Data and Computer Data and Computer Communications Communications Chapter 1 Chapter 1 Introduction Introduction The main topics of this book: The main topics of this book: Exchange of data between Exchange of data between two directly two directly Connected devices Connected devices Transmission Transmission interfacing interfacing data link control data link control multiplexing multiplexing Net connection Net connection   WAN WAN   LAN LAN Protocol Protocol   Protocol architecture Protocol architecture Data communication Data communication PLAN OF THE TEXT PLAN OF THE TEXT Overview Overview   Introduction of the topics Introduction of the topics   Discussion of protocols Discussion of protocols Data Communication Data Communication   Exchange of data/transmission/interfacing/link control/multiplex Exchange of data/transmission/interfacing/link control/multiplex ing ing Wide Area Networks Wide Area Networks   Switching technologies (packet switching/circuit switching/ATM) Switching technologies (packet switching/circuit switching/ATM)   Congestion control Congestion control Local Area Networks Local Area Networks   Transmission media Transmission media   Topologies Topologies   Medium access control protocols Medium access control protocols   Specific standardized LAN systems Specific standardized LAN systems Networking Protocols Networking Protocols   Protocol architecture Protocol architecture Chapter 1 introduction Chapter 1 introduction Computer science Data communication merge1970s ~ 1980s Data communication Voice communication No fundamental diferences Data processing equipment Data communication equipment Video communication Single-processor computer Multi-processor computer LAN、MAN、WAN A Communications Model A Communications Model Source Source   generates data to be transmitted generates data to be transmitted Transmitter Transmitter   Converts data into transmittable signals Converts data into transmittable signals Transmission System Transmission System   Carries data Carries data Receiver Receiver   Converts received signal into data Converts received signal into data Destination Destination   Takes incoming data & process Takes incoming data & process Simplified Communications Simplified Communications Model Model - - Diagram Diagram Key Communications Tasks Key Communications Tasks Transmission System Utilization Transmission System Utilization Interfacing Interfacing Signal Generation Signal Generation Synchronization Synchronization Exchange Management Exchange Management Error detection and correction Error detection and correction Addressing and routing Addressing and routing Recovery Recovery Message formatting Message formatting Security Security Network Management Network Management Simplified Data Simplified Data Communications Model Communications Model Networking Networking Point to point communication not usually Point to point communication not usually practical practical   Devices are too far apart Devices are too far apart   Large set of devices would need impractical Large set of devices would need impractical number of connections number of connections Solution is a communications network Solution is a communications network Simplified Network Model Simplified Network Model