The Nuts and Bolts of Networks How Can You Use Networks to Your Advantage? Chapter 7

©2003 The McGraw-Hill Companies Student Learning Outcomes 1.Identify and describe the four basic components of networks 2.Describe what you need to set up a small peer-to-peer network at home 3.Identify how you would wirelessly access a wired network 4.Define client/server networks and what differentiates them from peer-to-peer

©2003 The McGraw-Hill Companies Student Learning Outcomes 5.Describe the three segments of a cellular phone system 6.Explain the function of each of the three segments of a global positioning system 7.Define the five types of communications media used in business networks

©2003 The McGraw-Hill Companies Introduction Networks play a prominent role in our lives, and enable us to communicating effectively. Computer network – a collection of computers that support the sharing of information, software, and hardware devices.

©2003 The McGraw-Hill Companies 7.1 Networks: The Big Picture The term “network” can mean a few computers that are connected, or it can mean literally thousands of computers tied together The largest network on the planet is the Internet with millions and millions of computers

©2003 The McGraw-Hill Companies Common Characteristics of all Networks Network cards Connecting devices Network operating system software Communications media

©2003 The McGraw-Hill Companies Network Principles Network card in each computer to act as a doorway for information to move in and out One or more connecting devices to connect the computers together and to pass messages between them i.e., Hub Cable to provide a pathway for information to move around on or wireless devices that propel information through the air A network operating system to move information in and out of the computer

©2003 The McGraw-Hill Companies Network Hardware & Software NIC Cable and connector Hub Network Operating System  SimNet Concepts Support CD: “Connectivity Concepts” and “What Is a Network”

©2003 The McGraw-Hill Companies Advantages: Home Network Share files to avoid keeping multiple copies on different computers Share hardware among several computers Share broadband Internet connections Transfer information between computer devices

©2003 The McGraw-Hill Companies Network Definitions Local area network (LAN) is a network in the same building, complex, or small geographic area Peer-to-peer network simplest kind of network in which all computers are equal, and each can have access to devices and files on the others

©2003 The McGraw-Hill Companies Network Definitions Client/server network a network in which one or more computers are servers and provide services to the other computers

©2003 The McGraw-Hill Companies Wired Home Networks Peer-to-peer network –Network where a few computers share hardware and information –All computers are equal, and each can have access to devices and files on the others –Each computer independently stores its own software and information, but can access the information on the other computers –All computers can access devices connected to any of the other computers  SimNet Concepts Support CD: “Peer-to-Peer Systems”

©2003 The McGraw-Hill Companies Peer-to-Peer Network Components Network Interface Card Connecting Device Network Operating System Pathways for Information

©2003 The McGraw-Hill Companies Ethernet Cards Ethernet card is the most common type of NIC. Three forms of Ethernet cards are: Integrated card (on Motherboard) Expansion CardPC Card

©2003 The McGraw-Hill Companies Network Hubs Network hub is a device that connects computers into a network, broadcasting all messages it gets to every computer on the network, although only the intended recipient computer takes the message Computers that are not the recipients of the message simply ignore it Hubs can only handle one-way information traffic at a time

©2003 The McGraw-Hill Companies Network Switches Switch is a device that connects computers into a network and, unlike a hub, sends messages only to the computer that is the intended recipient Switches can handle multiple communications channels at the same time Switch can temporarily segment parts of the network with high traffic from the rest of the network

©2003 The McGraw-Hill Companies Network Home Routers Home router is a device that connects computers into a network, and also connects dissimilar networks together, separating the network traffic and keeping local traffic inside its own network Home router can handle multiple communications channels Home router keeps local traffic inside your home network

©2003 The McGraw-Hill Companies Wired Communications Media Cat 5 cable with RJ-45 connectors on each end is the most common type of cable used in home networks Similar to ordinary phone cable, but more robust One RJ-45 connector plugs into the router, and the other into the Ethernet Card RJ-45 Connectors

©2003 The McGraw-Hill Companies Popular Network Operating System Software Windows (Windows 95 and newer) Netware Linux

©2003 The McGraw-Hill Companies Wireless Network Access IrDA Uses red light (infrared) below what your eye can see Bluetooth Uses radio waves up to 30 feet WiFi Uses radio waves Up to about 300 feet

©2003 The McGraw-Hill Companies Wireless Network Access Point A WAP is a device that allows computers to access a network using radio waves A WAP has a transmitter and a receiver for bi- directional flow of information It has an antenna that radiates radio waves through the air and captures incoming waves p Fig. 7.7

©2003 The McGraw-Hill Companies Completely Wireless Network To set up a home wireless network all you actually need is to: –Install a wireless network card into each desktop computer –Ensure that all wireless devices are within, at most, 300 feet of each other  SimNet Concepts Support CD: “Wireless Communications”

©2003 The McGraw-Hill Companies Sharing an Internet Connection DSL Modem Cable Modem Satellite Modem Share broadband Internet connections

©2003 The McGraw-Hill Companies 7.3 Large Networks Client/server network is a network in which one or more computers are servers and provide services to the other computers, which are called clients Servers have hardware, software, and/or information that the client computers can access Servers are usually powerful computers with large storage systems

©2003 The McGraw-Hill CompaniesMinicomputers Mainframes High-End PCs Client/Server Computers Client/Servers can be Client/Servers can be  SimNet Concepts Support CD: “The Client/Server Relationship”

©2003 The McGraw-Hill Companies Setting up a Client/Server Network Large networks require: –Network cards –Communications media –Network operating systems on all computers in the network –At least one connecting device – a hub or switch – to tie the computers together p Fig. 7.8

©2003 The McGraw-Hill Companies Large Organizational Network p Fig. 7.9

©2003 The McGraw-Hill Companies Organizational Uses of Networks Intranet is an internal network that uses Internet technologies. Intranets generally make computer information accessible to employees and facilitate working in groups Intranet is an internal network that uses Internet technologies. Intranets generally make computer information accessible to employees and facilitate working in groups Extranet is the portion of a company’s network that allows customers or suppliers of a company to access parts of an enterprise’s intranet Extranet is the portion of a company’s network that allows customers or suppliers of a company to access parts of an enterprise’s intranet  SimNet Concepts Support CD: “Intranets and Extranets” and “Network Software and Network Administration”

©2003 The McGraw-Hill Companies Collaboration Systems Collaboration system is software that allows people to work together Any system that incorporates , chat rooms, instant messaging, and/or any other form of communications and exchange is a collaboration system Web-based collaboration tools use the power of the Internet to enable people to work together effectively and efficiently P2P collaboration system is software that enables people to communicate and share documents between peers without going through a central server

©2003 The McGraw-Hill Companies Collaboration Systems p Fig. 7.10

©2003 The McGraw-Hill Companies Two Widely Used Wireless Networks Cellular Telephone Global Positioning System

©2003 The McGraw-Hill Companies Cellular Telephone – A Form of Wireless Network Cell phones send and receive information in the form of radio waves, using a range of frequencies p Fig System identification code (SID) is a unique number that the FCC assigns a carrier Mobile telephone switching office (MTSO) stores a cell’s identification number in its database so that it can find you when calls come in for you

©2003 The McGraw-Hill Companies Global Positioning System (GPS) – Another Form of Wireless Network GPS is a navigational system that uses satellites to tell you where you are, how fast you’re going, and what direction you’re headed in p Fig. 7.12

©2003 The McGraw-Hill Companies Three Major Parts of a GPS Ground control - Five ground stations, located in different parts of the world, that monitor the system Receivers - Devices used to find out where we are Satellites - 24 satellites, each completing its own orbit every 12 hours at about 12,000 miles above the earth

©2003 The McGraw-Hill Companies 7.4 Communications Media All communications between computers are either wired or wireless Wired communications media transmit information over a closed, connected path Wireless communications media transmit information through the air

©2003 The McGraw-Hill Companies Examples of Communications Media Communications media paths, or physical channels, in a network over which information travels Optical fiber InfraredBluetooth WiFi Satellite Twisted PairMicrowave Cat 5 Cable TV

©2003 The McGraw-Hill Companies Bandwidth Bandwidth the amount of information that a communications medium can transfer in a given amount of time Capacity of communications medium is measured in bits per second (bps), thousands of bits per second (Kbps), or millions of bits per second (Mbps)  SimNet Concepts Support CD: “Bandwidth and Data Transmission”

©2003 The McGraw-Hill Companies DSL Modem 144 Kpbs = 144,000 bits per Second to 1.54 Mbps = 1,540,000 bits per second Telephone Modem 56 Kpbs = 56,000 bits per second Examples of Bandwidth Speed  SimNet Concepts Support CD: “The Client/Server Relationship”

©2003 The McGraw-Hill Companies Twisted-Pair Advantages: Varieties include Cat 5, Cat 3, and Cat 1 Relatively inexpensive and fairly easy to install and maintain. Costs of cabling is low at up to 64 kilobits per second Disadvantages: Easy to tap into and so is not very secure Possibility of distortion in information being transferred p Fig. 7.15

©2003 The McGraw-Hill Companies Optical Fiber Advantages: Fastest and most efficient medium for wired communication Cabling is very small, capacity is large, and offers greater security than with twisted-pair Attempts at tapping are easy to detect Disadvantages: Very expensive and difficult to install and maintain

©2003 The McGraw-Hill Companies Wireless Communications Media: Medium Distances Microwave communications media are line-of-sight information transmission Microwave signal cannot follow the curved surface of the earth Distances greater than 20 miles require a repeater to receive the radio signal, strengthen it, and send it on Microwave signals require a clear path from the sender to the receiver

©2003 The McGraw-Hill Companies Microwave Transmission p Fig. 7.16

©2003 The McGraw-Hill Companies Wireless Communications Media: Long Distances Communications satellites are actually microwave repeaters in space Solve the problem of line-of-sight as the transmission shoots up into the sky in a straight line and then shoots back down to earth again Stationed approximately 22,500 miles above the earth Satellite links are very expensive, and generally used by large organizations only

©2003 The McGraw-Hill Companies Communications Satellites p Fig. 7.17

©2003 The McGraw-Hill Companies

7.5 Consumer Q & A 1.Does it Matter What Type of Cable Modem I Get if I Want to Share a Broadband Internet Connection? 2.How Do I Turn On File and Device Sharing? 3.Which Cell Carries Use Which Type of Cell Networks?

©2003 The McGraw-Hill Companies 7.6 Key Terms Cat 5 cable Client/server network Collaboration system Communications media Communications satellite Computer network Ethernet card Extranet Global positioning system Home router Intranet Microwave communications media Network Interface card Network operating system Optical fiber cable Peer-to-peeer network WiFi Wired communications media Wireless communications media

©2003 The McGraw-Hill Companies Review of Concepts 1.The Eurostar Train System and Computer Networks 2.Moving Information From Here to There  If you were a song, how would you move from one computer to another?

©2003 The McGraw-Hill Companies Hands On Projects E-Commerce 1.Finding the Right Cell Phone  Wrong question: Are the local carriers as good as the national ones? 2.Buying Groceries Online  Need some potato chips for watching TV? 3.Buying and Renting Videos

©2003 The McGraw-Hill Companies Hands On Projects Ethics, Security & Privacy 1.Should Big Brother Be Allowed to Watch Us?  The British don’t mind being observed while walking around  Do you feel the same way?

©2003 The McGraw-Hill Companies Hands On Projects on the Web 1.Find Out What It Would Cost to Build Your Own Home Network 2.Investigate Satellite Radio  Listen to the same radio station while traveling from New York to L.A. 3.Find Out about Firewalls 4.Find Out what Network Terms Mean  What’s a ping?

©2003 The McGraw-Hill Companies Hands On Projects Group Activities 1.Find Out What Makes Servers Special 2.Research Your Institution’s Network 3.Investigate Which GPS Would Suit Your Needs  Garmin, Magellan, and Trimble are big 4.Try Using a Collaboration System