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Data Communication CS601 CS601-Data Communication VU Table of Contents Lecture

Data Communication CS601 CS601-Data Communication VU Table of Contents Lecture No. 1 .....................................................................................................3 Lecture No. 2 ...............................................................................................................12 Lecture No. 3 ...............................................................................................................17 Lecture No. 4 ...............................................................................................................22 Lecture No. 5 ...............................................................................................................28 Lecture No. 6 ...............................................................................................................33 Lecture No. 7 ...............................................................................................................39 Lecture No. 8 ...............................................................................................................44 Lecture No. 9 ...............................................................................................................49 Lecture No. 10 .............................................................................................................52 Lecture No. 11 .............................................................................................................56 Lecture No. 12 .............................................................................................................61 Lecture No. 13 .............................................................................................................66 Lecture No. 14 .............................................................................................................70 Lecture No. 15 .............................................................................................................75 Lecture No. 16 .............................................................................................................79 Lecture No. 17 .............................................................................................................84 Lecture No. 18 .............................................................................................................89 Lecture No. 19 .............................................................................................................95 Lecture No. 20 .............................................................................................................98 Lecture No. 21 ...........................................................................................................101 Lecture No. 22 ...........................................................................................................108 Lecture No. 23 ...........................................................................................................114 Lecture No. 24 ...........................................................................................................118 Lecture No. 25 ...........................................................................................................124 Lecture No. 26 ...........................................................................................................130 Lecture No. 27 ...........................................................................................................135 Lecture No. 28 ...........................................................................................................142 Lecture No. 29 ...........................................................................................................146 Lecture No. 30 ...........................................................................................................156 Lecture No. 31 ...........................................................................................................160 Lecture No. 32 ...........................................................................................................165 Lecture No. 33 ...........................................................................................................169 Lecture No. 34 ...........................................................................................................174 Lecture No. 35 ...........................................................................................................179 Lecture No. 36 ...........................................................................................................183 Lecture No. 37 ...........................................................................................................188 Lecture No. 38 ...........................................................................................................193 Lecture No. 39 ...........................................................................................................199 Lecture No. 40 ...........................................................................................................205 Lecture No. 41 ...........................................................................................................210 Lecture No. 42 ...........................................................................................................218 Lecture No. 43 ...........................................................................................................227 Lecture No. 44 ...........................................................................................................233 Lecture No. 45 ...........................................................................................................239 © Copyright Virtual University of Pakistan 2 CS601-Data Communication VU LECTURE #1 Course Outline The course will consist of : –45 lectures –10-14 assignments –2exams (1 midterm and 1 final) –GMDB Grading Criteria: –One Midterm: 35 % –Final Exam: 45% –Assignments: 15% –GMDB: 5% Textbook “Data Communications and Networking” 4th Edition by Behrouz A. Forouzan “Data and Computer Communication” 6th Edition by William Stallings © Copyright Virtual University of Pakistan 3 CS601-Data Communication VU INTRODUCTION TO DATA COMMUNICATION DEFINITION OF DATA COMMUNICATION “Data Communication is the exchange of Information from one entity to the other using a Transmission Medium”. DEFINITION OF DATA COMMUNICATION (Cont’d) As you can clearly notice, the definition of Data Communication although Simple leaves many questions unanswered: ¾ Exchange?????? ¾ Information????? ¾ Entities??????? ¾ Transmission???? ¾ Medium???? We will try to answer all these Questions in this Course History of Data Communication Data communications history represents a blend of histories, including: ¾ The history of the telecommunications industry ¾ The history of data communications, and ¾ The history of the Internet Telegraph 1837 Samuel Morse Modern telecommunication industry began in 1837 with the invention of the telegraph by Samuel Morse This led to building a telecommunications infrastructure of poles and wires as well as to the development of communication hardware and protocols Telephone 1876 Alexander Graham Bell Invention of telephone by Alexander Graham Bell in 1876 and the development of wireless communication technology by Guglielmo Marconi in the 1890s set the stage for today’s communication industry By 1950’s By 1950s, telephone and telegraph companies had developed a network of communication facilities throughout the industrialized world 1970’S Although development of databases, languages, operating systems, and hardware was strong from 1950s to 1970s, large-scale data communication systems did not emerge until the 1970s. This was stimulated by 3 major developments: ¾ Large-scale integration of circuits reduced cost and size of terminals and communication equipment © Copyright Virtual University of Pakistan 4 CS601-Data Communication VU ¾ New software systems that facilitated the development of data communication networks ¾ Competition among providers of transmission facilities reduced the cost of data circuits TODAY’S EVERGHANGING & BUSY WORLD o Today’s fast world demands better, secure and most of all FAST ways of communication o Gone are the days when you had to wait a couple of weeks to get a letter from USA o Why wait ONE week when you can get the information you require in just a split of a second, using what we know by the name of “DATA COMMUNICATION”. HOW TO ACHIEVE THIS? o How to achieve this ACCURACY, SECURITY and SPEED for the transfer of this information? o What HARDWARE and the SOFTWARE is needed? o And, what should be the MEANS of sending this info? ARE SOME OF TOPIC WE WILL BE EXPLORING DURING THE COURSE OF OUR STUDY DATA COMMUNICATION o When we communicate , we share information o Information can be LOCAL or REMOTE o Between Individuals LOCAL communication occurs face to face o REMOTE communication occurs over a long distance o When we refer to COMPUTER SYSTEMS, Data is represented in the form of Binary Units (Bits) in the form of Zeros (0’s) and One’s (1’s) o Also the entities can most of the times be considered to be COMPUTERS Data Communication Definition (Modified) Therefore, our earlier definition can easily be modified to: “Data Communication is the exchange of data (in the form of 0’s and 1’s) between two devices (computers) via some form of the transmission medium.” LOCAL and REMOTE Data Communication LOCAL Data communication is considered to be local if the communicating devices are present in the same building or a similarly restricted geographical area © Copyright Virtual University of Pakistan 5 CS601-Data Communication VU REMOTE Data Communication is considered remote, if the devices are farther apart. VAGUE DEFINITIONS We will clarify Data Communication System For Data Communication to occur, the communicating devices must be a part of a communication system made up of some specific kind of hardware and software This type of a system is known as a “DATA COMMUNICATION SYSTEM” Effectiveness of Data Comm. System Effectiveness depends upon three fundamental characteristics: ¾ Delivery ¾ Accuracy ¾ Timeliness (Better NEVER than LATE) 9 Example of the POSTAL MAIL Components of Data Comm. Systems Components of Data Com Systems Any system is made up of more than one component. Similarly, a data communication system is made up of 5 components as shown in the fig: ¾ Message ¾ Sender ¾ Receiver ¾ Medium ¾ Protocol © Copyright Virtual University of Pakistan 6 CS601-Data Communication VU MESSAGE ¾ Information or Data to be communicated ation of these Data Communication Messages 9 Files ¾ Can be text, numbers, video or any combin ¾ In short anything that can be represented using binary bits (meaningful collections of records) 9 Data/information requests (database queries, Web page requests, 9 nses etc.) Respo to requests and commands or error messages 9 Status messages (about the network’s functional status) 9 Control messages transmitted between network devices to control 9 e network traffic Correspondenc among network users MESSAGE TYPES ¾ Device that sends the data message ideo camera etc ght not be in the RECEIVER ¾ Device that receives the message elevision etc n medium may not be in a proper form to be supplied to the receiver and it must be processed SENDER SENDER ¾ Can be a Computer , Workstation, V ¾ As already discussed, the data from the sender mi appropriate format for the transmission medium and will need to be processed ¾ Can be a computer, workstation, T ¾ At times, the data received from the transmissio © Copyright Virtual University of Pakistan 7 CS601-Data Communication VU MEDIU ¾ Physical path that a message uses to travel from the Sender to the iver ¾ Can be a Copper Cable (Telephone), Coaxial Cable (Cable TV), ¾ see that Data needs to be transferred in the form of M Rece Fiber Optic Cable, LASERS or Radio Waves (Wireless Medium) We will ELECTROMAGNETIC signals and The Transmission Medium should be capable of carrying these EM Signals ¾ Transmission Media Transmission Media Medium Speed Cost Tw re isted Wi 300bps-10Mbps Low Microwave 256Kbps-100Mbps Low Coaxial Cable 56Kbps-200Mbps Low Fiber Optic Cable 500Kbps-10Gbps High PROTOCOL ¾ Set of Rules Governing Communication nts an Agreement between communication devices ¾ Without Protocol, two devices may be connected but they will not can only communicate provided they both speak the same language. A little ¾ Represe be able to communicate 9 EXAMPLE: Consider the communication between two individuals. They more complex Comm. System © Copyright Virtual University of Pakistan 8 CS601-Data Communication VU EXAMPLE – ELECTRONIC MAIL Explanation In Terms of a little more complex Comm. System SENDER SIDE ¾ Input device and transmitter are components of a Personal Computer ¾ User of a PC wishes to send a message ‘m’ ¾ User activates electronic mail package e.g. hotmail ¾ Enters the message via input device (keyboard) ¾ Character string is buffered in main memory as a sequence of bits ‘g’ ¾ PC is connected to some trans system such as a Telephone Network via an I/O Transmitter like Modem ¾ Transmitter converts incoming stream ‘g’ into a signal ‘s’ RECEIVER SIDE ¾ The transmitted signal ‘s’ is subject to a number of impairments depending upon the medium ¾ Therefore, received signal ‘r’ may differ from ‘s’. ¾ Receiver attempts to estimate original ‘s’ based on its knowledge of the medium and received signal ‘r’ ¾ Receiver produces a bit stream g’(t) ¾ Briefly buffered in the memory ¾ Data is presented to the user via an output device like printer, screen etc. © Copyright Virtual University of Pakistan 9 CS601-Data Communication VU ¾ The data viewed by user m’ uploads/Litterature/ handouts-data-comm.pdf