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
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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
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