ComputersNetworks and Networking

The Data Communications ChannelWireless communication

Microwave signal – sent from one transmitter to anotherRadio frequency (RF) signal – line-of-sight

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ComputersNetworks and Networking

The Data Communications ChannelCommunications satellite – repeater for microwave transmissions in geosynchronous orbitGeosynchronous orbit – 22,300 miles above the earth

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ComputersNetworks and Networking

The Data Communications ChannelWireless networks

Access points – college campuses, coffee shops, local area networks

Wi-Fi – approximately 300 foot rangeBluetooth – approximately 30 foot range

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ComputersNetworks and Networking

The Data Communications ChannelWireless Application Protocol (WAP)

Internet access standard for wireless devices such as cell phones

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ComputersNetworks and Networking

The Data Communications ChannelFuture of wireless

Multichannel Multipoint Distribution Service (MMDS)Local Multipoint Distribution Service (LMDS)

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ComputersNetworks and Networking

The Data Communications ChannelCommon carriers

Examples: AT&T, Sprint, MCIPrivate line (leased line) – charge based on channel capacity and distanceSwitched line (dialup line) – time and distance charge

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ComputersNetworks and Networking

The Data Communications ChannelCommunications protocols – rules established to govern the way data are transmitted in a computer network Asynchronous transmission – data sent on an as-needed basisSynchronous transmission – source and destination operate in timed synchronization

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ComputersNetworks and Networking

NetworksNode – terminal, PC, or any device connected to a network

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ComputersNetworks and Networking

NetworksTypes of Networks

Personal Area Network (PAN) – connects cell phones or other electronics to the networkLocal Area Network (LAN) – nodes are in close proximity

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ComputersNetworks and Networking

NetworksTypes of Networks

Metropolitan Area Network (MAN) – network that encompasses a cityWide Area Network (WAN) – nodes of the network are geographically distant

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ComputersNetworks and Networking

NetworksLAN resources that can be shared

Applications software Links to other LANs Communications capabilities I/O devices Storage devices Add-on boards

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ComputersNetworks and Networking

NetworksLAN access methods

Network Access Method – rule that a network uses to determine priorities

Logical topology

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ComputersNetworks and Networking

NetworksEthernet – widely used network access method; uses Carrier Sense Multiple Access/Collision Detection (CSMA/CD protocol)Token Access Method

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ComputersNetworks and Networking

NetworksServers

File server – stores programs and data to be shared via the networkPrint server – handles print jobsCommunication server – provides access to other networksLAN server – PC designed to be server

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ComputersNetworks and Networking

NetworksLAN software

Network operating system (NOS)Peer-to-peer (P2P)Dedicated server

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ComputersNetworks and Networking

NetworksLAN software

Peer-to-peer LAN – all PCs are equal in the networkClient/server LAN – NOS resides on the server computer

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ComputersNetworks and Networking

NetworksApplication software for LANs

Client/server LAN applications softwareFront-end application software – user interface and applications software processed locally Back-end application software – handles tasks associated with storage and maintenance of databases

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ComputersNetworks and Networking

NetworksApplication software for LANs

Download (server-to-client)Upload (client-to-server)

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ComputersNetworks and Networking

NetworksShared applications software

Groupware – allows a group of people to work on a project

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ComputersNetworks and Networking

NetworksShared applications software

Electronic mail (e-mail)Instant messagingCalendar and schedulingBrainstormingShared whiteboarding

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ComputersNetworks and Networking

NetworksShared applications software

Setting prioritiesElectronic conferencingElectronic forms

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ComputersNetworks and Networking

NetworksHome network – small LAN in the home

© 2005 Prentice-Hall, Inc. Slide 47

ComputersNetworks and Networking

NetworksHome network technologies

WiredWirelessHome phoneline networking (HomePNA or HPNA) – uses existing telephone lines to create the networkHomePlug – uses electrical lines to connect computers in the network

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ComputersNetworks and Networking

NetworksHome 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?

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ComputersNetworks and Networking

NetworksSteps to installing a home network

Install network interface cardsSet up communication hardwareLink PCs to router/hub/switchSet up network softwareIdentify files/printers to be sharedSet up Internet connection sharing

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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