intro to internet.

1. Internet and WWW

2.  The Internet is a worldwide, publicly accessible
series of interconnected computer networks that
transmit data by packet switching using the standard
internet protocol (IP).
 It is a "network of networks" that consists of millions
of smaller domestic, academic, business, and
government networks, which together carry various
information and services, such as electronic
mail,online chat,file transfer, and the interlinked web
pages and other resources of the World Wide
Web(WWW).

3. INTERNET ARCHITECTURE

4.  History
 Growth
 today

6. History
 Sputnik
 United States to create the Advanced Research Projects
Agency, known as ARPA, in 1958
 British Post Office, Telenet, DATAPAC and TRANSPAC
collaborated in 1981
 TCP/IP in 1983
 1985 NSF commissioned 56kb/sec n/w backbone using
Fuzzballs followed by commission of 1.5 megabit/second
backbone called NSFnet
 1988 opening the network for commercial interest.The US
Federal Networking Council approved the interconnection of the
NSFNET to the commercial MCI Mail system in that year and the
link was made in the summer of 1989. Other commercial
electronic e-mail services were soon connected, including
OnTyme, Telemail and Compuserve. In that same year, three
commercial Internet Service Providers were created: UUNET,
PSINET,CERFNET

7.  Important, separate networks that offered gateways into, then
later merged with, the Internet include Usenet and Bitnet
 Various other commercial and educational networks, such as
 Telenet,
Tymnet Compuserve and JANET were interconnected with the
growing Internet.
Telenet (later called Sprintnet) was a large privately funded
national computer network with free dial up access in cities
throughout the U.S. that had been in operation since the 1970s.
This network was eventually interconnected with the others in the
1980s as the TCP/IP protocol became increasingly popular
 The ability of TCP/IP to work over virtually any pre-existing
communication networks allowed for a great ease of growth,

8. GROWTH
 World Wide Web project. The Web was invented by English scientist
Tim Berners-Lee in 1989
 An early popular web browser was ViolaWWW, based upon HyperCard.
It was eventually replaced in popularity by the Mosaic web browser.
 In 1993, theNational Center for Supercomputing Applications at the
University of Illinois released version 1.0 of Mosaic, and by late 1994
there was growing public interest in the previously academic, technical
Internet.
 By 1996 usage of the word Internet had become commonplace, and
consequently, so had its misuse as a reference to the World Wide Web
 Meanwhile, over the course of the decade, the Internet successfully
accommodated the majority of previously existing public computer
networks (although some networks, such as FidoNet, have remained
separate). During the 1990s, it was estimated that the Internet grew by
100% per year, with a brief period of explosive growth in 1996 and 1997

9. Todays Internet
 Aside from the complex physical connections that make up its
infrastructure,
 the Internet is facilitated by bi- or multi-lateral commercial
contracts (e.g., peering agreements), and by technical
specifications or protocols that describe how to exchange data
over the network. Indeed, the Internet is essentially defined by its
interconnections and routing policies.
 Review, philosopher N.J. Slabbert, a writer on policy issues for
the Washington,D.C. –based Urban Land Institute, has asserted
that the Internet is fast becoming a basic feature of global
civilization, so that what has traditionally been called “civil
society” is now becoming identical with information technology
society as defined by Internet use.

10. Summary of
Stages in development of internet
 Innovation (1961-1974)
 The concept of packet switiching
 The first “killer app”of internet is born
 Invention of client server computing
 TCP/IP is invented
 Instituitionalization (1975- 1995)
 TCP/IP adopted as DoD standard
 Personal computers invented
 Domain Name server introduced (DNS )
 www is born
 NSFNET created
 Commercialization(1995 onwards)
 Fully commercial internet is born.
 Netwoks as AT&T,Sprint,UUNet,MCI take over operations of backbone
 Ecommerce begins with pur online retail stores and auctions

11. WWW
 The World Wide Web (commonly shortened to the Web) is a
system of interlinked hyertext documents accessed via the
internet. With a Web browser, a user views Web pages that may
contain text, images,videos, and other multimedia and navigates
between them using hyperlinks.
 The World Wide Web was created in 1989 by Sir Tim Berners-
Lee, working at CERNin Geneva, Switzerland. Since then,
Berners-Lee has played an active role in guiding the
development of Web standards (such as the markup languages
in which Web pages are composed), and in recent years has
advocated his vision of a Semantic web. Robert Cailliau, also at
CERN, was an early evangelist for the project.

12. Working of WWW
 Typing of URL in web browser or using hyperlink
 Resolving of IP address Using DNS
 HTTP request sent to the web server,html page
requested first ,parsed and then additional req is
sent for images and other files.
 browser then renders the page onto the screen as
specified by its HTML, CSS and other Web
languages. Any images and other resources are
incorporated to produce the on-screen Web page
that the user sees.

13. Internet protocol suite

14. Internet Protocol Suite

15.  Different internet access methods
ACCESS METHOD MAXIMUM DATA
RATE
Telephone modem 56kbps
Ethernet (local area n/w) 10/100mbps
ISDN 112-128 KBPS
Cable modem 30 Mbps (theoretical)
1.5 Mbps(practical)
Asymmetric digital subscriber line 1.5-9Mbps(network to users)
(ASDL) 16-640kbps(users to network)
Wireless local area network 1-2 Mbps

16. Internet service provider ISP
 An Internet service provider (abbr. ISP, also called
Internet access provider or IAP) is a business or
organization that provides consumers or businesses
access to the internet and related services. I
 In the past, most ISPs were run by the phone
companies.
 Now, ISPs can be started by just about any individual
or group with sufficient money and expertise.
 In addition to Internet access via various technologies
such as dial-up and DSL, they may provide a
combination of services including Internet, domain
name registration and hosting, web hosting etc

18. Internet Governing Bodies
 IAB-Internet Architecture Board
 ICANN –Internet Corporation for assigned
name and numbers
 IEGS-Internet Engineering Steering group
 IETF-Internet Engineering task force
 W3C-World Wide Web consortium

19. Governing Bodies in India
 IAMAI- Internet and mobile Association of
India
 ISPAI- Internet service provider Association
of India
 IOAI –Internet and online Association of India

20. NETWORK TOPOLOGY
In computer networking, topology refers to the
layout of connected devices

21.  bus
 ring
 star
 tree
 mesh

22. Bus

23.  Bus networks use a common backbone to connect all devices. A
single cable, the backbone functions as a shared communication
medium that devices attach or tap into with an interface connector.
A device wanting to communicate with another device on the
network sends a broadcast message onto the wire that all other
devices see, but only the intended recipient actually accepts and
processes the message. Ethernet bus topologies are relatively easy
to install and don't require much cabling compared to the
alternatives. 10Base-2 ("ThinNet") and 10Base-5 ("ThickNet") both
were popular Ethernet cabling options many years ago for bus
topologies. However, bus networks work best with a limited number
of devices. If more than a few dozen computers are added to a
network bus, performance problems will likely result. In addition, if
the backbone cable fails, the entire network effectively becomes
unusable.

24. Ring

25. Ring
 In a ring network, every device has exactly two neighbors for
]
communication purposes. All messages travel through a ring in the
same direction (either "clockwise" or "counterclockwise"). A failure in
any cable or device breaks the loop and can take down the entire
network.
 To implement a ring network, one typically uses FDDI, SONET, or
Token Ring technology. Ring topologies are found in some office
buildings or school campuses.

26. Star
 Many home networks use the star topology. A star network features
a central connection point called a "hub node" that may be a
network hub, switch or router. Devices typically connect to the hub
with Unshielded Twisted Pair (UTP) Ethernet. Compared to the bus
topology, a star network generally requires more cable, but a failure
in any star network cable will only take down one computer's
network access and not the entire LAN. (If the hub fails, however,
the entire network also fails.)

28. Tree
 Tree topologies integrate multiple star topologies
together onto a bus. In its simplest form, only hub
devices connect directly to the tree bus, and each hub
functions as the root of a tree of devices. This bus/star
hybrid approach supports future expandability of the
network much better than a bus (limited in the number of
devices due to the broadcast traffic it generates) or a
star (limited by the number of hub connection points)
alone.

30. Mesh
 Mesh topologies involve the concept of routes. Unlike each of the
previous topologies, messages sent on a mesh network can take
any of several possible paths from source to destination. Some
WANs, most notably the Internet, employ mesh routing.
 A mesh network in which every device connects to every other is
called a full mesh. As shown in the illustration below, partial mesh
networks also exist in which some devices connect only indirectly to
others.

31. Mesh