommunications providers.

Internet: When in all lowercase letters (internet), a WAN that connects multiple networks into a larger network. When written with a leading uppercase letter (Internet), it is the global network that supports the World Wide Web. Because of the potential for confusion between internet and Internet, the term internet is rarely used today.

The technologies we will be discussing in this book are applicable to LANs and intranets. Although we will discuss connecting LANs to the Internet, the focus is on creating and maintaining networks that serve small to medium-size workgroups in small offices, regardless of whether they are located in commercial buildings or homes.

Network Components

A computer network is made up of three major components:

Hardware: The equipment that connects to the network. Typically, this includes computers, printers, and modems. Each distinct piece of hardware on a network is known as a node. In addition to the hardware that actually uses the network to transfer data to perform work for an organization, a network may contain specialty hardware that helps manage the network and connects it to other networks. Such hardware includes routers, bridges, switches, hubs, repeaters, and gateways. You will read about network hardware of these types throughout this book.

Each device on a network is identified by two types of addresses. The first is a hardware address that physically identifies the piece of equipment. In many cases, this address is set by the hardware manufacturer and is not easily changed. These addresses, known as MAC (media access control) addresses, must be unique throughout the network segment. If a manufacturer happens to produce hardware with duplicated MAC addresses, then a network segment that uses that hardware cannot function.

The second type of address is a software address that is added by the software that handles data transmission. The software address can be changed as needed.

Software: The programs that manage the transfer of data throughout the network, most commonly known as network operating systems (NOS). Current desktop operating systems—Windows, Mac OS X, and Linux—are capable of network operations right out of the box. However, they cannot provide the robust, centralized, shared services such as file sharing needed by commercial networks. Most organizations therefore end up investing in specialized network operating system software to provide services such as file sharing, user management, security, and directory management.

Transmission media: The cables or wireless signals that carry data from one node to another.

In addition, there must be interfaces between the hardware and the network. These often take the form of expansion boards that are added to pieces of hardware (network interface cards, or NICs, such as that in Figure 1-1), although a significant number of today’s computers and printers are shipped with network hardware already installed on their motherboards. Depending on the type of transmissions media in use, a network may also need hardware connections between the media coming from a piece of hardware and the network itself.

Figure 1-1 A network interface card (Courtesy of Farallon Corp.)

In Figure 1-2 you can see a generalized diagram of how the hardware fits together. Each device you want to connect to a network must have either a network interface card or networking hardware installed on its motherboard. The NIC (or the motherboard) contains a port to which a cable can be attached. That cable runs to the network, connecting to the network tra...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Preface
• Part One: Introduction
• Part Two: Design and Connectivity
• Part Three: Making the Network Work
• Part Four: Ethernet Solution Examples
• A: Older Ethernet Standards
• B: TCP and UDP Ports
• C: Products and Vendors
• Glossary
• Index