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COSC1078 Introduction to Information Technology Lecture 20 Internet

James Harland james.harland@rmit.edu.au. COSC1078 Introduction to Information Technology Lecture 20 Internet. James Harland james.harland@rmit.edu.au. COSC1078 Introduction to Information Technology Lecture 20 Internet. Introduction. James Harland Email: james.harland@rmit.edu.au

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COSC1078 Introduction to Information Technology Lecture 20 Internet

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  1. Intro to IT James Harland james.harland@rmit.edu.au COSC1078 Introduction to Information TechnologyLecture 20Internet

  2. Intro to IT James Harland james.harland@rmit.edu.au COSC1078 Introduction to Information TechnologyLecture 20Internet

  3. Intro to IT Introduction • James Harland • Email:james.harland@rmit.edu.au • URL:www.cs.rmit.edu.au/~jah • Phone:9925 2045 • Office:14.10.1 • Consultation:Mon 4.30-5.30, • Thu 11.30-12.30 • Who am I? And where do you find me?

  4. Intro to IT Introduction to IT 1 Introduction 2Images 3Audio 4Video WebLearnTest 1 5 Binary Representation Assignment 1 6 Data Storage 7Machine Processing 8 Operating Systems WebLearn Test 2 9 Processes Assignment 2 10 Internet 11Internet Security WebLearn Test 3 12Future of IT Assignment 3, Peer and Self Assessment

  5. Intro to IT Overview • Questions? • Assignment 3 • Peer and Self Assessment • Internet • Questions?

  6. Assignment 2 Some initial comments Some people have submitted .docx files. This will be penalised. Some people have not included blogs on Blackboard. This will be penalised. Some people have worked individually without permission. Guess what will happen …. Lecture 20: Internet Intro to IT

  7. Assignment 3 Reflect Answer reflection questions from tutorials See last lecture for ideas Research Write about a particular IT topic of your choice (5-6 paragraphs) electronic voting, information security, 3D user interfaces, digital music, digital video, electronic commerce, natural language processing, DNA computing, quantum computing, cryptography, malware detection and removal, Moore's Law, green computing, … Lecture 20: Internet Intro to IT

  8. SE Fundamentals Self and Peer Assessment • How well has each person contributed to the group? • Evaluated over the entire semester • Assessed on process, not product • Work out a grade for each person (CR, DI etc) • Then convert this to a mark out of 20 • Submit list of marks to tutor with justifications • Repeat previous step until the tutor is satisfied • See guidelines in Blackboard material

  9. Intro to IT Communications Developments ????: Writing 1440:Printing press 1844: Telegraph 1877: Telephone 1919:Radio 1928:Television 1969:ARPANET (Advanced Research Projects Agency) 1970's:Internet Protocol (IP) 1984:Domain names (.com, .org, etc) 1991: World Wide Web

  10. Intro to IT Number of Internet Hosts

  11. Internet Originally designed to survive nuclear war Grew out of army research into missile communication Key role in breaking down the Berlin Wall Lecture 20: Internet Intro to IT

  12. Intro to IT Internet • Dedicated channel: • two nodes exclusively use a single channel • works like traditional telephone • Packet switching: • break data down into packets • send packets from many users along link • can exploit redundancies and variations in network

  13. Intro to IT Protocols • Transmission Control Protocol (TCP): • basic necessities for data transfer • connection-oriented • Internet Protocol (IP): • data-oriented • necessary for packet-switched network “Should run on two tin cans and a string” There is an implementation for carrier pigeons ...

  14. Intro to IT Protocols

  15. Intro to IT Application Protocols • Define messages sent and data formats used • Generally known by user • Examples include HTTP, HTTPS, FTP, etc. Often specified in resource identifiers http://www.mysite.com:8080/info/mypage.html http://www.mysite.com:8080/info/mypage.html http://www.mysite.com:8080/info/mypage.html http://www.mysite.com:8080/info/mypage.html

  16. Intro to IT World Wide Web (WWW) • Combination of 4 different ideas: • Hypertext: information format for moving documents around • Markup Language: codes embedded in text indicating structure and presentation meaning • Resource Identifiers (URI, URL, ...) • Client-server model: client software requests resources from servers • Note WWW is not the Internet … 

  17. Intro to IT Internet Uses • File transfer & remote services • Email • Instant messaging • Web browsing • Peer to peer (P2P) • Telephony • Streaming media • “Web 2.0” • ....

  18. Internet Hi Dad! Listen! Hi Dad! Listen! Lisa? Lisa? Lecture 19: Internet: Images Intro to IT

  19. Internet Structure 2 1 3 4 Application Mordor sucks! Mordor sucks! Application 1Mor 2dor 1Mor 2dor Transport Transport 3suc 4ks! 3suc 4ks! 1 2 3 4 Network 3 1 Network 2 4 9 5 6 2 9 5 6 2 Link Link 3 2 4 1 Lecture 20: Internet Intro to IT

  20. Internet Structure 1 1Mor 6 6 Lecture 20: Internet Intro to IT

  21. Network Layer (Internet Protocol) Real intelligence is in the network layer Adds next destination to packet Not complete list of addresses Sends to next destination Retrieves final destination packets for this node Passes them to the transport layer Routing tables can be updated when disconnections occur Hop counts used to stop endless looping Lecture 20: Internet Intro to IT

  22. Transport layer Transmission Control Protocol (TCP) often used User Datagram Protocol (UDP) becoming more common TCP Establishes connection first Send and wait for acknowledgement Reliable Can adjust flow control to avoid congestion Often best for email (which is not real-time) Older Lecture 20: Internet Intro to IT

  23. Transport layer UDP Doesn’t establish connection Just sends and forget Efficient No congestion adjustment Works well for DNS lookup Often used for Voice over Internet Protocol (VoIP) applications such as Skype Lecture 20: Internet Intro to IT

  24. Internet addresses Unique 32-bit identifier (up to 4,294,967,296) Soon to become 128-bit identifier Managed by Internet Corporation for Assigned Names and Numbers (ICANN) ISPs get “blocks” of addresses 32-bit string represented as N1.N2.N3.N4 where Ni is in the range 0..255 17.12.25.0 means 00010001000011000001100100000000 Lecture 20: Internet Intro to IT

  25. Internet addresses Dotted decimal notation is still not very kind to humans … www.sludgefacethemovie.com -> ??.??.??.?? Translation done by name servers which look up the Domain Name System (DNS) Domains such as rmit.edu.au can be structured by the domain owner (eg goanna.cs.rmit.edu.au) Lecture 20: Internet Intro to IT

  26. IPv4 vs IPv6 Internet Protocol version 4 (used since 1981) 32-bit addresses Can handle “only’’ 4,294,967,296 unique addresses Exhausted in February 2011 IPv6 uses 128-bit addresses IPv6 can handle “only” 3.4×1038addresses IPv5 didn’t change the IPv4 address space and wasn’t successful for other reasons … Lecture 20: Internet Intro to IT

  27. Intro to IT Conclusion • Work on Assignment 3 • Name 5 people who are unaffected by the Internet …

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