Computer and Computer and Information ScienceInformation Science

Ch1.3 Ch1.3 Computer NetworkingComputer Networking Ch1.3 Ch1.3 Computer NetworkingComputer NetworkingChapter 1Chapter 1

NetworksNetworksNetworksNetworks Computer Network: series of Computer Network: series of

computers linked together to share computers linked together to share data, hardware, and softwaredata, hardware, and software

Local Area Network (LAN) : series Local Area Network (LAN) : series of computers networked together of computers networked together over a relatively limited areaover a relatively limited area– campus– building

Stand-alone computer Stand-alone computer —— a computer not a computer not connected to a network.connected to a network.

WorkstationWorkstation —— name for a computer when it name for a computer when it is connected to a network.is connected to a network.

Local resources Local resources —— workstationworkstation’’s typical s typical resources: hard drive, software, data, and resources: hard drive, software, data, and printer.printer.

Network resources Network resources —— additional resources additional resources you have access to when connected to a you have access to when connected to a network: application software, storage network: application software, storage space for data files, and shared printers.space for data files, and shared printers.

Key Network TermsKey Network TermsKey Network TermsKey Network Terms

Network server Network server —— a computer connected a computer connected to the network that distributes to the network that distributes resources to network users.resources to network users.

Network printer Network printer —— a shared printer that a shared printer that provides output capabilities to all provides output capabilities to all network users.network users.

NodeNode —— a device on a network, including a device on a network, including workstations, servers, and printers.workstations, servers, and printers.

Identifies you as a user on the Identifies you as a user on the networknetwork

Logically connects a workstation to Logically connects a workstation to network drives and other resourcesnetwork drives and other resources

Requires a user to enter a Requires a user to enter a user ID user ID and and passwordpassword

The login process ...The login process ...The login process ...The login process ...

User account User account —— provides access to provides access to network resources.network resources.

Network administratorNetwork administrator or or supervisorsupervisor —— person responsible for setting person responsible for setting up user accounts and maintaining up user accounts and maintaining the network.the network.

Mapping Mapping —— assigning drive letters to assigning drive letters to network server disk drives.network server disk drives.

What drives are available??What drives are available??What drives are available??What drives are available??

View a directory or access files on network server drive F just as you would drives A and C.

Your workstation floppy drive A

Network server drive F

Your workstation hard disk drive C

Network printer

Using Programs on the NetworkUsing Programs on the NetworkUsing Programs on the NetworkUsing Programs on the Network

Step #1

Step #2

Step #3

Disk storage spaceDisk storage space Time and effort in updating Time and effort in updating

softwaresoftware Licensing costsLicensing costs

Sharing a program — with proper licensing many network users can access a program at the same time and save...

Parallel port

Workstation

Network printer

Using a Network PrinterUsing a Network PrinterUsing a Network PrinterUsing a Network Printer

The login process usually assigns a network printer to your workstation.

Output is redirected (captured) from the parallel port to the network printer.

Two documents are sentto a network printer at the same time . . .

Print Queue:1. Ceo.Doc2. Gnp.Doc

Ceo.doc arrives first

Gnp.doc arrives before printer completes Ceo.doc

Print queue Print queue —— special holding area special holding area on the network server where files are on the network server where files are stored until they are printed.stored until they are printed.

Network interface card (NIC) Network interface card (NIC) —— small circuit board that plugs into small circuit board that plugs into expansion slot.expansion slot.

– Key component for connecting your computer to a local area network– Sends data from a workstation over the network– Collects incoming data intended for your workstation

Network HardwareNetwork HardwareNetwork HardwareNetwork Hardware

Desktop network interface card (NIC)

Connecting NetworksConnecting NetworksConnecting NetworksConnecting Networks

Similar to Similar to telephone cabletelephone cable Has a plastic RJ-Has a plastic RJ-45 connector on 45 connector on either endeither end

Twisted pair cable (UTP) —

Wireless networks Wireless networks use radio or use radio or infrared signals to transmit data from infrared signals to transmit data from one network device to another.one network device to another.The network interface card contains The network interface card contains the transmitting devices.the transmitting devices.

Other Network ConnectorsOther Network ConnectorsOther Network ConnectorsOther Network Connectors

Provide mobilityProvide mobility Are used in environments where Are used in environments where

wiring is hard to installwiring is hard to install Can be good for temporary Can be good for temporary

installationsinstallations

Wireless networks:Wireless networks:Wireless networks:Wireless networks:

Software for NetworksSoftware for NetworksSoftware for NetworksSoftware for Networks

A network requires some special A network requires some special network software network software in addition to in addition to much of the same application much of the same application software typical of standalone software typical of standalone computers.computers.

Network license:Network license:Network license:Network license: Permits specified number of people Permits specified number of people

to use software on a networkto use software on a network Costs more than one single-user Costs more than one single-user

license but less than individual license but less than individual licenses for all network userslicenses for all network users

Available for most software Available for most software packages by contacting the packages by contacting the publisherpublisher

E-mailE-mailE-mailE-mail

Electronic mail (e-mail) Electronic mail (e-mail) is is correspondence conducted correspondence conducted between users on a computer between users on a computer network. network.

E-mail messages are E-mail messages are storedstored on a on a serverserver

When you read your mail, the When you read your mail, the server server forwardsforwards it to your it to your workstationworkstation

Store and forward Store and forward technology:technology:Store and forward Store and forward technology:technology:

Mail server

Your workstation

1. E-mail addressed to you is sent to the mail server

2. Mail stays on the mail server until you log on to your mail client.

3. Server forwards your mail to your workstation when you’re ready to read it.

VOIPVOIPVOIPVOIP

VoIP allows you to make telephone calls using the Internet.

Voice communication among the computers, free of charge

Calls to phone numbers for a fee

Streaming MediaStreaming MediaStreaming MediaStreaming Media Streaming media technology enables

you to include audio, video and other multimedia files into your web site.

Downloading vs StreamingDownloading vs StreamingDownloading vs StreamingDownloading vs Streaming Downloading :The user

downloads the file from the web server to her local hard disk, and then plays back the content using a player.

Streaming: The media Server sends data over the network only at the speed that is necessary for the client to render it properly and allows live content delivery.

More Internet ApplicationsMore Internet ApplicationsMore Internet ApplicationsMore Internet Applications FTP is a standard 

network protocol used to exchange and manipulate files over the Internet..

Instant Messaging, originally a Instant Messaging, originally a real-time communication via the real-time communication via the Internet using typed text and now Internet using typed text and now includes voice and videoincludes voice and video