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

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

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

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

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

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

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

Computers Networks and Networking Networks 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 Networks 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 Networks 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