1/20 Introduction to Data Communications and Computer Networks Surasak Sanguanpong nguan@ku.ac.th http://www.cpe.ku.ac.th/~nguan Last updated: 2 November 2004 Applied Network Research Group Department of Computer Engineering, Kasetsart University 2/20 Outline Data Communications � Communications Networks � Standards � Standards Organizations � Applied Network Research Group Department of Computer Engineering, Kasetsart University 1
3/20 What is data communications? Telecommunications : literally means communication � over a distance. All type of communications such as telephone, data (computers), cable television, and wireless communications have converged under the umbrella of the telecommunications field Data communications is the subset of � telecommunications that involves the transmission and reception of data to and from computers and components of computer systems Applied Network Research Group Department of Computer Engineering, Kasetsart University 4/20 Communication Tasks � Addressing � Interfacing � Flow control � Signal generation � Routing � Message formatting � Error detection � Transmission system � Error correction utilization � Recovery � Exchange management � Protection � System management Applied Network Research Group Department of Computer Engineering, Kasetsart University 2
5/20 A Communications Model Source system Destination system input information output information Source Source Destination Destination Communications Device Device device device system input data output data Transmission Transmission Transmitter Transmitter Receiver Receiver medium medium received transmitted signal signal Applied Network Research Group Department of Computer Engineering, Kasetsart University 6/20 A Communications Example Source system Destination system A A computer computer Telephone Networks 110011 110011 modem modem Applied Network Research Group Department of Computer Engineering, Kasetsart University 3
7/20 Communications Networks Local Area Network Local Area Network (LAN) (LAN) Categories of Categories of Metropolitan Area Network Metropolitan Area Network Networks Networks (MAN) (MAN) Wide Area Network Wide Area Network (WAN) (WAN) Applied Network Research Group Department of Computer Engineering, Kasetsart University 8/20 LAN hub/switch stations General Characteristics : � Confined geographical area hub/switch stations � Under single management � High data rate hub/switch stations servers hub/switch router Applied Network Research Group Department of Computer Engineering, Kasetsart University 4
9/20 MAN A network which cover an entire city • A single network or a number of • connected LANs LAN LAN Public city network LAN LAN Applied Network Research Group Department of Computer Engineering, Kasetsart University 10/20 WAN • A network that cover a relatively broad geographic area • It often uses long-distance transmission facilities provided by public carriers Applied Network Research Group Department of Computer Engineering, Kasetsart University 5
11/20 Internetwork Collection of networks interconnected by routers and other • devices LAN LAN WAN LAN LAN LAN MAN Applied Network Research Group Department of Computer Engineering, Kasetsart University 12/20 Communications System • New generation of switching technologies provide improved services to home and workplace Cable Frame Relay Modem ADSL CATV Network Internet Leased Line ATM Network ISDN E/T-carrier Network PSTN Network Modem Applied Network Research Group Department of Computer Engineering, Kasetsart University 6
13/20 Standards De facto De facto Standards without any � formal plan Standards Standards De jure De jure Formal, legal standards adopted by � some authorized standardization body Applied Network Research Group Department of Computer Engineering, Kasetsart University 14/20 Standards Organizations ITU-T ISO IETF IEEE ANSI EIA Applied Network Research Group Department of Computer Engineering, Kasetsart University 7
15/20 ITU-T International Telecommunications Union- � Telecommunication Standard Sector International standard � organization that develops standard for telecommunications Some well known � standards V series � X series � H series � G Series � Applied Network Research Group Department of Computer Engineering, Kasetsart University 16/20 ISO International Standards Organization � An International � standard organization that develops standard for variety of fields Applied Network Research Group Department of Computer Engineering, Kasetsart University 8
17/20 IETF � Internet Engineering Task Force a large open international � community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture Applied Network Research Group Department of Computer Engineering, Kasetsart University 18/20 IEEE Institute of Electrical and Electronics Engineers � The largest professional � group involved in standards for computing, communications, electrical and electronics Applied Network Research Group Department of Computer Engineering, Kasetsart University 9
19/20 ANSI American National Standard Institute � U.S. nonprofit � organization Applied Network Research Group Department of Computer Engineering, Kasetsart University 20/20 EIA Electronic Industries Alliance � A nonprofit organization � devoted to the promotion of electronics manufacturing Applied Network Research Group Department of Computer Engineering, Kasetsart University 10
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