computers © 2005 prentice-hall, inc.slide 1. computers chapter 6 networks ( 網路 ) and networking...

Computers

© 2005 Prentice-Hall, Inc. Slide 1

Computers

Chapter 6

Networks ( 網路 ) and Networking ( 網路連接 )


ComputersChapter 6 – Networks and Networking

Objectives ( 目標 ) Apply the concept ( 觀念 ) of connectivity ( 連接性 ) to your life Understand data communications hardware ( 硬體 ) Identify ( 認識 ) data transmissions services ( 服務 )Understand the various ( 各樣 ) network topologiesRecognize ( 認識 ) the potential ( 潛力 ) of home networking


ComputersNetworks and Networking

Our Wired ( 連線 )World Connectivity – the degree ( 程度 ) to which software ( 軟體 ), hardware, and databases ( 資料庫 ) are functionally ( 功能 ) linked



Our Wired World Cooperative ( 合作式 ) processing

Intracompany ( 公司內 ) networking – cooperation ( 合作 ) within the company Intercompany ( 公司間 ) networking – cooperation with other companies and customers ( 客戶 )



Our Wired World Intranet ( 內網路 ) –internal network based on Internet technology Extranet ( 萬網路 ) – an extension ( 擴充 ) of an intranet, partially ( 部分 ) available ( 可用 ) to customers and suppliers ( 供應商 )



Our Wired World Virtual ( 虛擬 ) Private ( 私人 ) Network (VPN) – network transmissions ( 傳輸 ) are tunneled ( 通往 ) through the Internet Tunneling ( 通道 ) – one network uses another to send data



Data Communications HardwareData communications or telecommunications ( 電信 ) – distribution ( 播散 ) of data



Data Communications Hardware Server ( 伺服 ) computers – central computers that control the network Client ( 客戶 ) computers – computers, linked to a server, that create ( 產生 ) the network



Data Communications Hardware Proxy ( 代理 ) server computers – handle some requests ( 要求 ), hand others to the actual server computers



Data Communications Hardware Telephone-link modem ( 數據機 ) – converts ( 轉換 ) analog signals ( 類比信號 ) to digital ( 數位 ) and digital signals to analog Analog – voice communication, such as over a telephone lineDigital – 1’s and 0’s used to represent data in a computer



Data Communications Hardware Modem

Internal ( 內裝 )External ( 外接 )Voice/data/fax modem



Data Communications Hardware Cable modem – provides Internet access via cable television lines DSL (Digital Subscriber Line) – Internet access via special ( 特殊 ) line provided ( 提供 ) by a telephone company Satellite ( 衛星 ) modem – Internet access via communications satellite



Data Communications Hardware Network interface card (NIC) – also called network card and network adapter

Needed to connect a personal computer to a network Ethernet ( 乙太網 ) – de facto ( 事實上的 ) standard ( 標準 )



Data Communications Hardware Gateway ( 閘道 ) – allows ( 允許 ) for communication between networks using different ( 不同 ) protocols ( 協定 ) Router ( 路由器 ) – routes ( 安排傳送 ) messages ( 訊息 ) to the appropriate ( 適當 ) destination ( 目的地 )Gateway router – both functions in one device



Data Communications Hardware Message

Source ( 來源 ) – device that sends ( 送 ) the messageDestination – device that receives ( 接收 ) the message Handshaking ( 握手 ) – router establishes ( 建立 ) the connection between the source and the destination



Data Communications Hardware Network address – assigned to each computer on a network; used to send messages to the appropriate destination Backbone ( 主榦 ) – the routers, gateways, and other equipment that link the computers of the network



Data Communications Hardware Hub – expands the number of nodes on a network

Half-duplex ( 半雙工 ) – data can only be sent in one direction at a time

Switch ( 交換器 ) – acts like a hub for a local area network (LAN)

Full-duplex ( 全雙工 )– data can be sent in both directions at once



Data Communications Hardware Terminals ( 終端機 )

Video Display ( 顯示 )Terminal – input/output deviceThin ( 輕 ) client – smart terminal, capable ( 能夠 ) of some processing



Data Communications Hardware Telephony ( 電話電腦 ) – integration ( 整合 ) of telephones and computers



Data Communications HardwareAutomatic Teller Machine (ATM, 自動櫃員機 ) – used in banking ( 銀行 ) Point-of-Sale (POS, 銷售點 ) terminals – used in retail ( 零售 )



The Data Communications ChannelCommunications channel – media ( 媒體 ) a message must pass through on a network

LineLinkPipe ( 管路 )



The Data Communications ChannelTransmission media ( 媒體 )Measured ( 量測 ) in bits per second (bps)



The Data Communications ChannelTwisted-pair wire ( 絞線 )

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



The Data Communications ChannelCoaxial cable ( 同軸電纜 ) – high capacity channel, capable of speeds up to 10 M bpsFiber optic cable ( 光纖電纜 ) – carries ( 載 ) data as electrical signals



The Data Communications ChannelWireless ( 無線 ) communication

Microwave ( 微波 ) signal – sent from one transmitter ( 發射器 ) to anotherRadio frequency (RF, 射頻 ) signal – line-of-sight



The Data Communications ChannelCommunications satellite – repeater ( 強波器 ) for microwave transmissions in geosynchronous orbit ( 地球同步軌道 )Geosynchronous orbit – 22,300 miles above the earth



The Data Communications ChannelWireless networks

Access points (AP, 擷取點 ) – college campuses ( 校園 ), coffee shops, local area networks

Wi-Fi – approximately ( 大約 ) 300 foot range ( 範圍 )Bluetooth – approximately 30 foot range



The Data Communications ChannelWireless Application ( 應用 ) Protocol (WAP)

Internet access standard for wireless devices such as cell phones



The Data Communications ChannelFuture of wireless

Multichannel Multipoint ( 多通路多點 ) Distribution Service (MMDS)Local Multipoint Distribution Service (LMDS)



The Data Communications ChannelCommon carriers

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



The Data Communications ChannelCommunications protocols ( 通訊協定 ) – rules established to govern ( 管理 ) the way data are transmitted in a computer network Asynchronous transmission ( 非同步通訊 ) – data sent on an as-needed ( 隨需求 ) basisSynchronous transmission ( 同步通訊 ) – source and destination operate in timed synchronization



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



NetworksTypes of Networks

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



NetworksTypes of Networks

Metropolitan ( 大都市 ) Area Network (MAN) – network that encompasses ( 包含 ) a cityWide ( 廣域 ) Area Network (WAN) – nodes of the network are geographically ( 地理 ) distant ( 遠 )



NetworksLAN resources ( 資源 ) that can be shared

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



NetworksLAN access methods

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

Logical topology ( 網路拓撲 )



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



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



NetworksLAN software

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



NetworksLAN software

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



NetworksApplication software for LANs

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



NetworksApplication software for LANs

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



NetworksShared ( 共享 ) applications software

Groupware ( 群體 ) – allows a group of people to work on a project ( 計畫 )



NetworksShared applications software

Electronic mail (e-mail)Instant messagingCalendar ( 行事曆 ) and scheduling ( 日程表 )Brainstorming ( 腦力激盪 )Shared whiteboarding ( 白板討論 )



NetworksShared applications software

Setting priorities ( 優先次序 )Electronic conferencing ( 電子會議 )Electronic forms ( 書表 )



NetworksHome network – small LAN in the home



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



NetworksHome network decisions

How many computers? Where will they be placed?How much do you want to spend ( 花費 )?What is your networking expertise ( 專業 )?Do you expect ( 預期 ) the network to grow?What applications ( 應用程式 ) do you want to run?



NetworksSteps to installing ( 安裝 ) 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


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


computers © 2005 prentice-hall, inc.slide 1. computers chapter 6 networks ( 網路 ) and networking...

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