The History and Technical Infrastructure of the Internet

1
EC427 Internet for Business Economists (IfBE)

• Lecture 2
• The History and Technical Infrastructure of the
  Internet

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Business Economists Guy Judge, September 2003
2
Todays objectives

• to inform you about the important stages in the
  development of the Internet, the applications
  that run on it and the associated protocols
• to familiarise you with some key points about the
  technical infrastructure of the Internet
• to highlight the role of some key people and
  organisations
• to look at the growth of the Internet and
  consider factors to account for this growth

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Business Economists Guy Judge, September 2003
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Reading

• Tanenbaum - especially Chapter 1
• Rohlfs Chapter 8
• the material on the IfBE website for week 2 and
  the links from it

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Business Economists Guy Judge, September 2003
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Follow up work for the week

• Practical 2
• 1 explanation of some key terms
• 2 identification of the role of some key people
• 3 identification of the role of some key
  organisations
• 4 Internet metrics issues

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Business Economists Guy Judge, September 2003
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Three points from last week

• the Internet and the World Wide Web are not the
  same thing
• the importance of protocols - the standards or
  set of rules that enable computers to communicate
  with each other
• the adaptable nature of the Internet and its
  institutions

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Business Economists Guy Judge, September 2003
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The Internet

• The Internet is an interconnected set of computer
  networks across the globe that work together
  under a common set of rules or protocols (the
  TCP/IP suite).

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Business Economists Guy Judge, September 2003
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World Wide Web (WWW)

• The World Wide Web is a collection of
• inter-linked documents and associated
• files that are made available to people
• with computers connected to the
• Internet via a special protocol called
• HTTP (HyperText Transfer protocol)

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Business Economists Guy Judge, September 2003
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Protocols

• A protocol is an agreement (set of rules)
  between the communicating parties (peers) on how
  communication is to proceed.

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The TCP/IP suite

• Q Why is it important?
• A It enables computers on different networks,
  designed by different vendors, to work together
  in delivering various applications e.g. e-mail,
  file transfer, remote login (telnet), etc.

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Business Economists Guy Judge, September 2003
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The TCP/IP reference model

• Application layer
• e.g. E-mail (SMTP), WWW (HTTP)
• Transport layer
• TCP
• Internet Layer
• IP - routing, packet switching
• Host to Network layer
• e.g. ISP or JANet

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Business Economists Guy Judge, September 2003
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TCP/IP key dates

• 1964 Paul Baran (RAND Corporation) publishes
  paper on packet-switching networks
• 1974 Vint Cerf and Bob Kahn publish paper
  describing TCP
• 1978 Vint Cerf and others separate the TCP and IP
  functions

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Business Economists Guy Judge, September 2003
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Internet applications and their protocols

• Mainstream Internet applications
• Electronic mail (E-mail) SMTP
• The World Wide Web HTTP
• File Transfer FTP
• Terminal access (remote login) Telnet
• Newsgroups Usenet
• Other Internet applications include
• Chat systems, Videoconferencing, Video and audio
  streaming, Voice over Internet, file-sharing etc.

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Business Economists Guy Judge, September 2003
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The IP address

• Every computer on the Internet has a unique IP
  address - four numbers separated by dots
• e.g. 198.137.240.100
• identifies the main host computer at the White
  House

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Business Economists Guy Judge, September 2003
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Find your IP number

• The State University of New York at Stony Brook
  provides a service whereby you can find out the
  IP number of the Internet computer you are
  connected to.
• Why not try it? (URL on my links page).

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Business Economists Guy Judge, September 2003
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DNS - Domain Name System (1)

• DNS is a hierarchical domain-based naming scheme
  and distributed database system for mapping host
  names and e-mail destinations to IP addresses.
• Domain names are easy (for humans) to remember
  names for the computers on the Internet i.e..
  those that have been assigned IP numbers

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Business Economists Guy Judge, September 2003
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DNS - Domain Name System (2)

• ICANN (Internet Corporation for Assigned Names
  and Numbers) coordinates the assignment of IP
  numbers and Internet domain names.
• InterNIC maintains the register of IP numbers
  and domain names. Companies, other organisations
  and individuals can register a domain name
  through one of the DNS registrars.

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Business Economists Guy Judge, September 2003
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DNS - Domain Name System (3)

• The top level domain covers two identifiers,
  separated by a dot
• generic type - eg .com, .ed (or .co and .ac) -
  recent additions include .biz and .coop
• country codes - eg .uk, .nl, .jp

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Business Economists Guy Judge, September 2003
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DNS - Domain Name System (4)

• Sub-domains can then be created lower down the
  hierarchy by those responsible for that level
• e.g. pbs.port.ac.uk

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Computer networks

• A computer network is a collection of
  autonomous but linked computers.

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Why computer networks?

• Resource sharing
• Communication
• Increased reliability
• Improved scalability
• Cost savings

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Computer networks for communication

• Access to remote information (eg data sources,
  e-commerce, video on demand)
• Person to person communication (eg e-mail,
  videoconferencing)
• synchronous and asynchronous links

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Business Economists Guy Judge, September 2003
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Network topologies

• bus (linear cable)
• ring
• multiple links (irregular topology)

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Business Economists Guy Judge, September 2003
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Network connections

• via
• copper wires
• cable
• fibre optics
• microwaves (radio frequency)
• communication satellites

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Business Economists Guy Judge, September 2003
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Network architecture

• architecture is a set of layers and protocols
• purpose of layer is to carry out services for the
  higher layer in a way that is transparent to the
  higher layer
• layers communicate with their peers according to
  known protocols
• between layers there is an interface

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Business Economists Guy Judge, September 2003
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Design issues for layers

• layers need to
• identify senders and receivers
• have rules for communication (protocols)
• know about different available routes
• have conventions about speed
• identify and correct errors

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Business Economists Guy Judge, September 2003
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Size classification of networks

• Local Area Networks (LAN)
• Wide Area Networks (WAN)
• internets
• Tanenbaum also distinguishes Home Networks,
  Wireless Networks and Metropolitan Area Networks
  (eg based on cable TV)

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Business Economists Guy Judge, September 2003
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LAN

• bounded size
• usually one cable that links all machines -
  linear (bus e.g. Ethernet ) or ring
• high speed
• low delay
• high reliability

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Business Economists Guy Judge, September 2003
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WAN

• spans a whole area or even country
• interconnects a large number of hosts
• irregular topology
• divided into subnets with transmission lines and
  switching elements (routers)
• packet switching technology

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Business Economists Guy Judge, September 2003
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client-server model
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clients

• E-mail client software
• Outlook
• Pegasus
• Eudora
• also web based e-mail systems such as Hotmail and
  Yahoo!

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Business Economists Guy Judge, September 2003
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SMTP

• Simple Mail Transport Protocol
• encodes every e-mail message as a sequence of
  ASCII characters
• Used to send e-mail messages from one server to
  another. Messages can be retrieved with an e-mail
  client using POP or IMAP protocols

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Business Economists Guy Judge, September 2003
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M IM E

• Multipurpose Internet Mail Extension
• specifies how non-text may be transmitted by SMTP

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Business Economists Guy Judge, September 2003
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Key dates in the evolution of the Internet -
Electronic Mail

• 1971 - Ray Tomlinson of Bolt Beranek and Newman
  Inc. (BBN) invents the first e-mail program to
  send messages across a distributed network
• 1972 - Tomlinson adapts the program to run on
  ARPANET where it is immediately taken up with
  enthusiasm
• 1975 - John Vittal develops MSG, the first widely
  available e-mail program

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Business Economists Guy Judge, September 2003
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Key dates in the evolution of the Internet -
precursors of the World Wide Web

• 1965 Ted Nelson sets up project XANADU to
  establish world-wide distributed library of
  information (earlier inspiration from Bush
  1945)
• gopher system developed at University of
  Minnesota
• mid 1980s - hypertext packages such as HyperCard
  (1987) and Guide developed

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Business Economists Guy Judge, September 2003
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Key dates in the evolution of the Internet -
the World Wide Web

• 1989 - creation of the World Wide Web and HTTP at
  CERN(Geneva) by Tim Berners-Lee and others
• 1993 - first publicly available web browser
  (MOSAIC) developed at NCSA
• 1990s - new browsers (Netscape, IE) - with helper
  applications and plug-ins for dealing with
  graphics, video etc.
• 1994 - WC3, the World Wide Web Consortium set up

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Tim Berners-Lee
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remote access or terminal emulation telnet

• telnet allows you to login to other remote
  computers on Internet to which you have access
  rights
• E.g. I can log in to the MIMAS computer at
  Manchester from Portsmouth using MS Telnet

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Business Economists Guy Judge, September 2003
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file transfer

• transferring files from computer to computer on
  the Internet
• FTP File Transfer Protocol
• first established 1971
• FTP and FTP client software (e.g. WS_FTP32)
• anonymous FTP
• more secure protocols such as SSH are now
  preferred

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Business Economists Guy Judge, September 2003
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Internet maps

• There are some nice maps of the Internet
  infrastructure at the websites of
• Telegeography,Inc
• Cybergeography.Org
• For more details see the links2.html file

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Business Economists Guy Judge, September 2003
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Internet organisations and agencies

• No single body in charge, but the following all
  have important roles
• ICANN (Internet Corporation for Assigneed names
  and Numbers)
• ISOC (The Internet Society)
• W3C (World Wide Web Consortium)
• We should perhaps also mention the regulators
• Ofcom (UK) and FCC (US)

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Business Economists Guy Judge, September 2003
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Internet metrics

• The Internet Software Consortium conducts a
  semi-annual survey of the number of Internet
  hosts (see next slide).
• But Zook (2000) cautions us about using this
  measure uncritically

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Business Economists Guy Judge, September 2003
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Internet metrics

• There are also problems in counting the number of
  people online, or the number of web pages (see my
  links page for more details).
• But despite these concerns there is no doubt that
  there has been phenomenal growth in the Internet
  and its use - particularly since around 1994 -
  WHY?

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Reasons for the growth of the Internet and its use

• Network externalities - the value of the Internet
  to any one user is an increasing function of the
  total number of users Rohlfs
• Complementary bandwagon effects - part of the
  value of the Internet derives from the
  availability of complementary products, services
  and applications (e-mail, web browsers, news and
  information services etc..) As the network
  expands there are increased incentives for the
  suppliers of complementary products to reduce
  prices or (improve quality).
• E-Commerce
• Despite the hype and the bursting of the dot.com
  bubble
• the Internet continues to grow and expand into
  new areas

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Business Economists Guy Judge, September 2003
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Metcalfes law or DeLongs law

• Metcalfes Law - the value of the Internet to
  any one user increases as the square of the total
  number of users
• DeLongs Law - the most important and cheapest
  links are established first and it becomes
  increasingly costly to connect the last few users

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Business Economists Guy Judge, September 2003
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Reduction in transactions costs Cost to bank -
typical US funds transfer transaction ()

Source PIU Report on e-commerce
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Business Economists Guy Judge, September 2003
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Internet access flat rate pricing versus other
schemes

• Greenstein suggests flat rate pricing is common
  because
• dial-up access is often over un-metered local
  telephone lines (especially in the US)
• costs of monitoring and billing might exceed the
  revenue benefits
• consumers prefer a flat rate charge so there are
  no unexpected costs
• NB volume independent pricing is used in other
  contexts too - e.g. the Paris Metro (see Odlyzko)

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Business Economists Guy Judge, September 2003
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Other schemes and their reasons

• MacKie-Mason and Varian have proposed a smart
  market mechanism (aka responsive pricing)
• This is because the Internet can become congested
  at times.
• Also some applications make exceptionally heavy
  use of
• bandwidth
• Economists argue that
• price rationing is more efficient than queuing
• users should pay according to their willingness
  to pay - and choose how much to pay and when
• appropriate signals are sent both to consumers
  and producers

The Internet for
Business Economists Guy Judge, September 2003