internet &webTechnology

1. Internet &
WebTechnology
M.SharmilaDevi,M.C.A.,M.Phil.,
Assistant Professor in Commerce with CA
E.M.G.Yadava Women’s College
Madurai-14

2. Definition
• The Internet is the worldwide, publicly accessible
network 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 interconnected
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 documents of the World Wide Web.

3. Basic protocols
• There are three kinds of basic protocols,
* IP protocol
* TCP/IP protocol
* UDP protocol

4. IP: Internet Protocol
• The Internet set of networks are all based on IP,
the Internet Protocol. The Internet Protocol (IP) takes
care of addressing, or making sure that the routers know
what to do with your data when it arrives.
• Data is transmitted in a series of small chunks,
called packets, each approximately 1200 characters in
length.
• The header of each packet includes the destination
address of the system to receive the packet. The
address of that system is the IP address.
• All IP addresses consist of four fields of numbers ieach
one less than 256.
• Any packet containing IP addresses in the form

5. • Internet Protocol (IP) uses addresses which are a series
of four "octet" (byte) numbers in a dotted decimal
notation. For example: 199.246.24.130
• IP addresses are of three classes:
Class A
Class B
Class C
• 132.246.xxx.xxx
• are for systems owned by NRC (actually, it is more
precise to say that they are destined for systems behind
the main NRC National Capital Region router). The
routers in the network use this number to decide where
to forward each packet.

6. • Some addresses, however, are used for internal
networks only. Three sets of addresses were set
aside for that specific purpose:
10.0.0.0 - 10.255.255.255
172.16.0.0 - 172.16.255.255
192.168.0.0 - 192.168.255.255
• Those sets of addresses should never be routed
through the Internet.

7. • TCP: Transmission Control Protocol
The Transmission Control Protocol describes how those
IP packets are to be transmitted. The TCP software
ensures all packets are received and that all packets are
placed in the proper order. It then extracts the data, and
puts it in the proper order.
• UDP: User Datagram Protocol
The User Datagram Protocol is typically used by
applications requiring small amounts of data transfer
(less than one packet at one time). UDP may be viewed
as ``TCP's small brother" since it handles one packet at
a time instead of a string of them.

8. Basic internet terms:
Below are basic internet terms or concepts useful for
understanding what happens when searching for information in
the internet.
• Domain abbreviations (last three characters in URL or address)
edu - Educational institutions
com - Commercial businesses
gov - U.S. government
mil - The U.S. military
org - Other organizations
net - Network/Internet Service Providers
- In a URL address, means an individual is responsible for the
contents

9. • Favorites - A menu option at the top of the screen that shows
any websites that have been previously saved for you to return
to on a different day, much like a traditional bookmark is used
for books.
• Go - A command in Explorer that sits on the top of the screen
with other commands. In Go, Explorer keeps track of most sites
that a user has visited during a session of using Explorer. This
is not saved once you quit Explorer.
• Homepage - Default setting, or the page that opens up when
you start your Browser. A homepage can also be the entry
point for people viewing information that is provided.

10. • Internet - Network of millions of computers used to send
information back and forth to one another. No one person or
group decides what can and cannot be published on the
internet. This means that virtually anyone can publish, and
means that there are large number of sites that contain false
and misleading information. It is important to check who takes
credit for the site you are viewing.
• Links - Hypertext which, when clicked, connects you to another
site or another page within the same site. In most cases, these
links are usually highlighted in blue and are always underlined.
• Online Databases - These are sites that provide access to
mostly newspaper and magazine articles which are not
available through Google or any other search engine. The only
way to see these articles online is to pay a fee. Online
databases are usually specialized and focus on subjects like
social studies or science.

11. • Page - What is on your screen at any given time. The page
includes all the information available to you by scrolling up or
down; however, when you click on hypertext your computer
will 'jump' to a new page.
• Printing - Printing directly off the internet wastes paper
because it is difficult to tell how long a document is. Internet
printing will also include graphics and images you don't need.
The more pictures, fancy fonts, and images, the slower the
printing will be.
To prevent slower printing jobs and save paper, copy the text
you want printed, open a word processing program, paste the
text into a new file, and then print.
• Search Engines - Software that allows you to search the Web
by typing in a topic of interest. Examples of search engines we
use are Google, HotBot, and Northern Light. These search
engines find exact matches from what has been typed in the
search screen to either documents (files) or subjects of files on
the WWW.

12. • URL or Uniform Resource Locator - The address for a specific
file on the web, as well as a method for directing users to a
specific file, at a specific site. To type in a different URL, press
command and L at the same time on a Macintosh computer,
control and L on a PC, or locate the address bar at the top of
the screen, type in the URL, and then press return. The URL for
the Blaine School District Home page is:
http://www.blaine.k12.wa.us.
• Web Browser - To access the WWW, you need a Browser. A
Web Browser is client software that gets information from a
server. It interprets the information, formats it, and displays it
on your computer screen. The most popular browser, and the
one we use most often in Blaine, is Internet Explorer.
• WWW-World Wide Web or Web - Interactive collection of
hypertext pages linked to one another. They may include text,
graphics and/or links to other spots in the Web. The Web is
interactive because a user can click on text or graphics to
navigate (move) to more information or other graphics, sounds
and video that is of interest to them.
•

13. • What is a WAN?
A WAN is a wide area network. It is a group of computers connected
through bridges, routers, hubs and repeaters. Since it is called
a wide area network, the network may extend across buildings on a
campus, across the country, or even around the world.
• What is a LAN?
A LAN is a local area network. A network is a group of computers
connected together by some type of broadband cable, such as
FDDI, Token Ring or Ethernet. Since it is called a local area
network, the network is contained within a single building, or even to
a single floor.
• What is Hypermedia?
• Hypermedia is the ability to display pictures, video, and sound.

14. • What is an Intranet?
An Intranet is a private computer network based on the standards of
the Internet.
Intranets use Internet technologies to link together information
resources of an organization; from text documents to multimedia
documents, from legacy databases to document management
systems. Intranets may also include network security, workgroup
computing, bulletin boards and search engines.
An Intranet may extend across the Internet. This is usually done
using a Virtual Private Network (VPN).
• What is an Extranet?
An Extranet is an intranet which extends beyond the physical
boundaries of a corporation.
Extranets give access to vendors and suppliers, dealers and
distributors to a firm's intranet. Companies include them in order to
facilitate the transfer of information. This is information which not
accessible to the general public. For example: inventory levels,
delivery times, pricing policies, etc.

15. • What is an Address?
An address is name by which a computer can be called or
referenced. An address is also a location of a resource on a
network.
For example: pierobon@pierobon.org
is an address of the mail service.
• What is a Domain?
A domain is logical grouping of computers on a network. It may
include multiple networks. It may also just be a subset of a
network of computers. So domains can have sub
domains.

16. • what is a Domain Name?
Just like people, domains need to have names. A domain name on
the Internet has the following form:
[subdomain].[subdomain].[subdomain].[...].domain
For example my electronic mail address includes my name and my
domain name.
pierobon@pierobon.org
Here org is a domain name.
• What is a Top Level Domain?
The top level domains (TLD) of the Internet are:
com ... for commercial entities
edu ... for four-year educational institutions
gov ... for non-military, United States federal government
instititutions
mil ... for United States military orgianizations
net ... for network operations and Internet Service Providers (ISP)
org ... for non-profit organizations
•

17. • What is a Host?
* A host is a computer that is enabled to function on a
network.
* To be a host on the Internet, a computer must
* Have a domain name; e. g., nasa.gov
* Use the Internet Protocol (IP)
* Be assigned a unique IP address; e. g., 199.246.24.130
* Have a network connection that provides a route to
the Internet
• What is a Port?
* A port identifies an application or a service. It has been set up this
way. There are TCP ports and UDP ports.
* Servers can accept multiple connections on a single port because
of active and passive sockets.
* However, the important thing to remember is that there are two
types of ports: well known and ephemeral.

18. • What is an URL
An Uniform Resource Locator (URL) is the term used to
identify an Internet resource, and can be specified in a
single line of text.
• What is an URN
An Uniform Resource Name (URN) is the term used to
identify an Internet resource, without the use of
a scheme, and can be specified in a single line of text.
• What is an URI
An Uniform Resource Identifier (URI) is used by a
browser to identify a single document, and it too can be
specified in a single line of text.

19. • What is a Socket?
• A socket is an end-to-end connection between a client and a server
identifying:
IP address (client, server)
protocol (TCP, UDP)
port (client, server)
• A socket is a network communications end point. The analogy is to a
wire (the network data connection) being plugged into a socket.
• Sockets come in two primary flavors: active and passive. An active
socket is connected to a remote active socket via an open data
connection. Closing the connection destroys the active sockets at
each end point. A passive socket is not connected, but rather awaits
an incoming connection, which will spawn a new active socket.
• A socket is not a port, though there is a close relationship between
them. A socket is associated with a port, though this is a many-to-
one relationship. Each port can have a single passive socket,
awaiting incoming connections, and multiple active sockets, each
corresponding to an open connection on the port.