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Internet and Intranet Protocols and Applications

Internet and Intranet Protocols and Applications. Lecture 1: Introduction January 21, 1999 Arthur P. Goldberg Clinical Associate Professor of Computer Science New York University artg@cs.nyu.edu. Why Study “Internet and Intranet Protocols and Applications”?.

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Internet and Intranet Protocols and Applications

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  1. Internet and Intranet Protocols and Applications Lecture 1: Introduction January 21, 1999 Arthur P. Goldberg Clinical Associate Professor of Computer Science New York University artg@cs.nyu.edu

  2. Why Study “Internet and Intranet Protocols and Applications”? • Same systems used in the two major types of networks, the public Internet and internal (corporate) Intranets • Widely used, and becoming more so rapidly • Accessible for study, because protocol standards are published and their design is publicly debated

  3. Growth of the Internet “New survey” “Old survey” Source: Network Wizards; available at http://www.nw.com/zone/host-count-history, Jan 1997

  4. Growth of the Internet Source: Internet Domain Survey, July 1998, Network Wizards; http://www.nw.com/zone/WWW/report.html, Jan 1997 and Kleinrock, Queueing Systems, Vol 2: Computer Applications, pp. 305-308

  5. Growth of the Internet Source: Network Wizards; available at http://www.nw.com/zone/summary-reports/report-9707.doc, July 1997

  6. Growth of the Web Source: WebCrawler; WAS available at http://webcrawler.com/WebCrawler/Facts/Size.html, in Jan 1997

  7. Why Study “Internet and Intranet Protocols and Applications”? • Same systems used in the two major types of networks, the public Internet and internal (corporate) Intranets • Widely used, and becoming more so rapidly • Accessible for study, because design of protocol standards are publicly debated and published

  8. Things we design and build • Protocols • Client and server software (and intermediate systems, like caching proxies, gateways and firewalls) • Object formats for documents and programs (embedded in protocols)

  9. What do IIPAs do? • Share objects • Store, index, find objects • Transfer messages • Communicate securely • What don’t IIPAs do, typically? • Survive multiple application layer failures • Compute in parallel • Promise real-time performance

  10. Challenges • Heterogeneity • Client and server system architecture • Performance (in protocols and applications) • Interoperability (with existing protocols and applications) • End-user application design • Applications (Web sites and intranet systems - not a topic of this course)

  11. Highly Heterogeneous Computing Environment

  12. Other Heterogeneous Dimensions • OS • DOS … MVS • Architecture • x86 … CRAY • Spoken language • Legal entity

  13. The BSD Socket Interface • Partly integrated into existing I/O system calls • Servers • wait for a message to arrive • Clients • Initiate communications • Comer fig 5.4

  14. Tonight • Introduction • Growth of the Internet and intranets • Client/server systems • Review course • Syllabus • Textbooks and other readings, such as RFCs and papers • Assignments: homework, programming projects, take-home final • Layered protocol model of computer networks • Exponential growth in component performance / price

  15. We won’t study • Networking below the application layer (a prerequisite - you should be aware of routing, IP, TCP, UDP - but we’ll review for one week) • Programming languages (e.g. Java) - covered in Amsterdam’s “Programming for the WWW” • Writing HTML, cgi programs (you can learn this yourself) • Cryptographic protocol mathematics (important, but covered in “Privacy in Networks: Attacks & Defenses”, Rubin, Reiter & Kormann, T 5-7 402)

  16. Layered protocol model of computer networks • Application (We focus on activity here) • [Presentation] • [Session] • Transport • Network • Data • Physical

  17. Exponential Growth • Fundamental OBSERVED characteristic of two key areas of IT • Performance / Price of components - Gordon Moore’s ‘law’ • Market size and share • Like compound interest • x(y) @ x( y0 ) r ( y - y0) where r > 1

  18. Today • r @ Ö2, i.e.., doubling of performance / price every two years for a given price in • processors • memory (DRAM) • storage • disks, tapes, CD-ROMs • communications speeds • fiber, copper, microwave, spread spectrum

  19. Exponential Growth, e.g. • Transistors per chip • tpc @ x( y0 ) r ( y - y0) • y0 = 1972 • x( y0 ) = 1,500 • r = 2 1/2@ 1.41 • tpc @ 1500 x 1.41 ( y - 1972)

  20. Exponential Growth, Cont.

  21. Exponential Growth Dominates All Other • Consider • Exponential: xe = a r t • Linear: xl = b t • assume ( r > 1, a > 1, b > 1) • if (r t)/t > b/a • then xe > xl

  22. Moore, 1965 • “Complexity for minimum component costs has increased at a rate of roughly a factor of two per year. Over the longer term ... there is no reason to believe it will not remain nearly constant for 10 years.”

  23. Why ‘Moore’s law’? • Rising • Factory cost, factory output, market size • Stable • Cost per device ~= (total factory cost + design cost) / number of devices • Growing exponentially • Components per device • Thus, growing exponentially • Performance (proportional to components per device) / price

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