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G64INC
Introduction to Computer Communications
Ho Sooi Hock
Introduction
• Administration matters
• Overview of
– module goals
– assessments & support
• Brief overview of contents
• Basic concepts of some key ideas and
issues of networking
Objectives
• Understand the basic principles of data
communications and computer networks
• Appreciate the complex trade-offs that are inherent
in the design of networks
• Provide a guided tour of network technologies from
the lowest levels of data transmission up to network
applications
• Learn about the current and de facto networking
standards, i.e. internet protocols
Assessment Structure
• 100% exam – 2 hr written paper
• No coursework/laboratory
• Style of question will be similar to past
exams, samples of which can be accessed
online
• Easy if you understand the underlying
concepts well
References and Notes
• Notes are available online at:
– http://sepang.nottingham.edu.my/G64INC/ or
http://moodle.nottingham.ac.uk
• The core recommended course text is:
– Computer Networks and Internets by Douglas E.
Comer, 5th Edition, Prentice Hall
• Supplementary texts are:
– Computer Networks by Tannenbaum, 5th Edition,
Prentice Hall
– Data Communications and Networking by
Forouzan, 5th Edition, McGraw-Hill
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
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Accessing/Sharing remote resources
Communication and Collaboration
Mobility and Ubiquity
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) vs Wide Area
Netwoks (WANs)
• By connectivity
– Point to Point vs Broadcasting Networks
• By communication medium
• By access/usage
– Fixed vs Mobile
Size – Differences between Local and Wide
Area Networks
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‘Speed’ – bandwidth and latency
Management
Security
Reliability
Billing
Heterogeneity (and standards)
Connectivity
• Point to Point Networks
– Star
– Tree
– Mesh
– Irregular
• Broadcast Networks
– Satellite/radio
– Bus
– Ring
Communication Medium
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‘Speed’ – bandwidth and latency
Range
Sharing
Topology
Installation and maintenance costs
Reliability
Access/Usage
• Mobile networking has emerged in the last decade.
Some new issues arising are:
– location and tracking
– semi-persistent connections
– complex administration and billing as devices and users
move around the network
Common Issues in Networking
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Addressing
Routing
Framing and Encoding
Error Detection and Correction
Flow and Congestion Control
Module Contents and Structure
• Part 1: Data Transmission
• Part 2: Packet Transmission
– Local Area Networks
– Wide Area Networks
• Part 3: Internetworking
• Part 4: Applications
Part 1: Data Transmission
– Transmission media
– Local asynchronous communication (RS-232)
– Long distance communication (modems and
carriers)
» by Dr Abdul Raib
Part 2: Packet Transmission
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Packets, frames and error detection
Local Area Networks (LANs)
Hardware addressing
LAN wiring and physical topology
Extending LANs: fibre modems, repeaters, bridges and
switches
» by Dr Abdul Rakib
– WAN technologies and routing
– Network ownership and service paradigm
– Protocols and layering
» by Ho Sooi Hock
Part 3: Internetworking
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Concepts, architecture and protocols
IP addresses
Binding protocol addresses (ARP)
IP datagrams and datagram forwarding
IP encapsulations, fragmentation and reassembly
Future of IP
TCP (reliable transport service)
» by Ho Sooi Hock
Part 4: Applications
– Client-server interactions
– The socket interface
– Example applications
» by Ho Sooi Hock
Acknowledgements
Most lecture slides used
in this presentation
are adapted from the same module
taught in
Nottingham, UK campus