1. Data Communications

2. Data Communications A. Overview • Introduction • Network Models B. PHYSICAL LAYER AND MEDIA • Data and Signals • Digital Transmission • Analog Transmission • Bandwidth Utilization : Multiplexing and Spreading • Transmission Media • Switching • Using Telephone and Cable Networks for Data Transmission • Error Detection and Correction

3. Data Communications C. DATA LINK LAYER • Data Link Control • Multiple Access • Wired LANs : Ethernet • Wireless LANs • Connecting LANs, Backbone Networks, and Virtual LANs • Wireless WANs: Cellular Telephone and Satellite Networks • SONETISDH • Virtual-Circuit Networks : Frame Relay and ATM D. General Mechanisations in Telecommunication Network E. Traffic Engineering in Telecommunication Networks

4. Literature • Behrouz A. Forouzan, Data Communications and Networking 4th ed. • Tanenbaum A.S, Computer Networks, Prentice Hall Edition • Proakis, J.G, Digital Communications, Mc. Graw-Hill International

5. Other Sources • Interactive Webmuseum http://webmuseum.mi.fh-offenburg.de • Computer Netze (auf Deutsch) http://mi-learning.mi.fh-offenburg.de/CNetze/

6. Courses • 3 Credits (SKS) • Course Friday 11.00 – 14.00 • Labs • Examination • Quizz + Presentation + QA (70%) • Final Examination (70%) • Labs (30%) • Grade E < 30% • List of Attendance

7. INTRODUCTION

8. 1.1 DATA COMMUNICATION The term 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.

9. Five Components of Data Communication

10. Data flow (simplex, half-duplex, and full-duplex)

11. 1.2 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.

12. Types of connections: point-to-point and multipoint

13. Categories of Topology

14. A fully connected mesh topology (five devices)

15. A star topology connecting four stations

16. A bus topology connecting three stations

17. A ring topology connecting six stations

18. A hybrid topology: a star backbone with three bus networks

19. An isolated LAN connecting 12 computers to a hub in a closet

20. WANs: a switched WAN and a point-to-point WAN

21. A heterogeneous network made of four WANs and two LANs

22. 1.3 THE INTERNET The Internet has revolutionized many aspects of our daily lives. It has affected the way we do business as well as the way we spend our leisure time. The Internet is a communication system that has brought a wealth of information to our fingertips and organized it for our use.

23. Hierarchical organization of the Internet

24. 1.4 PROTOCOLS AND STANDARDS In this section, we define two widely used terms: protocols and standards. First, we define protocol, which is synonymous with rule. Then we discuss standards, which are agreed-upon rules.

25. Protocoll • Syntax • Semantics • Timing

26. Standards • De facto • Standards that have not been approved by an organized body but have been adopted as standards through widespread use are de facto standards. De facto standards are often established originally by manufacturers who seek to define the functionality of a new product or technology. • De jure • Those standards that have been legislated by an officially recognized body are de jure standards.

27. Telecommunication Standarization • Worldwide • ISO (International Standard Organization) • IEC (International Electrotechnical Commission) • ITU (International Telecommunication Union) • IEEE (Institute of Electrical and Electronic Engineering) • Europe • CEPT (Conference of European Postal and Telecommunication Administration) • ETSI (European Telecommunications Standard Institute) • North America • ANSI (American Narional • Germany • DIN (Deutsches Institute fuerNormung) • BAPT (Bundesamtfuer Post und Telecommunication