![7
Text Book
• Larry L. Peterson and Bruce S. Davies,
Computer Networks: A Systems Approach
– Third Edition [2003], Morgan Kaufmann
Publishers, San Mateo, California, USA](https://image.slidesharecdn.com/acnlecture1-241126185703-e91c540f/85/Advanced-Computer-Networks-Lecture-1-ppt-7-320.jpg)
Advanced Computer Networks Lecture 1.ppt
- 3. 3 Instructor’s introduction • Farhan Elahi Asst. Prof. Dept. of Computer Science FICT, BUITEMS, Quetta. You may download the lecture slides by using the following link. http://sites.google.com/site/farhanelahi/home/lecturers/acn
- 4. 4 Significance and Rationale of course • Networks and telecommunication is getting more and more importance • Future telecomm networks will be more oriented toward “networks” rather than “communication” • Widespread Internet, diffused in our daily life is a ground reality; its beneficial to understand it • Its fun to play with protocols (software) and able to design exciting new type of networks
- 5. 5 Foundation Course in Network Stream • This Computer Networks course is a foundation course for “Networks” as the Area of Specialization • It is a required pre-requisite course for the following advanced level courses in networking – Performance Analysis of Communication Networks – Integrated Services over Packet Networks – Computer Network Security – Mobile Networking • It is a recommended pre-requisite for the course: – Network and System Programming
- 6. 6 Course Material • Reference books – Many textbooks on Networking may be consulted • Lot of research papers! – Many will be made available on course web site • RFCs and Internet drafts – Related to TCP/IP suite and other protocols • Web resources – Tutorials, white papers, reports, etc.
- 7. 7 Text Book • Larry L. Peterson and Bruce S. Davies, Computer Networks: A Systems Approach – Third Edition [2003], Morgan Kaufmann Publishers, San Mateo, California, USA
- 8. 8 Prerequisites • Required: • An undergraduate level course on computer networks • Good knowledge of C language, preferably in Unix/Linux – e.g. C and Data Structures course
- 9. 9 Course Evaluation • Assignments • Quizzes • Research Papers • Term Projects / Reports • Midterm exam • Final exam
- 10. 10 Expectations What do you want (or expect) to learn from this course ?
- 11. 11 Expectations • This course IS about … – Network principles and concepts – General purpose computer networks – Internet perspective • Major components of the Internet protocol suite – Network software – Designing and building a system
- 12. 12 Expectations • This course IS NOT about … – Survey of existing protocol standards – Specialized networks (e.g. CATV, telephone) – OSI perspective – Network hardware • Data transmission on physical layer – Queuing theory (we do survey, if time permits)
- 13. 13 Expectations We will learn why networks are like they are
- 14. 14 Objectives: Principles and Concepts • At the end of this course, you should be able to: – Identify the problems that arise in networked communication – Explain advantages/disadvantages of existing solutions to these problems in different networking scenarios – Evaluate novel approaches to these problems – Understand the components of Internet protocol suite – Understand the implications of a given solution for performance in various networking environments
- 15. 15 Objectives: Programming • At the end of this course, you should be able to: – Identify and describe the purpose of each component of the TCP/IP protocol suite – Develop client-server applications using TCP/IP – Understand the impact of trends in network hardware on network software issues
- 16. 16 Course Contents • Overview • Introduction to network programming • Direct link networks • Packet switching • Internetworking • End-to-end protocols • Congestion control and resource allocation • End-to-end data • Applications • Performance analysis and queuing theory (?)
- 17. 17 Introduction • Outline – Statistical Multiplexing – Inter-Process Communication – Performance Metrics – Network Architecture
- 18. 18 What is Your Over-ambitious Goal ? • Build a computer network which – Can grow to global proportions – Support diverse applications • Then … think about – Underlying building blocks • Which available technologies to use – Integrating the blocks to communicate • Which software architecture to use
- 19. Network Design Before looking inside a computer network, first agree on what a computer network is?
- 20. 20 Computer Network ? • Set of serial lines to attach terminals to mainframe ? • Telephone network carrying voice traffic ? • Cable network to disseminate video signals ? Specialized to handle: Keystrokes Voice Video
- 21. 21 What Distinguishes a Computer Network ? • Generality • Built from general purpose programmable hardware • Supports wide range of applications
- 22. 22 Applications – Users’ Contact with the Network • Most people know the Internet through its applications – Web, email, streaming audio and video, chat, … • Applications present an intuitively simple interface – Textual and graphical objects – Simple “clicks” to maneuver the application • However, users are not aware of what happens in the network with their simple “clicks” !!!
- 23. 23 Applications – Consumers of Networks • On a simple click, several messages may be exchanged over the Internet • In a web browser, 17 messages may be exchanged – up to six messages to translate the server name – three messages to set up a TCP connection – four messages to send HTTP “get” request + response – four messages to tear down the TCP connection • Moreover, millions of messages are exchanged each day by Internet nodes to make their presence and services known
- 24. 24 Applications – the Driving Force • Streaming audio and video is an emerging application – Source generates and sends the video stream in messages across the Internet • Video-on-demand: reads a preexisting movie – One-way data transfer • Videoconferencing: interactive session – Very tight timing constraints • Diversity of applications that can be built on top of the Internet hint at the complexity of the Internet design
- 25. 25 Our Road Map … • Fortunately, we are not the first to build a computer network • Lets start exploring the path that others have already dig deep • By asking (and answering) why networks are designed the way they are
- 26. 26 Network Overview • What must a network provide ? – Connectivity – Cost-effective sharing – Functionality – Performance • How are networks designed and built ? – Layering – Protocols – Standards
- 27. 27 Perspective • For network user – Connectivity: for services required; error free delivery within acceptable time limits • For network designer – Efficiency: cost-effective design, fair allocation and efficient use of resources • For network operator – Maintenance: easy to administer, fault localization & isolation, usage accounting
- 28. 28 Building Blocks • Nodes: PC, special-purpose hardware… – Hosts – Switches • Links: coax cable, optical fiber… – Point-to-point – Multiple access …
- 29. 29 Why not connect each node with every other node ? • Number of computers that can be connected becomes very limited • Number of wires coming out of each node becomes unmanageable • Amount of physical hardware/devices required becomes very expensive • Solution: indirect connectivity using intermediate data forwarding nodes
- 30. 30 Switched Networks – Two or more nodes connected by a link – Circular nodes (switches) implement the network – Squared nodes (hosts) use the network • A network can be defined recursively as...
- 31. 31 Switched Networks – Two or more networks connected by one or more nodes: internetworks – Circular nodes (router or gateway) interconnects the networks – A cloud denotes “any type of independent network” • A network can be defined recursively as...
- 32. 32 A Network A network can be defined recursively as Two or more nodes connected by a physical link OR Two or more networks connected by one or more nodes
- 33. 33 Components of a Network
- 34. 34 Switching Strategies • Circuit switching: carry bit streams a. establishes a dedicated circuit b. links reserved for use by communication channel c. send/receive bit stream at constant rate d. example: original telephone network • Packet switching: store- and-forward messages a. operates on discrete blocks of data b. utilizes resources dynamically according to traffic demand c. send/receive messages at variable rate d. example: Internet
- 35. 35 What next ? • Hosts are directly or indirectly connected to each other • Can we now provide host-host connectivity ? • Nodes must be able to say which host it wants to communicate with
- 36. 36 Addressing and Routing • Address: byte-string that identifies a node – Usually unique • Routing: forwarding decisions – Process of determining how to forward messages to the destination node based on its address • Types of addresses – unicast: node-specific – broadcast: all nodes on a network – multicast: some subset of nodes on a network
- 37. 37 Wrap-up • A network can be constructed from nesting of networks • An address is required for each node that is reachable on the network • Address is used to route messages toward appropriate destination