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CS101 Introduction to Computing Lecture 28 Introduction to the Internet

CS101 Introduction to Computing Lecture 28 Introduction to the Internet. During the Last Lecture (Computer Networks). We looked at the role of networks in computing We looked at several different types of networks We familiarized ourselves with networking topologies and protocols .

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CS101 Introduction to Computing Lecture 28 Introduction to the Internet

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  1. CS101 Introduction to ComputingLecture 28Introduction to the Internet

  2. During the Last Lecture(Computer Networks) • We looked at the role of networks in computing • We looked at several different types of networks • We familiarized ourselves with networking topologies and protocols

  3. Computer Network Multiple computers that are connected together to shareinformation and other resources

  4. Types of Computer Networksaccording to the network access policy • Private • Public

  5. Types of Computer Networksaccording to the distance between nodes • LAN: Local Area Network • WAN: Wide Area Network

  6. Network Topologies • The pattern in which computers are connected to form a network • Popular patterns: • Point-to-point • Star • Bus • Ring • Networks are also formed by combining 2 or more of these 4 basic patterns

  7. Networking Protocols • Networks use protocols, or rules, to exchange information through shared channels • These protocols prevent collisions of data caused by simultaneous transmission between two or more computers • Several protocols are available for various types of networks. Here we discuss two that are popular for LANs: Ethernet; Token Ring

  8. Types of Communication Channels • Wire • Wireless

  9. Wireless (Radio) LANs Are Becoming Popular Key benefits: • Set-up time • Set-up cost • Maintenance cost • Cost • Key challenges: • Security & privacy • Quality of service • Cost

  10. Today’s Goal:Introduction to the Internet • To become able to appreciate the role of the Internet in today’s computing • To become familiar with the history and evolution of the Internet

  11. an accident!

  12. This car was involved in that accident

  13. It belongs to … Mr. Tom Peters of Palo Alto, California

  14. After the accident, Mr. Peters … filled out a form, giving info about: • Himself • The circumstances of the accident • Estimated repair expenses & then …

  15. 1/7 Mr. Peters’s fax machine

  16. 2/7 ACME Insurance Group’s server in New York

  17. 3/7 Bhola eServices (Pvt) Ltd’s server at Davis Rd,Lahore

  18. 4/7 Claims processing inLahore

  19. 5/7 Bhola eServices (Pvt) Ltd’s server at Davis Rd,Lahore

  20. 6/7 ACME Insurance Group’s server in New York

  21. 7/7 Mr. Peters’s home PC

  22. Key Question! Why process the insurance claim in Pakistan?

  23. Answer: Everybody Wins! • Tom Peters • ACME Insurance • Bhola eServices

  24. Answer: Everybody Wins! • Tom Peters • ACME Insurance • Bhola eServices Lower premium & Quicker turnaround

  25. Answer: Everybody Wins! • Tom Peters • ACME Insurance • Bhola eServices Better margins due to 50% saving on claim processing costs

  26. Answer: Everybody Wins! • Tom Peters • ACME Insurance • Bhola eServices Internal rate of return (IRR) of 60-80%

  27. The Key Point … Bhola eServices (Pvt) Ltd is … … supplying a service … using local, attractively-priced workers … to a remote, overseas client … over the Internet … & making good money in the process!

  28. Internet: the enabler!

  29. What else does the Internet enable?

  30. What Else? • Enables users located at far-way locations to easily share information with others located all over the world • Enables users to easily and inexpensively communicate with others located all over the world • Enables the users to operate and run programs on computers located all over the world

  31. The Internet is unlike any previous human invention. It is a world-wide resource, accessible to all of the humankind.

  32. Internet Users Worldwide 673M in 20021B+ in 2005(48% wireless)

  33. 1.2M Internet users in Pakistan in 5/2000(1% of population)In early 2002,54% of Australian population51% of Singaporean population39% of Japanese population3% of Chinese population

  34. Key Characteristics (1) Geographic Distribution Global - reaches around the world Robust Architecture Adapts to damage and error Speed Data can travels at near ‘c’ on copper, fiber, airwaves

  35. Key Characteristics (2) Universal Access Same functionality to everyone Growth Rate The fastest growing technology ever Freedom of Speech Promotes freedom of speech The Digital Advantage Is digital: can correct errors

  36. inter.net

  37. A large number of networks, interconnected physically • Capable of communicating and sharing data with each other • From the user’s point view, Internet – a collection of interconnected networks – looks like a single, unified network Internet: Network of Networks

  38. ? Internet ---- Web

  39. ? Internet ---- Intranet

  40. Internet Networking Protocols Communications on the Internet is controlled by a set of two protocols: TCP and IP

  41. TCP/IP (1)Transmission Control Protocol/Internet Protocol • Networking protocol used by allcomputers and networks on the Internet • Originally developed by the US DoD for Unix, but now available for most other OSes

  42. TCP/IP (2)Transmission Control Protocol/Internet Protocol • TCP breaks down the message to be sent over the Internet into packets • IP routes these packets through the Internet to get them to their destination • When the packets reach the destination computer, TCP reassembles them into the original message

  43. Tools & Services Available on the Internet • Electronic mail (POP, IMAP, SMTP) • Instant messaging (ICQ, MSN) • Remote login (telnet) • File transfer (ftp) • Network news (nntp) • WWW (http)

  44. Chronology of events that led to today’s Internet

  45. 1960's 1969 - DoD-ARPA creates an experimental network – ARPANET – as a test-bed for emerging networking technologies ARPANET originally connected 4 universities & enabled scientists to share info & resources across long distances ARPANET continued to expand throughout the 70's and 80's

  46. 1970's Networking tools developed in the 70's include: 1972 - The National Center for Supercomputing Apps. (NCSA) develops the telnet application for remote login, making it easier to connect to a remote computer 1973 - FTP (File Transfer Protocol) is introduced, standardizing the transfer of files between networked computers

  47. 1980's 1983 - The TCP/IP protocols becomes the only set of protocols used on the ARPANET This sets a standard for all networks, and generates the use of the term Internet as the net of nets ARPANET splits into two nets to keep military & non-military network sites separate: ARPANET and MILNET

  48. 1980's In 1982 and 1983, the first desktop computers begin to appear Many are equipped with an OS called Berkeley Unix, which includes networking SW, allowing easy connection to the Internet using telnet The PC revolution continues through the 80’s, making access to computer resources & net-worked info increasingly available to public

  49. 1980's 1985-86:NSF connects the US’s six supercomputing centers together, calling it the the NSFNET, or NSFNET backbone To expand access to the Internet, NSF developed regional nets, which were then connected to the NSFNET backbone Plus, NSF supported institutions (universities, etc.) in their efforts to connect to the regional nets

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