Chapter II: Unit- II Technology in E-procurement

The Internet, Intranet, Extranets and the World Wide Web

 Internet
• The Internet is the global system of interconnected 
computer networks that uses the Internet protocol set
 (TCP/IP) to communicate between networks and devices.

• It is a network of networks that consists of private, public,

academic, business, and government networks of local to
global scope, linked by a broad array of electronic, wireless,
and optical (visual) networking technologies.
Cont’d… internet
• The origins of the Internet date back to the development of 
packet switching (the transfer of small pieces of data across various
networks.) and research commissioned by the United States Department of
Defense in the 1960s to enable time-sharing of computers.

• The primary originator network, the ARPANET, initially served as a

backbone for interconnection of regional academic and military networks
in the 1970s.

• The funding of the National Science Foundation Network (a program of

coordinated, evolving projects )as a new backbone in the 1980s,

• The linking of commercial networks and enterprises by the early 1990s

marked the beginning of the transition to the modern Internet, and
generated a sustained exponential growth as generations of institutional, 
personal, and mobile computers were connected to the network.
Cont’d… internet
• Most traditional communication media,
including telephone, radio, television, paper mail
and newspapers are reshaped, redefined, or even
bypassed by the Internet, giving birth to new
services such as email, Internet telephone, 
online music, and digital newspapers.

• Newspaper, book, and other print publishing are

adapting to website technology.
 Intranet 

• An intranet is a computer network for sharing information, easier

communication, operational systems, and other computing services
within an organization, usually to the exclusion of access by
outsiders. 

• The term is used in contrast to public networks, such as the Internet,

but uses most of the same technology based on the Internet protocol set
.

• An intranet is sometimes contrasted to an extranet. While an intranet is

generally restricted to employees of the organization, extranets may
also be accessed by customers, suppliers, or other approved parties. 
 Extranet 

• An extranet is a controlled private network that allows access to partners,

vendors and suppliers or an authorized set of customers – normally to a
subset of the information accessible from an organization's intranet.

• An extranet is similar to a DMZ (demilitarized zone network) (A DMZ

Network is a perimeter network(boarder network) that protects and
adds an extra layer of security to an organization's internal local-area
network from untrusted traffic (untrusted network), in that it provides
access to needed services for authorized parties.

• Historically, the term was occasionally also used in the sense of two
organizations sharing their internal networks over a virtual private network
 (VPN).
 World Wide Web (WWW)

• The World Wide Web (WWW), commonly known as the Web, is

the world's dominant software platform(computer software).

• It is an information space where documents and other 

web resources can be accessed through the Internet using a 
web browser.

• The Web has changed people's lives greatly. It is the primary tool
billions of people worldwide use to interact on the Internet. 

• It was invented by Tim Berners-Lee, in 1989 and opened to the

public in 1991.
Cont’d… www
• Web resources may be any type of downloadable media. 

• Web pages are documents interconnected by hypertext links 

formatted in Hypertext Markup Language (HTML).

• The HTML syntax displays embedded hyperlinks with URLs

(uniform resource locator), which permits users to navigate to
other web resources.

• In addition to text, web pages may contain references to images, 

video, audio, and software components, which are either
displayed or internally executed in the user's web browser to
render pages or streams of multimedia content. 
Cont’d… www
• The terms Internet and World Wide Web are often used without much
distinction. However, the two terms do not mean the same thing.

• The Internet is a global system of computer networks interconnected

through telecommunications and optical networking (is a means of
communication that uses signals encoded in light to transmit information in
various types of telecommunications networks.).

• In contrast, the World Wide Web is a global collection of documents and

other resources, linked by hyperlinks and URLs.

• Web resources are accessed using HTTP (Hypertext Transfer Protocol

 or HTTPS (Hypertext Transfer Protocol Secure), which are application-
level Internet protocols that use the Internet's transport protocols.
 Internet Protocol
What is the Internet Protocol (IP)?
• The Internet Protocol (IP) is a protocol, or set
of rules, for routing and addressing packets of
data so that they can travel across networks
and arrive at the correct destination.
 Cont’d… Internet protocol
• Once the packets arrive at their destination, they are handled
differently depending on which transport protocol is used in
combination with IP. The most common transport protocols are
TCP and UDP.

• TCP/IP Transmission Control Protocol/Internet Protocol:

– A set of computer communication protocols that connect
networks and allows them to communicate with each other.
– TCP verifies data transmission between a client and a server.
 
– TCP/IP is the primary transmission protocol used on the
Internet.
Cont’d… Internet protocol
• UDP/IP: User Datagram Protocol/Internet Protocol
– The User Datagram Protocol, or UDP, is another
widely used transport protocol. It's faster than
TCP, but it is also less reliable.

– UDP does not make sure all packets are delivered

and in order, and it doesn't establish a connection
before beginning or receiving transmissions.
Web page request and delivery protocols

An overview of HTTP: (Hyper Text Transfer

Protocol) 

• The communications protocol used to connect to Web

servers on the Internet or on a local network (intranet).

• HTTP is a protocol for fetching resources such as

HTML(standard mark-up language for documents
designed to be displayed in a web browser.)
documents.
Cont’d… HTTP
• Designed in the early 1990s, HTTP is an
extensible (extendable )protocol which has
evolved over time.

• Due to its extensibility, it is used to not only

fetch hypertext documents, but also images
and videos or to post content to servers, like
with HTML form results.
 Delivery protocols

 Transmission Control Protocol (TCP) is a more

sophisticated, connection-oriented protocol used for
reliable delivery of data that is not required to be
delivered in real time.

 A connection-oriented reliable-delivery protocol called

transmission control protocol (TCP) and

 A connectionless, unreliable-delivery service called user

datagram protocol (UDP).
 Electronic Mail Protocols

• There are three common protocols used to deliver

email over the Internet: the Simple Mail Transfer
Protocol (SMTP) outgoing protocol, the Post
Office Protocol (POP) incoming protocol, and the
Internet Message Access Protocol (IMAP)
incoming protocol.

• All three use TCP, and the first is used to manage the
transmission of email between servers and the last
two are used for accessing electronic mailboxes.
Cont’d… email protocol

The SMTP protocol: Simple Mail Transfer

Protocol
• It is used to forward an email from server to
server.
Cont’d… email protocol
The POP protocol (Post Office Protocol )
• The POP protocol allows the
recovery(retrieval) of emails located on a
remote server.

• It manages the verification of the account

holder via his login credentials.
Cont’d… email protocol
IMAP protocol: Internet Message Access
Protocol
• The IMAP protocol allows you to check emails
from anywhere.

• Therefore, it ensures constant management

between your workstation and the server. Thus,
your emails are better managed, sorted and
classified.
  Markup language
• A markup language is a computer language that uses tags to define
elements within a document.

• Tag: On clothes, tags usually indicate the brand, size of the

clothing, materials used, and the washing instructions.

• In Web pages, tags indicate what should be displayed on the screen

when the page loads.

• Tags are the basic formatting tool used in HTML (hypertext markup
language) and other markup languages, such as XML.

– For example, to create a table on a Web page, the <table> tag is used. The
data that should be inside the table follows the <table> tag, and the table is
closed with a </table> tag.
Cont’d… markup language
• If you want something to show up in bold on a
Web page, you would use the bold tag.

– For example, the HTML:

o This site is the <b>best website</b> ever!

– would show up as:

o This site is the best website ever!)
Cont’d… markup language
• HTML( Hyper text Markup Language) is a markup
language used for creating webpages.

• The contents of each webpage are defined by HTML tags.

– Basic page tags, such as <head>, <body>, and <div> define

sections of the page,
– while tags such as <table>, <form>, <image>, and <a> define
elements within the page.

• Most elements require a beginning and end tag, with the

content placed between the tags.
Cont’d… markup language

• XML(Extensible Markup Language) a met language which

allows users to define their own customized markup
languages, especially in order to display documents on the
internet.
• is used for storing structured data, rather than formatting
information on a page.

• While HTML documents use predefined tags (like the examples

above), XML files use custom tags to define elements.
– For example, an XML file that stores information about
computer models may include the following section:
 End
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