Lecture 1- Data Comm-final.pdf

Lecture (1) " Data Communication“ Chapter 1: Networking Fundamentals Presented by : Dr. Nehal El Azaly Course Information Lecturers: Prof. Osama Elnahas –Dr. Nehal Elazaly -Dr. Dina Abdelhafiz Credit hours (2) Requirements & Grading (Total 100 marks) – Class work and attendance (3...

Lecture (1) " Data Communication“ Chapter 1: Networking Fundamentals Presented by : Dr. Nehal El Azaly Course Information Lecturers: Prof. Osama Elnahas –Dr. Nehal Elazaly -Dr. Dina Abdelhafiz Credit hours (2) Requirements & Grading (Total 100 marks) – Class work and attendance (30 marks) – Midterm exam (20 marks) – Final Exam during finals week (50 marks) Textbook: Data Communications and Networking | 5th Edition: Behrouz Forouzan  Data & Information Data refers to the facts that are collected while information refers to processed data that enables us to take decisions. Ex. When result of a particular test is declared it contains data of all students, when you find the marks you have scored you have the information that lets you know whether you have passed or failed. Data Communications The term of telecommunication means communication at a distance. The word data refers to information presented in whatever form is agreed upon by the parties creating and using the data. Data communications are the exchange of data between two devices via some form of transmission medium such as a wire cable. Data Communications The effectiveness of any data communications system depends upon the following four fundamental characteristics: 1.Delivery 2. accuracy 3. timeline 4. jitter  Characteristics of Data Communication 1. Delivery: The data should be delivered to the correct destination and correct user. 2. Accuracy: The communication system should deliver the data accurately, without introducing any errors. The data may get corrupted during transmission affecting the accuracy of the delivered data. 3. Timeliness: Audio and Video data has to be delivered in a timely manner without any delay; such a data delivery is called real time transmission of data. 4. Jitter: It is the variation in the packet arrival time. Uneven Jitter may affect the timeliness of data being transmitted. Introduction of Data Communication Components of Data Communication system 1- Sender 2- Receiver 3- Message (Data that is sent between the sender and receiver) 4- Protocols (Set of rules that control the communication) 5-Medium (Transmission medium either wired or wireless) Data Representation There may be different forms in which data may be represented. 1. Text 2. Numbers 3. Images 4. Audio 5. Video Data Flow of Data Communication 1- Simplex (One direction-sending or receiving) 2- Half-duplex (sending and receiving but not at same time) 3-Full-duplex (sending and receiving at the same time)  Networks A network is a set of devices (often referred to as nodes) connected by communication links. A node can be a computer, printer, or any other device capable of sending and/or receiving data generated by other nodes on the network. Network Criteria A Compute network should ensure – reliability of the data communication process – security of the data – performance by achieving higher throughput and smaller delay times Types of connection Categories of Netwoks Networks are categorized on the basis of their size. The three basic categories of computer networks are: A. Local Area Networks (LAN) B. Wide Area Network (WAN) C. Metropolitan Area Network (MAN)  Introduction of Data Communication A. Local Area Networks (LAN) – is usually limited to a few kilometers of area. It may be privately owned and could be a network inside an office on one of the floor of a building – LAN could be a network consisting of the computers in a entire building. B. Wide Area Network (WAN) – is made of all the networks in a (geographically) large area. – The network in the entire state like Egypt could be a WAN C. Metropolitan Area Network (MAN) – is of size between LAN & WAN. It is larger than LAN but smaller than WAN. – It may comprise the entire network in a city like Alexandria. Protocol For successful communication to occur, the sender and receiver must agree upon certain rules called protocol. A Protocol is defined as a set of rules that governs data communications. A protocol defines what is to be communicated, how it is to be communicated and when it is to be communicated. 17/ 17