The document provides an overview of fundamentals of the Internet and World Wide Web. It discusses the origins and development of the Internet from ARPANET in the 1960s to the modern Internet. It also describes the origins and components of the World Wide Web, including HTTP, URLs, web servers, browsers. The document then explains concepts like IP addresses, domain names, and how they map to human-readable web addresses. It provides brief descriptions of related technologies like FTP and how users can search the Internet.

1. Fundamentals of
Internet and World Wide Web
Lecture 02
By:
Khalid Khan
Department of Computer Science
University of Peshawar
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2.  A Brief Introduction to  Web Servers
◦ Web Server Operation
Internet ◦ General Server Characteristics
◦ Origins ◦ Apache, IIS etc.
◦ What Internet is?  Uniform Resource
◦ IP Addresses Locators
◦ Domain Names ◦ URL Formats
◦ URL paths)
 The World Wide Web  HTTP
◦ Origins ◦ Request Phase
◦ Web or Internet? ◦ Response Phase
 Web Browsers  FTP
 Searching on the
Internet
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3.  1958 – USSR launches Sputnik, first artificial earth satellite.
 1960s – the US Department of Defence (DoD) gave the
concept of a large scale computer network.
 1969-Software called Network Control Protocol (NCP)
provided communication between the hosts.
 The US DoD’s Advanced Research Project Agency (ARPA)
funded the construction of such network – called ARPAnet.
◦ ARPA Net was text based.
◦ Communicate through email.
◦ Technique (packet switching)
◦ Protocol (TCP)
◦ ARPA reach to the development of IP (Internetworking protocol)
creating a network of networks.
◦ Combined set is called TCP/IP
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4.  1970s and early 1980s – other networks such as BITNET and
CSNET were also created but never became dominant
networks.
 1986 – NSFnet, sponsored by National Science
Foundation(NSF) – initially connected five universities, but
after establishment it became available to other institutions
and laboratories too.
 1990 – NSFnet replaced ARPAnet
 1992– NSFnet connected more than 1 million computers
around the world.
 1995 – a small part of NSFnet returned to being a research
network, and the rest became known as INTERNET
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5. A Brief Introduction to Internet
1985 1993
NSFNET founded Web Browser
1969 1983
by The National “Mosaic” invented
ARPANET DOD Mandated
Science by Mark Andreesen
R&D Project Adoption of TCP/IP
Foundation
ARPANET INTERNET
1974 1983
Vinton Cerf ARPANET Split 1991
and Robert Kahn into ARPANET and World Wide Web
Initiated TCP/IP MILNET Released by
Tim-Berners Lee

6.  The Internet is a huge collection of computers
connected in a communications network.
◦ The computers are of every manageable
size, configuration, and manufacturer.
◦ Some of the devices connected are not computers at all
e.g. plotter and printers etc.
 All of these diverse devices to communicate with
each other using a protocol, TCP/IP.
 Each computer on a network is assign a unique ID
called IP address, just like people home or street
address.
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7.  For people, Internet nodes are identified by names, for
computers, they are identified by numeric addresses.
◦ If one wants to send data to the computer on same
network, he needs the physical address of the computer to
which data is intended to be sent.
◦ But if the receiving computer lies on another network, or
Internet for example, then IP address of the recipient is
required to address it.
 The Internet Protocol(IP) address of a machine is a
unique 32-bit number (IPv4), written in the form of
numbers separated by dots(.).e.g. 191.57.126.0.
 New IP standard, approved in 1998, is IPv6 in which the
address space was expanded to 128bits.
◦ This change is essential to face the rapid growth of
computers.
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8.  A domain name represents a group of hosts on the
Internet.
 A full domain name is a sequence of labels separated by
dots
 It combines a host name and a TLD to form a fully
qualified host name which provides a user friendly way to
uniquely identify a site on the Internet.
 The DNS translates fully –qualified names into IP
addresses.
 For example a yahoo website can be reached by typing
http://www.yahoo.com or alternatively you can type the
IP address of the yahoo server (e.g. like 207.168.92.4) in
to browser.
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9.  We would go crazy if we would have to remember the
IP addresses of all the web sites that we wanted to visit
 The Domain Name System translates between domain
names and IP addresses of devices connected to the
Internet
◦ A domain name (a part of the URL) is a unique
alphanumeric name such as upesh.edu
◦ The top level domain name is edu and the
secondary level domain name is upesh in the above
example (there could be up to 127 levels, but more
than 4 is rare)

10.  The fully qualified host name of a computer on
Internet has three major parts:
 The host name: The hostname is the name of the
particular host on the internet.
 The domain name: A domain name is usually the
name of the company that owns the site or a word
or phrase that otherwise describes the site.
 Domain encapsulate host names
 The TLD: It usually refers to the type of
organization that owns the domain name e.g.
com, org, edu, gov, pk etc
. www.university.peshawar.net 10

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12. Domain Name and Host
IP ADDRESSES DOMAIN NAMES
Every device connected
has a unique 32-bit Human
DNS Readable
address
cnn.com
Every device
Translation connected has an
Machine Readable alphanumeric
Between
e.g. 151.196.19.22 address
domain Names
and IP Addresses

13.  Domain Names.
 Generic top level domains
 .com
 .biz
 .info
 .edu
 .mil
 .net, etc.
 Country codes or Country Domain
 .pk, .jp, .cn, .us, etc.

14. 1945 – Vannevar Bush
1945 – Invent Memex
?
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15.  1965 – Ted Nelson
◦ Coined the term “hypertext”
◦ Project: “Xanadu”:
◦ “A File Structure for the Complex, the Changing, and the
Indeterminate.” 20th National Conference, New
York, Association for Computing Machinery, 1965.
 In 1989, Tim Berners-Lee at CETN (European
Laboratory for Particle Physics) proposed a new
protocol for the internet as well as a system of
document access to use it.
 This new system was called World Wide Web
(WWW) which allow scientists around the world
to use the Internet to exchange document to
describe their work.
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16.  The release of the first graphical interface, Mosaic, in
February 1993.
 1995 – 2001
◦ “Dot coms” like AOL, Yahoo, Netscape,
◦ Google
◦ Internet Explorer”
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17.  The Internet and the Web are not the same thing.
 Internet is a collection of computers and other devices
connected by equipment that allows them to communicate
with each other.
 The web is a collection of distributed documents referred to
as “pages” located on computers (servers) all over the world.
 Servers store hypertext markup language(HTML) files and
respond to requests.
 The Internet was quite useful before the Web was developed,
and is still useful without it.
 However, most users use Internet through the use of Web.
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18. The web is based on a three-part architecture.
HTML
HTTP
GUI
Databases
TCP/IP-based network GUI Content
Web clients Web Servers Software
applications

19. The Web operates in a client/server configuration:
 Client: A client computer is one which requests for services to a
server.
 Client uses a software called Web Browser for this purpose.
 Server: A computer that send responds to a client request, using
a software called Web Server.
 HTTP is the most common protocol used for the communication
between browsers and servers.
Examples of browsers are Microsoft Internet Explorer, Netscape
Navigator, Opera, Chrome, Mozilla Firefox etc.
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20.  Web servers are programs that provide documents to the
requesting browsers.
 Servers are slave programs:
◦ A web server stores web pages and delivers those pages upon
client request. A web server software is installed on the web
server.
◦ They act only when requests are made to them by browsers
running on other computers on the Internet.
 Examples of Web Servers are:
 Microsoft Internet Information Server(IIS)
 Apache
 SunONE etc.
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21.  URLs are used to identify documents (resources) on the
Internet.
 Different types of resources identified by different forms of
URLs, but with same general format:
 Scheme: object-address
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22.  Each page of information on the web has a unique address
called the URL at which it can be found.
http://faculty.uscupstate.edu/atzacheva/lecture1.html
The document
can be obtained Host Name - Path to the Web File Name Denotes that the File
using the The Name of Page is Written in HTML
Hypertext Web Server HyperText Markup
Transfer Protocol Language
(HTTP)
2
1 3
Host Name
Protocol File Name

23.  Scheme: object-address
 Scheme: a communications protocol
 Common schemes include
http, ftp, gopher, telnet, file, mailto, and news.
 Most important is HTTP, which supports the Web, and used to
request and send eXtensible Hypertext Markup Language
(XHTML) documents.
 In case of using HTTP, the form of the object address of a
URL is:
 http://fully-qualified-domain-name/path-to-document.html
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24.  All Web communications transactions use the same
protocol, the HTTP.
 The current version of HTTP is 1.1, defined by World Wide
Web Consortium (W3C) in June 2011, as
 HTTP consists of two phases:
 Request phase
 Response phase
 Each HTTP communication (request or response) between a
browser and a Web server consists of two parts:
 Header – contains information about communication
 Body – contains the data of the communication, if there is
any.
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25. i. The Request Phase ii. The Response Phase
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26.  FTP works on the client/server principle.
 A client program enables the user to interact with a server in
order to access information and services on the server
computer.
 Files that can be transferred are stored on computers called
FTP servers.
 To access these files, an FTP client program is used.
 This is an interface that allows the user to locate the file(s) to
be transferred and initiate the transfer process
 There are two modes of transfer in FTP:
 ASCII is used only for files saved in ASCII format (this includes
Postscript files)
 Binary is used for files that are formatted and saved using a
word processing software like WordPerfect
(.txt), spreadsheets (.xls), images (.jpg, .gif), and many
executable programs (.exe) and videos (.avi).
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27.  Searching the Web
 The two most basic and commonly used Web-based search
tools are:
 Directories
 A directory enables you to search for information by selecting
categories of subject matter.
 The directory separates subjects into general
categories, which are broken into increasingly specific
designers.
 http://www.lookmart.com
 Search Engines
 A search engine lets you search for information by typing one
or more words.
 The engine then displays a list of Web pages that contain
information related to your words.
 http://www.google.com.pk/ 27

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