-Lec-1_Intro_to_data_com_

DATA COMMUNICATION : 

DATA COMMUNICATION Lecture-1

Course Outline : 

The course will consist of : 32 lectures 5-10 assignments 4 exams (3 midterm and 1 final) Grading Criteria: Two Best Midterm:40% Final Exam: 40% Assignments: 20% Course Outline

Textbook : 

“Data Communications and Networking” 4th Edition by Behrouz A. Forouzan “Data and Computer Communication” 6th Edition by William Stallings Textbook

Overview of Lecture 1 : 

Data Communication Brief History of Communication Data Communication System Overview of Lecture 1

DATA COMMUNICATION : 

“Data Communication is the exchange of Information from one entity to the other using a Transmission Medium” DATA COMMUNICATION

History : 

History Telegraph 1837 Samuel Morse This led to building a telecommunication infrastructure of poles and wires as well as the development of communication hardware and protocols. Telephone 1876 Alexander Graham Bell Invention of Telephone and wireless communication system by guglielmo Marconi in 1890s set the stage for today's communication industry. By 1950’s By 1950 Telephone and telegraph companies had developed a network of communication facilities throughout the industrialized world.

History (Cont.) : 

1970’S Although development of databases, languages, operating systems and hardware from 1950 to 1970, large scale data communication systems did not emerge until the 1970s. This was stimulated by three major development Large scale integration of circuit reduced cost and size of terminals and communication system. New software systems that facilitated the development of data communication networks. Competition among providers of transmission facilities reduced the cost data circuits. Today History (Cont.)

Data Communication Definition (Modified) : 

Data Communication Definition (Modified) “Simply means sharing of data locally or remotely.” “Exchange of data between two devices via some form of Transmission medium such as wire.” “Exchange of data (in form of 0’s and 1’s) between two devices (e.g. computers) via some form of the transmission medium.” Subset of Telecommunication in which Digital Communication Occurs (0’s & 1’s).

LOCAL and REMOTE Communication : 

LOCAL and REMOTE Communication LOCAL Communicating devices are present in the same building or a similarly restricted geographical area. REMOTE Communicating devices are present farther apart.

Data Communication System : 

Data Communication System For Data Communication to occur, communicating devices must be a part of a system made up of some specific kind of hardware and software. This system is known as “DATA COMMUNICATION SYSTEM”

Effectiveness of Data Comm. System : 

Effectiveness depends upon three fundamental characteristics: Delivery (to the specific destination) Accuracy (correctly) Timeliness “Better late than never”, “Better never than late”. Jitter (uneven delay in the delivery of audio or video packets) For example a postal mail. Effectiveness of Data Comm. System

Components of a Simple Data Communication System : 

Components of a Simple Data Communication System

Components of a Data Communication System : 

A Data communication system is made up of 5 components: Message Sender Receiver Medium Protocol Components of a Data Communication System

Message : 

The message is the information (data) to be communicated. A message is transmitted from sender to receiver. It can data file an audio or video file or any text message “A message also keeps information like sender and destination addresses.” Message

Sender : 

It is also called “source”. It is the device which generates the message and responsible for its transmission. It can be a computer Workstation telephone handset video camera or any communication device. Sender

Receiver : 

It is also called “destination/sink”. It is the device that receives the transmitted message. It may be a computer Workstation telephone handset Television or any communication device. Receiver

Medium : 

The transmission medium is the physical path by which a message travels from sender to receiver. It may be a guided medium coaxial cable twisted pair cable fiber optic unguided medium electro-magnetic waves micro waves infrared waves Medium

Transmission Media : 

Transmission Media

Protocol : 

Protocols are also called language of communication. A protocol is a set of rules that governs data communication. Both sender & receiver must have the same protocol for communication. It represents an agreement between the communicating devices. Without a protocol, two devices may be connected but not communicating, just as a person speaking French cannot be understood by a person who speaks only Japanese. Protocol

A Complex Data Comm. System : 

A Complex Data Comm. System

Components of a Data Communication System : 

Source generates data to be transmitted Transmitter Converts data into transmittable signals Transmission System Carries data Receiver Converts received signal into data Destination Takes incoming data Components of a Data Communication System

EXAMPLE – Electronic Mail : 

EXAMPLE – Electronic Mail

An Actual Digital Data Communication System : 

An Actual Digital Data Communication System

Summary : 

Data Communication Brief History of Communication Data Communication System Summary

Suggested Reading : 

Section 1.1, “Data Communications and Networking” 4th Edition by Behrouz A. Forouzan Sections 1.1, 1.2, “Data and Computer Communication” 6th Edition by William Stallings Suggested Reading