1. G52CCN Computer Communications and Networks Milena Radenkovic Room: B47 Email: mvr@cs.nott.ac.uk

2. Introduction Practical matters Module goals, structure and contents Initial introduction to some key ideas and issues

3. Lectures Thursday15:00 – 16:00 – Jubilee Campus, Exchange Building, LT2 Friday09:00 – 10:00 – Jubilee Campus, Exchange Building, LT2

4. Related modules G53ACC - Advanced Computer Communications G5BIAW - The Internet and the World Wide Web

5. Objectives To understand the basic principles of data communications and computer networks. To appreciate the complex trade-offs that are inherent in the design of networks. To provide a guided tour of network technologies from the lowest levels of data transmission up to network applications. To learn about current networking technologies, especially Internet protocols.

6. Assessment Two hour written examination The style of question will be based upon those from previous years. Their content will of course be different. Last year’s exam paper is on sale in the bookshop and previous papers are in the library. No coursework

7. Text books and notes My notes are available at: – http://www.cs.nott.ac.uk/~mvr/ccn The core recommended course text is: – Computer Networks and Internets, Douglas E. Comer, Prentice Hall Supplementary texts are: – Tannenbaum, Computer Networks, Prentice Hall – Halsall, Data and Computer Communications, Macmillan

8. What is a computer network? An interconnection of autonomous computers (as opposed to communication between separate but interdependent parts of a single computer)

9. Some goals of computer networks Access to remote resources Human communication Mobile computing Computing power through parallelism Optimising resources - load balancing Incremental growth of computer systems (reduced cost and risk) Increased robustness through graceful degradation

10. Uses of computer networks Email, World Wide Web, Video Conferencing, File Transfer, Collaborative Virtual Environments, Remote control of robots and machines, Dial up databases, Webcasting, Distributed Programs, Hacking, Banking, Internet telephone

11. Classifying networks By size – Local area networks (LANs) versus Wide area networks (WANs) By connectivity – Point to point versus broadcast networks By communication medium By mobility – Fixed versus mobile

12. Size - differences between local and wide area networks ‘Speed’ - bandwidth and latency Management Security Reliability Billing Heterogeneity (and standards)

13. Connectivity - point to point networks star tree irregular mesh

14. Connectivity - broadcast networks satellite/radio wire

15. Medium - differences between communication media ‘Speed’ - bandwidth and latency Range Sharing Topology Installation and maintenance costs Reliability

16. Mobility - issues arising in mobile networks Mobile networking has emerged in the last decade. Introduces new issues of: – energy efficiency – location and tracking – semi-persistent connections – complex administration and billing as devices and users move around the network

17. Common issues in networking Addressing Routing Framing and encoding Error detection and correction Flow and congestion

18. Module contents and structure Part 1: data transmission Part 2: packet transmission Part 3: internetworking Part 4: applications

19. Part 1: data transmission – Transmission media; – Local asynchronous communication (RS-232); – Long distance communication (modems and carriers)

20. Part 2: packet transmission – Packets, frames and error detection – Local area networks (LANs) – Hardware addressing – LAN wiring and physical topology – Extending LANS: Fiber Modems, repeaters, bridges and switches; – WAN Technologies and routing – Network ownership and service paradigm – Protocols and layering

21. Part 3: internetworking – Concepts, architecture and protocols – IP addresses – Binding protocol addresses (ARP) – IP Datagrams and datagram forwarding – IP encapsulations, fragmentation and reassembly – The future of IP – An error reporting mechanism (ICMP) – TCP (reliable transport service)

22. Part 4: Applications and Security – Client-server interaction – The socket interface – Example applications

23. Next Lecture: Local Ansynchronous Communication and RS- 232