Networking Components and Devices

Networking Components and Devices

Objectives

This chapter covers the following CompTIA-specified objectives for the "Media and Topologies" and "Protocols and Standards" sections of the Network+ exam:

Identify the purpose, features, and functions of the following network components:

·         Hubs

·         Switches

·         Bridges

·         Routers

·         Gateways

·         CSU/DSU

·         Network interface cards (NICs), ISDN adapters, and system area network cards

·         Wireless access points (WAPs)

·         Modems

A wide range of devices are used in modern networking. As a Network+ certified technician, you will need to have a good understanding of commonly used devices.

Given an example, identify a Media Access Control (MAC) address.

MAC addresses are the means by which systems communicate at a base level. As a network administrator, you will need to understand the purpose, function, and expression of MAC addresses.

Outline

·         Introduction

·         Hubs

·         Switches 

·         Switching Methods

·         Working with Hubs and Switches 

·         Hub and Switch Ports

·         Cables Connecting Hubs and Switches

·         Hub and Switch Indicator Lights

·         Rack Mount, Stackable, and Freestanding Devices

·         Managed Hubs and Switches

·         Bridges 

·         Bridge Implementation Considerations

·         Types of Bridges

·         Routers 

·         Routable Protocols and Routing Protocols

·         Routable Protocols

·         Routing Protocols

·         Dedicated Hardware Versus Server-Based Routers

·         Gateways

·         CSUs/DSUs

·         Wireless Access Point (WAPs)

·         Modems 

·         Modem Connection Speeds

·         Network Cards (NICs) 

·         Types of Network Interfaces

·         Installing Network Cards

·         ISDN Terminal Adapters

·         System Area Network Cards 

·         Network Devices Summary

·         Identifying MAC Addresses

·         Chapter Summary

·         Apply Your Knowledge

Study Strategies

·         Read the objectives at the beginning of the chapter.

·         Study the information in this chapter, paying special attention to the tables, which summarize key information.

·         Review the objectives again.

·         Answer the exam questions at the end of the chapter and check your results.

·         Use the ExamGear test on the CD-ROM that accompanies this book to answer additional exam questions concerning this material.

·         Review the notes, tips, and exam tips in this chapter. Make sure you understand the information in the exam tips. If you don't understand the topic referenced in an exam tip, refer to the information in the chapter text and then read the exam tip again.

Introduction

So far this book has examined topologies, media access methods, networking standards, and cable types and connectors. To complete our examination of networking on a physical level, this chapter looks at the network devices that are used to create networks.

·         Identify the purpose, features, and functions of the following network components:

·         Hubs

·         Switches

·         Bridges

·         Routers

·         Gateways

·         CSU/DSU

·         Network interface cards (NICs), ISDN adapters, and system area network cards

·         Wireless access points (WAPs)

·         Modems

Each of these devices fulfills a specific role in a network; however, only the largest and most complex environments use all of them. We'll begin our discussion of networking devices with perhaps the most simple and common network device used today: the hub.

Repeaters

Traditionally, any discussion of networking components would include repeaters, but today repeaters are a little outdated. Repeaters were once used to increase the usable length of the cable, and they were most commonly associated with co-axial network configurations. Because coaxial networks have now fallen out of favor, and because the functionality of repeaters has been built in to other devices, such as hubs and switches, repeaters are rarely used. For this reason, CompTIA has elected to leave them out of the required knowledge for the Network+ exam.

Basic computer network components

Computer networks share common devices, functions, and features including servers, clients, transmission media, shared data, shared printers and other hardware and software resources, network interface card(NIC), local operating system(LOS), and the network operating system (NOS).

Servers - Servers are computers that hold shared files, programs, and the network operating system. Servers provide access to network resources to all the users of the network. There are many different kinds of servers, and one server can provide several functions. For example, there are file servers, print servers, mail servers, communication servers, database servers, fax servers and web servers, to name a few.

Clients - Clients are computers that access and use the network and shared network resources. Client computers are basically the customers(users) of the network, as they request and receive services from the servers.

Transmission Media - Transmission media are the facilities used to interconnect computers in a network, such as twisted-pair wire, coaxial cable, and optical fiber cable. Transmission media are sometimes called channels, links or lines.

Shared data - Shared data are data that file servers provide to clients such as data files, printer access programs and e-mail.

Shared printers and other peripherals - Shared printers and peripherals are hardware resources provided to the users of the network by servers. Resources provided include data files, printers, software, or any other items used by clients on the network.

Network Interface Card - Each computer in a network has a special expansion card called a network interface card (NIC). The NIC prepares(formats) and sends data, receives data, and controls data flow between the computer and the network. On the transmit side, the NIC passes frames of data on to the physical layer, which transmits the data to the physical link. On the receiver's side, the NIC processes bits received from the physical layer and processes the message based on its contents.

Local Operating System - A local operating system allows personal computers to access files, print to a local printer, and have and use one or more disk and CD drives that are located on the computer. Examples are MS-DOS, Unix, Linux, Windows 2000, Windows 98, Windows XP etc.

Network Operating System - The network operating system is a program that runs on computers and servers, and allows the computers to communicate over the network.

Hub - Hub is a device that splits a network connection into multiple computers. It is like a distribution center. When a computer requests information from a network or a specific computer, it sends the request to the hub through a cable. The hub will receive the request and transmit it to the entire network. Each computer in the network should then figure out whether the broadcast data is for them or not.

Switch - Switch is a telecommunication device grouped as one of computer network components. Switch is like a Hub but built in with advanced features. It uses physical device addresses in each incoming messages so that it can deliver the message to the right destination or port.

Like a hub, switch doesn't broadcast the received message to entire network, rather before sending it checks to which system or port should the message be sent. In other words, switch connects the source and destination directly which increases the speed of the network. Both switch and hub have common features: Multiple RJ-45 ports, power supply and connection lights.