Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 221.1Chapter 1IntroductionCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.1.21-1 DATA COMMUNICATIONS1-1 DATA COMMUNICATIONSThe term The term telecommunicationtelecommunication means communication at a means communication at a distance. The word distance. The word datadata refers to information presented refers to information presented in whatever form is agreed upon by the parties creating in whatever form is agreed upon by the parties creating and using the data. and using the data. Data communicationsData communications are the are the exchange of data between two devices via some form of exchange of data between two devices via some form of transmission medium such as a wire cable. transmission medium such as a wire cable. ComponentsData RepresentationData FlowTopics discussed in this section:Topics discussed in this section:1.3Figure 1.1 Five components of data communication1.4Data Representation• Text• Numbers• Images• Audio• Video• Voice1.5Figure 1.2 Data flow (simplex, half-duplex, and full-duplex)1.61-2 NETWORKS1-2 NETWORKSA A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) ) connected by communication connected by communication linkslinks. A node can be a . A node can be a computer, printer, or any other device capable of sending computer, printer, or any other device capable of sending and/or receiving data generated by other nodes on the and/or receiving data generated by other nodes on the network.network.Distributed ProcessingNetwork CriteriaPhysical StructuresNetwork ModelsCategories of NetworksInterconnection of Networks: InternetworkTopics discussed in this section:Topics discussed in this section:1.7Communication Devices: Examples Bluetooth alarm clockswitchWireless routerCommon communication devicesNon-common communication devicesBluetooth watches1.8Network Criteria• Performance:•Throughput •Delay• Reliability• Security1.9Figure 1.3 Types of connections: point-to-point and multipoint1.10Figure 1.4 Categories of topology1.11Figure 1.5 A fully connected mesh topology (five devices)12345n(n-1) half-duplex linksn(n-1)/2 duplex links1.12Figure 1.6 A star topology connecting four stations1.13Figure 1.7 A bus topology connecting three stations1.14Figure 1.8 A ring topology connecting six stations1.15Figure 1.9 A hybrid topology: a star backbone with three bus networks1.16Categories of Networks1.17Figure 1.10 An isolated LAN connecting 12 computers to a hub in a closet1.18Figure 1.11 WANs: a switched WAN and a point-to-point WAN1.19Figure 1.12 A heterogeneous network made of four WANs and two LANs1.201-3 THE INTERNET1-3 THE INTERNETThe The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives. It has affected the way we do business as well as the lives. It has affected the way we do business as well as the way we spend our leisure time. The Internet is a way we spend our leisure time. The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use. information to our fingertips and organized it for our use. A Brief HistoryThe Internet Today (ISPs)Topics discussed in this section:Topics discussed in this section:1.21Figure 1.13 Hierarchical organization of the Internet1.221-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDSIn this section, we define two widely used terms: In this section, we define two widely used terms: protocolsprotocols and and standardsstandards. First, we define protocol, which is . First, we define protocol, which is synonymous with rule. Then we discuss standards, which synonymous with rule. Then we discuss standards, which are agreed-upon rules.are agreed-upon rules.ProtocolsStandardsStandards OrganizationsInternet StandardsTopics discussed in this section:Topics discussed in this