Introduction to Data Communications and Computer Networks

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George Ellis
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1 1/20 Introduction to Data Communications and Computer Networks Surasak Sanguanpong Last updated: 2 November /20 Outline Data Communications Communications Networks Standards Standards Organizations 1

2 What is data communications? 3/20 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 Communication Tasks 4/20 Interfacing Signal generation Message formatting Addressing Flow control Routing Error detection Error correction Recovery Protection Transmission system utilization Exchange management System management 2

3 A Communications Model 5/20 Source system input information Destination system output information Source Device input data Communications system Destination device output data Transmitter transmitted signal Transmission medium received signal Receiver A Communications Example 6/20 Source system A Destination system A computer Telephone Networks computer modem modem 3

4 7/20 Communications Networks Local Area Network () Categories of Networks Metropolitan Area Network (MAN) Wide Area Network (WAN) hub/switch hub/switch hub/switch stations stations stations General Characteristics : Confined geographical area Under single management High data rate 8/20 router hub/switch servers 4

5 MAN 9/20 A network which cover an entire city A single network or a number of connected s Public city network WAN 10/20 A network that cover a relatively broad geographic area It often uses long-distance transmission facilities provided by public carriers 5

6 Internetwork 11/20 Collection of networks interconnected by routers and other devices WAN MAN Communications System New generation of switching technologies provide improved services to home and workplace 12/20 Frame Relay Network ADSL CATV Cable Modem ATM Network Internet Leased Line ISDN Network PSTN Network Modem E/T-carrier 6

7 Standards 13/20 De facto Standards Standards without any formal plan De jure Formal, legal standards adopted by some authorized standardization body Standards Organizations 14/20 ITU-T ISO IETF IEEE ANSI EIA 7

8 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 16/20 ISO International Standards Organization An International standard organization that develops standard for variety of fields 8

9 IETF 17/20 Internet Engineering Task Force a large open international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture IEEE 18/20 Institute of Electrical and Electronics Engineers The largest professional group involved in standards for computing, communications, electrical and electronics 9

10 ANSI 19/20 American National Standard Institute U.S. nonprofit organization EIA 20/20 Electronic Industries Alliance A nonprofit organization devoted to the promotion of electronics manufacturing 10

Introduction to WAN Technologies

CHAPTER 3 Introduction to WAN Technologies This chapter introduces the various protocols and technologies used in wide- area network (WAN) environments. Topics summarized here include point-to-point links,