Chapter 9 Communications and Networks

Transcription

1 Chapter 9 Objectives Chapter 9 and Discuss the the components required for for successful Identify various sending and and receiving devices Describe uses of of computer List advantages of of using a network Differentiate among client/server, peer-to-peer, and and P2P networks Describe the the various network technologies Explain the the purpose of of software Describe various types of of lines for for over the the telephone network Describe commonly used devices Discuss different ways to to set set up up a home network Identify various physical and and wireless transmission media What are computer? Process in which two or more computers or devices transfer data, instructions, and information smart phones mainframe computers set-top boxes notebook computers GPS receivers servers Web-enabled PDAs desktop computers What is needed for successful? Sending device initiates instruction to transmit data, instructions, or information device connects the channel to the receiving device device connects the sending device to the channel Receiving device accepts transmission of data, instructions, or information channel media on which data, instructions, or information travel Tablet PCs p. 460 Fig. 9-1 p. 460 Uses of Computer What are some uses of technology? Uses of Computer What are Internet telephony and Internet printing? Instant Messaging Internet Web Folders Chat Rooms Web Video Conferencing Newsgroups Fax Machine or Computer Fax/Modem FTP Internet telephony enables you to talk to other people over the Internet Sometimes called Voice over IP Internet printing allows you to print to network printer from anywhere in the world p. 463 p

2 Uses of Computer Uses of Computer What are Web services? Software that enables programmers to create applications that communicate with other remote computers What are collaboration and groupware? Collaboration is working with other users connected to a server Microsoft s NetMeeting allows collaboration Groupware is software that allows people to share information p. 464 Fig. 9-4 p. 465 Fig. 9-5 Uses of Computer Uses of Computer What are public Internet access points and cybercafés? Public Internet access point allows wireless connection to Internet in public location Cybercafé is coffee house that provides computers with Internet access then click Public Internet Access Points p. 466 Fig. 9-6 What is a global positioning system (GPS)? Step 1. GPS satellites orbit Earth. Every thousandth of a second, each satellite sends a signal that indicates its current position to the GPS server. Click to view video then click GPS p. 464 Fig. 9-7 Step 2. A GPS receiver (such as in a car, a PDA, a watch, a handheld device, or a collar) determines its location on Earth by analyzing at least 3 separate satellite signals from the 24 satellites in orbit. Uses of Computer What are voice mail and wireless messaging services? Voice mail is voice message converted to digital form Wireless messaging services include: Text Messaging Instant Messaging Picture Messaging What is a network? Collection of computers and devices connected via devices and transmission media p. 468 Fig. 9-8 p. 469 Fig

3 What is a local area network (LAN)? What is a wide area network (WAN)? Network in limited geographical area such as home or office building Metropolitan area network (MAN) connects LANs in city or town then click LAN p. 471 Fig Network that covers large geographic area using many types of media Internet is world s largest WAN p. 472 Fig What is a client/server network? What is a peer-to-peer network? One or more computers act as server and other computers, or clients, access server p. 472 Fig Simple network that connects fewer than 10 computers Each computer, or peer, has equal capabilities p. 473 Fig What is Internet peer-to-peer (P2P)? Enables users to connect to each other s hard disks and exchange files directly What is a bus network? All computers and devices connect to central cable, or bus Example of network topology (layout of devices in network) then click P2P p. 473 Fig p. 474 Fig Popular topologies are bus, ring, and star 3

4 What is a ring network? Cable forms closed ring, or loop, with all computers and devices arranged along ring Data travels from device to device around entire ring, in one direction What is a star network? All devices connect to a central device, called hub All data transferred from one computer to another passes through hub p. 474 Fig p. 475 Fig What are Ethernet and token ring? Ethernet technology allows computers to contend for access to network If two computers send data at same time, a collision occurs and computers must send again What are TCP/IP and ? TCP/IP (Transmission Control Protocol/Internet Protocol) technology transmits data by breaking it up into small pieces, or packets Commonly used for Internet transmissions is family of standards for wireless LANs click Chapter 9, Click Web Link then click Ethernet p. 475 Token ring technology controls access to network by requiring devices to pass a special signal, called token p. 476 Fig What is Bluetooth? Short-range radio waves transmit data between Bluetooth devices p. 476 Fig What are IrDA, RFID, and Wireless Applications Protocol (WAP)? Radio Frequency Identification (RFID) Click to view video IrDA specification allows data data to to be be transferred wirelessly via via infrared light light waves uses uses radio radio signals to to communicate with with a tag tag placed in in an an object Wireless Applications Protocol (WAP) allow wireless mobile devices to to access Internet then click WAP p

5 What is an intranet? Software What is software? Internal network that uses Internet technologies Makes information accessible to employees Typically includes connection to Internet Extranet allows customers or suppliers to access part of company s intranet Programs that help users establish connection to Internet, other network, or another computer Programs that help users manage transmission of data, instructions, and information Programs that provide an interface for users to communicate with one another p. 478 p. 478 Software Over the Telephone Network What is an example of software? Configures home or office network and connects devices to existing network Step 1. After you start Step 2. Enter the name of your Internet service provider. the New Connection Wizard and select Connect to the Internet and Set up my connection manually in the dialog boxes, click Connect using a dial-up modem. Step 3. Enter your Internet service provider s telephone number. What is the public switched telephone network (PSTN)? Worldwide telephone system that handles voice-oriented telephone calls Step 4. Enter your account information. Step 5. Click the Finish button to create the Internet connection. p. 479 Fig p. 480 Fig Over the Telephone Network Over the Telephone Network What is a dial-up line? Temporary connection using telephone line for Costs no more than making regular call Computers at any two locations can establish a connection using modems and telephone network What is a dedicated line? Always-on connection between two devices Four types are ISDN line, DSL, T-carrier line, and ATM p. 480 Fig p. 481 Fig

6 Over the Telephone Network What is an ADSL (asymmetric digital subscriber line)? What are examples of devices? Popular type of DSL (Digital Subscriber Line) Faster when receiving data than when sending data Common types are dial-up modems, ISDN and DSL modems, cable modems, network cards, wireless access points, routers, and hubs ISDN and DSL modems send and receive data from ISDN and DSL lines Ideal for Internet access then click DSL p. 482 Fig p. 482 What is a dial-up modem? What are ISDN and DSL modems? Converts digital signals to analog signals and vice versa Notebook computers often use PC Card modem devices devices that that send send and and receive receive digital digitalisdn ISDN and and DSL DSL signals signals Usually Usually external externaldevices devices in inwhich which one one end connects to a telephone line end connects to a telephone lineand and the the other other end end connects connects to to aa port port on on the the system system unit unit then click Dial-Up Modems p. 483 Figs p. 484 What is a cable modem? What is a network card? Sends and receives data over cable television network Much faster than dial-up modem or ISDN Sometimes called a broadband modem p. 484 Fig Adapter card, PC Card, or compact flash card that enables computer or device to access network Sometimes called network interface card (NIC) p. 485 Fig

7 What is a wireless access point? What is a router? Central device that allows computers and devices to transfer data wirelessly among themselves or to wired network p. 485 Fig Connects computers and transmits data to correct destination on network Routers forward data on Internet using fastest available path then click Routers p. 486 Fig Home What is a hub? What is a home network? Device that provides central point for cables in network Multiple computers connected in home Several types of home networks Click to view animation p. 486 Fig Ethernet connect computers via cable Powerline cable use electrical lines in house Phoneline use telephone lines HomeRF (radio frequency) wireless then click Home p. 487 Fig Channel Channel What is a channel? How is a request sent over the Internet using a channel? Transmission media on which data travels in system Step 1. The sending device requests information using either a physical transmission media or a wireless transmission media. Transmission media are materials capable of carrying one or more signals Step 2. When the request leaves the ISP, it travels over T1 lines, microwave stations, earth-based stations, and satellites until it reaches the Internet backbone. Bandwidth is amount of data that can travel over channel Step 3. The request travels over T3 lines along the Internet backbone. Step 4. The Request travels over T1 lines until it reaches the destination network server. p. 489 p. 489 Fig

8 Physical Transmission Media Physical Transmission Media What is physical transmission media? What are twisted-pair cable and coaxial cable? Wire, cable, and other tangible materials used to send signals Transfer Rates for Various Types of LANs Using Physical Transmission Media p. 490 Fig Twisted-pair cable is used for telephone systems and network cabling Coaxial cable is often used for cable television wiring p. 490 Fig Physical Transmission Media Wireless Transmission Media What is fiber-optic cable? What is wireless transmission media? Capable of carrying significantly more data at faster speeds than wire cables Less susceptible to interference (noise) and, therefore, more secure Smaller size (thinner and lighter) p. 491 Fig Used when inconvenient, impractical, or impossible to install cables Includes Bluetooth and IrDA p. 491 Fig Wireless Transmission Media Wireless Transmission Media What are broadcast radio and cellular radio? What is a microwave station? Broadcast radio distributes radio signals over long and short distances Cellular radio is form of broadcast radio used for mobile then click Cellular p. 492 Fig Earth-based reflective dish used for microwave Must transmit in straight line with no obstructions p. 493 Fig

9 Wireless Transmission Media Summary of and What is a satellite? Space station that receives microwave signals from earth-based station, amplifies signals, and broadcasts signals back to any number of earthbased stations terminology and applications How to to join computers into a network Various devices, media, and procedures Chapter 9 Complete p. 494 Fig