Computer Communications and Networks: Understanding the Basics - Prof. Joseph Bullington, Study notes of Computer Science

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Discovering Computers 2009 Chapter 9 Communicati ons and Networks Chapter 9 Objectives Discuss the components required for successful communications Discuss the components required for successful communications Identify various sending and receiving devices Identify various sending and receiving devices Describe uses of computer communicationsDescribe uses of computer communications List advantages of using a networkList advantages of using a network Differentiate among client/server, peer-to-peer, and P2P networks Differentiate among client/server, peer-to-peer, and P2P networks Describe the various network communications standards Describe the various network communications standards Explain the purpose of communications software Explain the purpose of communications software Describe various types of lines for communications over the telephone network Describe various types of lines for communications over the telephone network Describe commonly used communications devices Describe commonly used communications devices Discuss different ways to set up a home network Discuss different ways to set up a home network Identify various physical and wireless transmission media Identify various physical and wireless transmission media Next Uses of Computer Communications What are some uses of communications technology? Nextp. 462 Uses of Computer Communications Video: Trillian Next CLICK TO START Uses of Computer Communications What are wireless messaging services? p. 463 - 464 Next Wireless instant messaging allows wireless mobile devices to exchange messages Text messaging allows users to send and receive short text messages on a phone or other mobile device Picture/video messaging allows users to send graphics, pictures, video clips, sound files, and short text messages Click to view Web Link, click Chapter 9, Click Web Link from left navigation, then click Video Messaging below Chapter 9 Uses of Computer Communications What are collaboration and groupware? Nextp. 467 Fig. 9-7  Web conference  Groupware is software that allows people work together and share information  Collaboration is working with other users connected to a server Click to view Web Link, click Chapter 9, Click Web Link from left navigation, then click Web Conferences below Chapter 9 Uses of Computer Communications What are voice mail and web services? Nextp. 468 Fig. 9-8  Voice mail is voice message converted to digital form  Web services describe standardized software that enables programmers to create applications that communicate with other remote computers over the Internet or on an internal business network Networks What is a network? Nextp. 469 Fig. 9-9  Collection of computers and devices connected via communications devices and transmission media Networks What is a client/server network? Nextp. 472 Fig. 9-13  One or more computers act as server and other computers, or clients, access server Networks What is a peer-to-peer network? Nextp. 473 Fig. 9-14  Simple network that connects fewer than 10 computers  Each computer, or peer, has equal capabilities Networks What is Internet peer-to-peer (P2P)? Nextp. 473 - 474 Fig. 9-15  Sometimes called a file sharing network  Enables users to connect to each other’s hard disks and exchange files directly Click to view Web Link, click Chapter 9, Click Web Link from left navigation, then click BitTorrent below Chapter 9 Networks What is a star network? Nextp. 475 Fig. 9-18  All devices connect to a central device (hub or switch)  All data transferred from one computer to another passes through hub or switch Networks What is an intranet? Nextp. 475 Extranet allows customers or suppliers to access part of company’s intranet Typically includes connection to Internet Makes information accessible to employees Internal network that uses Internet technologies Network Communications Standards What are Ethernet and token ring? Nextp. 476 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 Token ring technology controls access to network by requiring devices to pass a special signal, called tokenClick to view Web Link, click Chapter 9, Click Web Link from left navigation, then click Ethernet below Chapter 9 Network Communications Standards What are UWB, IrDA, RFID, WiMAX, and Wireless Applications Protocol (WAP)? Nextp. 478 - 480 Click to view Web Link, click Chapter 9, Click Web Link from left navigation, then click WiMAX below Chapter 9 IrDA specification allows data to be transferred wirelessly via infrared light waves IrDA specification allows data to be transferred wirelessly via infrared light waves Wireless Applications Protocol (WAP) allow wireless mobile devices to access Internet ireless Applications Protocol ( AP) allow wireless mobile devices to access Internet Radio Frequency Identification (RFID) uses radio signals to communicate with a tag placed in an object Radio Frequency Identification (RFID) uses radio signals to communicate with a tag placed in an object Worldwide Interoperability for Microwave Access (WiMAX or 802.16) standard that specifies how wireless devices communicate over the air in a wide area orldwide Interoperability W for icrowave Access ( i AXM W M or 802.16) standard that specifies how wireless devices communicate over the air in a wide area UWB specification allows data to be transferred wirelessly via short-range radio waves U B specification allows data to be transferred wirelessly via short-range radio waves Communications Software What is communications software? Nextp. 480 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 Communications Over the Telephone Network What is the public switched telephone network (PSTN)? Nextp. 481 Fig. 9-23  Worldwide telephone system that handles voice-oriented telephone calls Communications Devices What are examples of communications devices? Nextp. 484 Common types are dial-up modems, ISDN and DSL modems, cable modems, wireless modems, network cards, wireless access points, routers, and hubs ISDN and DSL modems send and receive data from ISDN and DSL lines Communications Devices What is a dial-up modem? Nextp. 485  A dial-up modem converts digital signals to analog signals and vice versa  Usually in the form of an adapter card Communications Devices What are ISDN and DSL modems? Nextp. 485 Communications devices that send and receive digital ISDN and DSL signals o unications devices that send and receive digital IS and S signals Usually external devices in which one end connects to a telephone line and the other end connects to a port on the system unit sually external devices in hich one end connects to a telephone line and the other end connects to a port on the syste unit Communications Devices What is a network card? Nextp. 486 - 487 Fig. 9-30  Adapter card, PC Card, ExpressCard module, USB network adapter, or flash card that enables computer or device to access network  Sometimes called network interface card (NIC) Communications Devices What is a wireless access point? Nextp. 487 Fig. 9-31  Central communications device that allows computers and devices to transfer data wirelessly among themselves or wirelessly to a wired network Communications Devices What is a router? Nextp. 488 Fig. 9-32  Connects computers and transmits data to correct destination on network  Routers forward data on Internet using fastest available path Click to view Web Link, click Chapter 9, Click Web Link from left navigation, then click Wireless Routers below Chapter 9  Some routers have a built-in hardware firewall Communications Channel What is a communications channel? Nextp. 491  Transmission media on which data travels in communications system Bandwidth is amount of data that can travel over a communications channel Transmission media are materials or substances capable of carrying one or more signals Communications Channel How is a request sent over the Internet using a communications channel? Nextp. 491 Fig. 9-35 Physical Transmission Media What is physical transmission media? Nextp. 492 Fig. 9-36  Wire, cable, and other tangible materials used to send communications signals Wireless Transmission Media What is wireless transmission media? Nextp. 494 Fig. 9-40  Used when inconvenient, impractical, or impossible to install cables  Includes Bluetooth and IrDA Wireless Transmission Media What are broadcast radio and cellular radio? Nextp. 494 and 495 Fig. 9-41  Broadcast radio distributes radio signals over long and short distances  Cellular radio is form of broadcast radio used for mobile communications Click to view Web Link, click Chapter 9, Click Web Link from left navigation, then click 4G Networks below Chapter 9 Wireless Transmission Media What is a microwave station? Nextp. 496 Fig. 9-42  Earth-based reflective dish used for microwave communications  Must transmit in straight line with no obstructions