1 CS101 Introduction to Computing Lecture 28 Introduction 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 share information and other resources

4 Types of Computer Networks according to the network access policy Private Public

5 Types of Computer Networks according 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 Claims processing in Lahore 4/ 7

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

23 Key Question! Why process the insurance claim in Pakistan?

24 Answer: Everybody Wins! Tom Peters ACME Insurance Bhola eServices

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

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

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

28 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!

29 Internet : the enabler !

30 What else does the Internet enable ?

31 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

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

33 Internet Users Worldwide 673M in B+ in 2005 (48% wireless)

34 1.2M Internet users in Pakistan in 5/2000 (1% of population) In early 2002, 54% of Australian population 51% of Singaporean population 39% of Japanese population 3% of Chinese population

35 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

36 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

37 inter. net

38 Internet: Network of Networks 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

39 Internet ---- Web ?

40 Internet ---- Intranet ?

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

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

43 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

44 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)

45 Chronology of events that led to today’s Internet

's 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

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

's 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

'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

's : 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

's NSF awards a grant to Merit Network, Inc. to operate & manage future development of the NSFNET Merit collaborates with IBM & MCI on R&D for fast networking technologies The backbone network is upgraded to T1, making it able to transmit data at speeds of 1.5 Mb/s (approx. 60 pages of text/second)

's The ARPANET is dissolved Gopher is developed at the U of MN It provides a hierarchical, menu-based method for providing & locating info on the Internet CERN releases WWW, developed by Tim Berners-Lee It uses HTTP and hypertext, revolutionizing the way info is presented & accessed on Internet

's The NSFNET is upgraded to T3 (45 Mb/s or about 1800 pages/s) Web browsers Mosaic & Netscape Navigator are introduced Their GUI makes WWW & Internet more appealing to the general public NSFNET is replaced by a new architecture, called vBNS which utilizes regional networks and Network Access Points

54 A lot has happened since 1995

55 Who runs the Internet ? Who owns it ?

56 Today’s Goal: Introduction to the Internet We looked at the role Internet plays in today’s computing We reviewed some of the history and evolution of the Internet

57 Next Lecture: Internet Services We will try to familiarize ourselves with with some of the Internet services: –http (surfing, shopping, searching) – –ftp –News groups, message boards, forums –Instant messaging –Multimedia delivery