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G52CCN Computer Communications and Networks. Milena Radenkovic Room: B47 Email: mvr@cs.nott.ac.uk. Introduction. Practical matters Module goals, structure and contents Initial introduction to some key ideas and issues. Lectures. Thursday 15:00 – 16:00
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G52CCNComputer Communications and Networks Milena Radenkovic Room: B47 Email: mvr@cs.nott.ac.uk
Introduction • Practical matters • Module goals, structure and contents • Initial introduction to some key ideas and issues
Lectures • Thursday 15:00 – 16:00 • Jubilee Campus, Exchange Building, LT2 • Friday 09:00 – 10:00 • Jubilee Campus, Exchange Building, LT2
Related modules • G53ACC - Advanced Computer Communications • G5BIAW - The Internet and the World Wide Web
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.
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
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
What is a computer network? • An interconnection of autonomous computers (as opposed to communication between separate but interdependent parts of a single computer)
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
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
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
Size - differences between local and wide area networks • ‘Speed’ - bandwidth and latency • Management • Security • Reliability • Billing • Heterogeneity (and standards)
Connectivity - point to point networks tree star irregular mesh
Connectivity - broadcast networks wire satellite/radio
Medium - differences between communication media • ‘Speed’ - bandwidth and latency • Range • Sharing • Topology • Installation and maintenance costs • Reliability
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
Common issues in networking • Addressing • Routing • Framing and encoding • Error detection and correction • Flow and congestion
Module contents and structure Part 4: applications Part 3: internetworking Part 2: packet transmission Part 1: data transmission
Part 1: data transmission • Transmission media; • Local asynchronous communication (RS-232); • Long distance communication (modems and carriers)
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
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)
Part 4: Applications and Security • Client-server interaction • The socket interface • Example applications
Next Lecture: • Local Ansynchronous Communication and RS-232