Computers © 2005 Prentice-Hall, Inc. Slide 1

Chapter 6 Networks and Networking Computers Chapter 6 Networks and Networking © 2005 Prentice-Hall, Inc. Slide 2

Computers Chapter 6 – Networks and Networking Objectives Apply the concept of connectivity to your life Understand data communications hardware Identify data transmissions services Understand the various network topologies Recognize the potential of home networking © 2005 Prentice-Hall, Inc. Slide 3

Computers Networks and Networking Our Wired World Connectivity – the degree to which software, hardware, and databases are functionally linked © 2005 Prentice-Hall, Inc. Slide 4

Computers Networks and Networking Our Wired World Cooperative processing Intracompany networking – cooperation within the company Intercompany networking – cooperation with other companies and customers © 2005 Prentice-Hall, Inc. Slide 5

Computers Networks and Networking Our Wired World Intranet –internal network based on Internet technology Extranet – an extension of an intranet, partially available to customers and suppliers © 2005 Prentice-Hall, Inc. Slide 6

Computers Networks and Networking Our Wired World Virtual Private Network (VPN) – network transmissions are tunneled through the Internet Tunneling – one network uses another to send data © 2005 Prentice-Hall, Inc. Slide 7

Computers Networks and Networking Data Communications Hardware Data communications or telecommunications – distribution of data © 2005 Prentice-Hall, Inc. Slide 8

Computers Networks and Networking Data Communications Hardware Server computers – central computers that control the network Client computers – computers, linked to a server, that create the network © 2005 Prentice-Hall, Inc. Slide 9

Computers Networks and Networking Data Communications Hardware Proxy server computers – handle some requests, hand others to the actual server computers © 2005 Prentice-Hall, Inc. Slide 10

Computers Networks and Networking Data Communications Hardware Telephone-link modem – converts analog signals to digital and digital signals to analog Analog – voice communication, such as over a telephone line Digital – 1’s and 0’s used to represent data in a computer © 2005 Prentice-Hall, Inc. Slide 11

Computers Networks and Networking Data Communications Hardware Modem Internal External Voice/data/fax modem © 2005 Prentice-Hall, Inc. Slide 12

Computers Networks and Networking Data Communications Hardware Cable modem – provides Internet access via cable television lines DSL (Digital Subscriber Line) – Internet access via special line provided by a telephone company Satellite modem – Internet access via communications satellite © 2005 Prentice-Hall, Inc. Slide 13

Computers Networks and Networking Data Communications Hardware Network interface card (NIC) – also called network card and network adapter Needed to connect a personal computer to a network Ethernet – de facto standard © 2005 Prentice-Hall, Inc. Slide 14

Computers Networks and Networking Data Communications Hardware Gateway – allows for communication between networks using different protocols Router – routes messages to the appropriate destination Gateway router – both functions in one device © 2005 Prentice-Hall, Inc. Slide 15

Computers Networks and Networking Data Communications Hardware Message Source – device that sends the message Destination – device that receives the message Handshaking – router establishes the connection between the source and the destination © 2005 Prentice-Hall, Inc. Slide 16

Computers Networks and Networking Data Communications Hardware Network address – assigned to each computer on a network; used to send messages to the appropriate destination Backbone – the routers, gateways, and other equipment that link the computers of the network © 2005 Prentice-Hall, Inc. Slide 17

Computers Networks and Networking Data Communications Hardware Hub – expands the number of nodes on a network Half-duplex – data can only be sent in one direction at a time Switch – acts like a hub for a local area network (LAN) Full-duplex – data can be sent in both directions at once © 2005 Prentice-Hall, Inc. Slide 18

Computers Networks and Networking Data Communications Hardware Terminals Video Display Terminal – input/output device Thin client – smart terminal, capable of some processing © 2005 Prentice-Hall, Inc. Slide 19

Computers Networks and Networking Data Communications Hardware Telephony – integration of telephones and computers © 2005 Prentice-Hall, Inc. Slide 20

Computers Networks and Networking Data Communications Hardware Automatic Teller Machine (ATM) – used in banking Point-of-Sale (POS) terminals – used in retail © 2005 Prentice-Hall, Inc. Slide 21

Computers Networks and Networking The Data Communications Channel Communications channel – media a message must pass through on a network Line Link Pipe © 2005 Prentice-Hall, Inc. Slide 22

Computers Networks and Networking The Data Communications Channel Transmission media Measured in bits per second (bps) © 2005 Prentice-Hall, Inc. Slide 23

Computers Networks and Networking The Data Communications Channel Twisted-pair wire POTS (plain old telephone services) Digital Subscriber Line (DSL) Cat5 cabling – uses four twisted pairs of wire; speeds of up to 100 M bps Cat5e cabling – speeds of up to 1 G bps © 2005 Prentice-Hall, Inc. Slide 24

Computers Networks and Networking The Data Communications Channel Coaxial cable – high capacity channel, capable of speeds up to 10 M bps Fiber optic cable – carries data as electrical signals © 2005 Prentice-Hall, Inc. Slide 25

Computers Networks and Networking The Data Communications Channel Wireless communication Microwave signal – sent from one transmitter to another Radio frequency (RF) signal – line-of-sight © 2005 Prentice-Hall, Inc. Slide 26

Computers Networks and Networking The Data Communications Channel Communications satellite – repeater for microwave transmissions in geosynchronous orbit Geosynchronous orbit – 22,300 miles above the earth © 2005 Prentice-Hall, Inc. Slide 27

Computers Networks and Networking The Data Communications Channel Wireless networks Access points – college campuses, coffee shops, local area networks Wi-Fi – approximately 300 foot range Bluetooth – approximately 30 foot range © 2005 Prentice-Hall, Inc. Slide 28

Computers Networks and Networking The Data Communications Channel Wireless Application Protocol (WAP) Internet access standard for wireless devices such as cell phones © 2005 Prentice-Hall, Inc. Slide 29

Computers Networks and Networking The Data Communications Channel Future of wireless Multichannel Multipoint Distribution Service (MMDS) Local Multipoint Distribution Service (LMDS) © 2005 Prentice-Hall, Inc. Slide 30

Computers Networks and Networking The Data Communications Channel Common carriers Examples: AT&T, Sprint, MCI Private line (leased line) – charge based on channel capacity and distance Switched line (dialup line) – time and distance charge © 2005 Prentice-Hall, Inc. Slide 31

Computers Networks and Networking The Data Communications Channel Communications protocols – rules established to govern the way data are transmitted in a computer network Asynchronous transmission – data sent on an as-needed basis Synchronous transmission – source and destination operate in timed synchronization © 2005 Prentice-Hall, Inc. Slide 32

Computers Networks and Networking Node – terminal, PC, or any device connected to a network © 2005 Prentice-Hall, Inc. Slide 33

Computers Networks and Networking Types of Networks Personal Area Network (PAN) – connects cell phones or other electronics to the network Local Area Network (LAN) – nodes are in close proximity © 2005 Prentice-Hall, Inc. Slide 34

Computers Networks and Networking Types of Networks Metropolitan Area Network (MAN) – network that encompasses a city Wide Area Network (WAN) – nodes of the network are geographically distant © 2005 Prentice-Hall, Inc. Slide 35

Computers Networks and Networking LAN resources that can be shared Applications software Links to other LANs Communications capabilities I/O devices Storage devices Add-on boards © 2005 Prentice-Hall, Inc. Slide 36

Computers Networks and Networking LAN access methods Network Access Method – rule that a network uses to determine priorities Logical topology © 2005 Prentice-Hall, Inc. Slide 37

Computers Networks and Networking Ethernet – widely used network access method; uses Carrier Sense Multiple Access/Collision Detection (CSMA/CD protocol) Token Access Method © 2005 Prentice-Hall, Inc. Slide 38

Computers Networks and Networking Servers File server – stores programs and data to be shared via the network Print server – handles print jobs Communication server – provides access to other networks LAN server – PC designed to be server © 2005 Prentice-Hall, Inc. Slide 39

Computers Networks and Networking LAN software Network operating system (NOS) Peer-to-peer (P2P) Dedicated server © 2005 Prentice-Hall, Inc. Slide 40

Computers Networks and Networking LAN software Peer-to-peer LAN – all PCs are equal in the network Client/server LAN – NOS resides on the server computer © 2005 Prentice-Hall, Inc. Slide 41

Computers Networks and Networking Application software for LANs Client/server LAN applications software Front-end application software – user interface and applications software processed locally Back-end application software – handles tasks associated with storage and maintenance of databases © 2005 Prentice-Hall, Inc. Slide 42

Computers Networks and Networking Application software for LANs Download (server-to-client) Upload (client-to-server) © 2005 Prentice-Hall, Inc. Slide 43

Computers Networks and Networking Shared applications software Groupware – allows a group of people to work on a project © 2005 Prentice-Hall, Inc. Slide 44

Computers Networks and Networking Shared applications software Electronic mail (e-mail) Instant messaging Calendar and scheduling Brainstorming Shared whiteboarding © 2005 Prentice-Hall, Inc. Slide 45

Computers Networks and Networking Shared applications software Setting priorities Electronic conferencing Electronic forms © 2005 Prentice-Hall, Inc. Slide 46

Computers Networks and Networking Home network – small LAN in the home © 2005 Prentice-Hall, Inc. Slide 47

Computers Networks and Networking Home network technologies Wired Wireless Home phoneline networking (HomePNA or HPNA) – uses existing telephone lines to create the network HomePlug – uses electrical lines to connect computers in the network © 2005 Prentice-Hall, Inc. Slide 48

Computers Networks and Networking Home network decisions How many computers? Where will they be placed? How much do you want to spend? What is your networking expertise? Do you expect the network to grow? What applications do you want to run? © 2005 Prentice-Hall, Inc. Slide 49

Computers Networks and Networking Steps to installing a home network Install network interface cards Set up communication hardware Link PCs to router/hub/switch Set up network software Identify files/printers to be shared Set up Internet connection sharing © 2005 Prentice-Hall, Inc. Slide 50

Computers Chapter 6 – Networks and Networking Lesson Summary Apply the concept of connectivity to your life Understand data communications hardware Identify data transmission services Understand the various network topologies Recognize the potential of home networking © 2005 Prentice-Hall, Inc. Slide 51