A Brief History of the Internet

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A Brief History of the Internet
2
Internet The early years

• The Proliferation of LANs
• Engineers have devised many LAN technologies
• LAN performance determines cost high performance
  LANs are more expensive
• A particular LAN technology may only work with
  specific computers

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Internet The early years

• The Proliferation of LANs

Star topology
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Internet The early years

• The Proliferation of LANs

Ring topology
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Internet The early years

• The Proliferation of LANs

Bus topology
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Internet The early years

• The Proliferation of LANs

Ethernet sharing
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Internet The early years

• The Proliferation of LANs
• A LAN technology is chosen for its speed, ease of
  use, and the availability of interfaces for
  specific computers. Most large organization use
  many LAN technologies

8
Internet The early years

• LANs are incompatible
• Various LAN technologies are completely
  incompatible.

Accounting Dept.
Shipping Dept.
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Internet The early years

• LANs are incompatible
• Various LAN technologies are completely
  incompatible.

Simply connecting the cables cannot make them
work together
Accounting Dept.
Shipping Dept.
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Internet The early years

• Wide Area Technologies Exist

A wide area network technology (WAN) differs from
a set of disjoint transmission lines because the
WAN includes an additional special purpose
computer at each side that connects to the
transmission lines and keeps communication
independent of the computers that use the WAN
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Internet The early years

• Wide Area Technologies Exist

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Internet The early years

• Few WANs, Many LANs
• WANs and LANs are Incompatible
• Many LAN and WAN technologies exist, and most are
  incompatible with each other. One cannot produce
  a usable, large network merely by interconnecting
  the wires from two different networks.

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Internet The early years

• The Desirability of A Single Network

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Internet The early years

• The Internet Emerges
• ARPANET
• Advanced Research Project Agency (ARPA) funded
  research projects to research new approaches to
  connecting LANs and WANs.
• A prototype system that researchers built became
  known as an internetwork Internet.

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Internet The early years

• The Internet Emerges

Diagrams of two nodes on the ARPANET IMP -
Interface Message Processors
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Internet The early years

• The Internet Emerges

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Internet The early years

• The Internet Emerges

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Internet The early years

• Internet Software
• Computer software forms an important part of the
  technology that makes it possible to interconnect
  networks

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Internet The early years

• The Name is TCP/IP
• Two pieces of Internet software stand out as
  particularly important and innovative
• Internet Protocol software provide basic
  communication
• Transmission Control Protocol Provide reliable
  communication

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Internet The early years

• An Open System
• The Internet project aspired to produce an open
  system that permitted computers from all vendors
  to communicate.

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Internet The early years

• Summary
• The Internet began as a research project funded
  by ARPA. Researchers studied ways to connect
  computers that used various kinds of networks.
  The name Internet refers to both the project and
  the prototype network system that researchers
  built.
• TCP/IP is the software necessary to make the
  Internet works. The software hides the detail of
  the underlying hardware and provides the illusion
  of a seamless system.
• The Internet is an open system.

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Internet Incredible Growth

• 1981 The Internet connects about 100 computers
  at research sites and universities
• 20 years later 60,000,000
• Year computers Year computers
• 1983 562 1991 500,000
• 1984 1,024 1992 727,000
• 1985 1,961 1993 1,200,000
• 1986 2,308 1994 2,217,000
• 1987 5,089 1995 4,852,000
• 1988 28,174 1996 9,472,000
• 1989 80,000
• 1990 290,000

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Internet Incredible Growth
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Internet Incredible Growth
By 1999 a computer was added to the Internet
every second.
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Internet Incredible Growth
By 2006 more than 10 computers were added to the
Internet every second.
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Internet Incredible Growth

• Factors contribute to its growth
• Advances in computer science research the
  introduction of UNIX operating system
• UNIX meets TCP/IP enables connection of LANs to
  the Internet
• US Military Chose the Internet The military
  funded and adopted the Internet, technologies
  were developed at civilian sites

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Internet Incredible Growth

• Factors contribute to its growth
• National Science Foundation (NSF) Takes a Leading
  Role connect universities to the Internet
• NSF decided that to keep the US competitive, it
  needed to extend network access to every science
  and engineering researcher.
• The NSFNET

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Internet Incredible Growth

• Factors contribute to its growth
• The NSFNET Backbone

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Internet Incredible Growth

• Factors contribute to its growth
• The ANS Backbone IBM, MERIT, and MCI formed a
  nonprofit company, Advanced Networks and Services
  (ANS)
• ANS owned the transmission lines and computers
  that comprised the network ARPANET and NSFNET
  were funded by government
• First step toward commercialization and
  privatization of the Internet

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The Global Internet

• Internet starts from the USA expanded to the
  globe
• Electronic mail connection use existing voice
  telephone network require a modem and a piece
  of communication software

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The Global Internet

• Internet starts from the USA expanded to the
  globe
• In the UK JANET

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The Global Internet

• Internet starts from the USA expanded to the
  globe
• In Europe Ebone

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The Global Internet

• Internet starts from the USA expanded to the
  globe
• In Hong Kong HARNET

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The Global Internet
1998, every populated country in the world is
connected
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Internet A Global Information Infrastructure

• Infrastructure basic foundations on which
  society depends on electricity power stations
  and supply facilities, railways, roads
• New infrastructure makes new industries possible

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Internet A Global Information Infrastructure

• Communication Infrastructure
• Postal mail services adopted the nation of
  universal access and delivery and individual and
  send a letter to any other individual.
• The telegraph changed the basic communication
  infrastructure because it introduced high speed
  delivery
• Telephone changed the communication
  infrastructure by extending communication
  services to individual homes and offices, and by
  providing the instantaneous communication needed
  for interactive conversation

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Internet A Global Information Infrastructure

• The Internet Infrastructure
• The basic Internet communication facilities are
  both general and efficient, almost any network
  applications can use the Internet
• The Internet offers a wide variety of services.
  Most of the services currently available had not
  been invented when the Internet was first
  designed.
• The Internet is a global infrastructure. Although
  it offers many services, the Internets chief
  advantage lies in the design of TCP/IP software
  that has accommodated changes in computers,
  networks, and services

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Summary

• Many different LAN technologies that are
  completely incompatible.
• WANs exist
• Few WANs, Many LANs
• WAN and LAN are incompatible
• Desirable to have a single seamless network

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Summary

• ARPANET
• ICP/IP
• Open Systems
• Computer science research, UNIX, NSFNET, TCP/IP
  contributed to the rapid growth of the Internet.
• Internet is a global information infrastructure.

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Sharing transmission path
Communication Path
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Sharing transmission path
Sharing saves cost
Communication Path
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Sharing transmission path
Sharing introduces delay
Communication Path
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Sharing transmission path
Sharing introduces delay
Communication Path
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Sharing using Selectable Channels
Carrier 1
Communication Path
Carrier 2
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Sharing using Selectable Channels
Each channel is assigned a unique carrier which
encodes the information of that communication
channel
Carrier 1
Communication Path
Carrier 2
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Sharing by Taking Turns
C
A
Divide data to be transmitted into small trunks,
call a packet and transmit one packet at a time
D
B
Data to be transmitted
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Sharing by Taking Turns
C
1st packet from B to D
A
AC
BD
AC
BC
D
B
1st packet from A to C
2nd packet from A to C
1st packet from B to C
48
Sharing by Taking Turns
Packet Switching
C
1st packet from B to D
A
AC
BD
AC
BC
D
B
1st packet from A to C
2nd packet from A to C
1st packet from B to C
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Packet Switching Avoids Delay
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Packet Switching Avoids Delay
A customer ordered a single item
Another ordered 50 items
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Each packet must be labeled
C
1st packet from B to D
A
AC
BD
AC
BC
D
B
1st packet from A to C
2nd packet from A to C
1st packet from B to C
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Computers Have Addresses
C
A
10.0.0.1
AC
BD
AC
BC
D
Each computer attached to the network is assigned
a unique number called address
B
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Computers Have Addresses
C
A
10.0.0.1
AC
BD
AC
BC
D
Each packet contains the address of the computer
that send it and the address of the computer to
which it is sent
B
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Packets are Not All the Same Size
C
A
10.0.0.1
AC
BD
BC
D
B
Packets can have different sizes
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Packets Transmission Seems Instantaneous
C
A
AC
BD
BC
D
A packet switching system permits multiple
computers to communicate across a shared network
with minimal delay because it divides each
conversation into small packets and arranges for
the computer that sharing a network takes turns
sending packets
B
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Sharing is Automatic
C
A
AC
BD
BC
D
B
From a computers point of view, obtaining fair
access to a shared network is automatic the
network hardware handles the details.
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Many Devices Can Use Packet Switching
C
A
AC
BD
BC
D
B
Many type of devices can connect directly to a
computer network, each such device must contain a
small computer that handles communication
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Relevance to the Internet
All data is transferred across the Internet in
packets
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Relevance to the Internet
A sender divides a message or document into
packets and transfer the packets across the
Internet
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Relevance to the Internet
A receiver re-assembles the original message from
the packets that arrive.
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Relevance to the Internet
Packets from many machines traverse the Internet
at the same time.
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Summary

• Packet switching a fundamental technique used
  to ensure faire access to shared network
  resources.
• Before data can be transferred across a network,
  it must be divided into small trunks packets
• Each computer connected to a network has a unique
  address
• Each packet contains a header records the
  sending and receiving computers addresses
• Each computer takes turns to send its packet. One
  each turn, a computer sends one packet.

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Internet A Network of Networks

• How multiple packet switching networks can be
  interconnected to form an Internet that function
  like a single, large network.

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Use A Computer to Interconnect Networks
Interconnecting Computer
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Use A Computer to Interconnect Networks
Computers that interconnect networks are
dedicated to the interconnection task. They can
use conventional hardware and run on
special-purpose software that starts
automatically when the system is powered on and
remains operating all the time.
Interconnecting Computer
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Interconnection Computers Pass Packets
Interconnecting Computer
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Interconnection Computers Pass Packets
Interconnecting Computer
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Interconnection Computers Pass Packets
Interconnecting Computer
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Interconnection Computers Pass Packets
Interconnecting Computer
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Interconnection Computers Pass Packets
Interconnecting Computer
An interconnecting computer is call router
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Routers are Building Blocks of the Internet

• The Internet is not a single computer network
• It consists of thousands of computer networks
  interconnected by dedicated, special purpose
  computers called routers

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Routers are Building Blocks of the Internet

• The Internet is not a single computer network
• It consists of thousands of computer networks
  interconnected by dedicated, special purpose
  computers called routers

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The Hierarchical Structure of the Internet
Major ISP
Major ISP
Regional ISP
Regional ISP
Regional ISP
Local ISP
Local ISP
Local ISP
subscribers
subscribers
subscribers
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Where Packets Travel
Major ISP
Major ISP
Regional ISP
Regional ISP
Regional ISP
Local ISP
Local ISP
Local ISP
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Where Packets Travel
Major ISP
Major ISP
Regional ISP
Regional ISP
Regional ISP
Local ISP
Local ISP
Local ISP
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Where Packets Travel
Major ISP
Major ISP
Regional ISP
Regional ISP
Regional ISP
Local ISP
Local ISP
Local ISP
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Where Packets Travel
Major ISP
Major ISP
Regional ISP
Regional ISP
Regional ISP
Local ISP
Local ISP
Local ISP
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Where Packets Travel
Major ISP
Major ISP
Regional ISP
Regional ISP
Regional ISP
Local ISP
Local ISP
Local ISP
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Where Packets Travel
Major ISP
Major ISP
Regional ISP
Regional ISP
Regional ISP
Local ISP
Local ISP
Local ISP
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Where Packets Travel
Major ISP
Major ISP
Regional ISP
Regional ISP
Regional ISP
Local ISP
Local ISP
Local ISP
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Interconnecting Networks was Revolutionary
Interconnecting Computer (Router)
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Summary

• To the user the Internet seems to be a single
  network
• It in fact consists of thousands of networks
  interconnected by a dedicated device known as
  routers.
• A router can connect LAN/LAN, LAN/WAN, WAN/WAN
• Networks in the Internet are arranged into a
  conceptual hierarchy of ISPs.
• Using routers to interconnect networks produced a
  revolution.

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ISPs Broadband and Wireless Access

• How your compute can connect to and use the
  Internet

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ISPs Broadband and Wireless Access

• How your compute can connect to and use the
  Internet

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Internet Service Providers and Fees

• A company that provides Internet access is known
  as an Internet Service Provider (IPS)
• ISP levy two types of fees
• A charge for using the Internet
• A charge for a physical connection to the
  Internet

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Leased Line

• Dedicated connection, available all the time
  (24/7)
• Expensive
• Large business users

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Dial-Up Access
ISPs Computer Attached To the Internet
Users Computer
Voice Telephone system
Modem
Modem
ISPs Permanent Connection to The Internet
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Modern Technologies Offer Inexpensive Dedicated
Access

• Cable Modem From cable TV
• DSL (ADSL) Digital subscriber line
  (Asynchronous digital subscriber line)
• Wireless Access

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Modern Technologies Offer Inexpensive Dedicated
Access

• DSL (ADSL) for residential users
• A separate pair of copper wires connects each
  residence to the telephone office
• The technology sends digital data over the same
  wires that are used for conversational telephone
  service, there is no interference. Telephone
  calls do not interfere with Internet use, and
  Internet use does not interfere with telephone
  calls.

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Wi-Fi and 3G

• Most laptop has Wi-Fi
• 3G Mobile phone access to the Internet