3. What is Internet?
15-Jul-17 3
The internet or Internet is the global system of interconnected computer
networks that use the Internet protocol suite (TCP/IP) to link devices
worldwide.
A computer network is any set of computers or devices connected to each other
with the ability to exchange data.
Internet were planted in 1968 when US Department of defense sponsored a
project name ARPANET (Advance Research Projects Network).
Internet is a global network of networks which either uses the TCP/IP protocol
or are able to interact with TCP/IP networks via gateways and provides users
with electronic mail messaging, remote login, file transfer, network news the
www etc.
The internet offers access to data, graphics, sound, software, text and people
through a variety of services and tools for communication and data exchange.
6. Types of Computer Networks
15-Jul-17 6
Local Area Network (LAN): A small network constrained to a small geographic area like a home,
office, or group of buildings e.g. a school.
Wide Area Network (WAN ): A larger network that covers a large geographic area. WANs are used
to connect LANs and other types of networks together, so that users and computers in one
location can communicate with users and computers in other locations.
Metropolitan Area Network (MAN): A network that connects two or more Local Area Networks or
Campus Area Networks together but does not extend beyond the boundaries of the immediate
town, city, or metropolitan area. Multiple routers, switches & hubs are connected to create a
MAN.
Wireless Local Area Network (WLAN): A type of local area network (LAN).
Personal area network (PAN): A computer network organized around an individual person
within a single building.
Storage area network (SAN)
Virtual private network (VPN )
7. Intranet vs. Extranet
15-Jul-17 7
Intranets and Extranets may or may not have connections to the Internet. If
connected to the Internet, the intranet or extranet is normally protected from being
accessed from the Internet without proper authorization.
Intranet: A local or restricted communications network, especially a private
network created using World Wide Web. It may consist of many interlinked local
area networks and also use leased lines in the wide area network. Typically, an
intranet includes connections through one or more gateway computers to the
outside Internet.
Gateway: A gateway is a network node (router) that connects two networks using
different protocols together.
Extranet: An extranet is a network or internetwork that is limited in scope to a
single organization or entity but which also has limited connections to the
networks of one or more other usually, but not necessarily, trusted organizations or
entities.
8. World Wide Web
15-Jul-17 8
The World Wide Web is by far the most exciting and diverse part of the
Internet.
The World Wide Web (commonly shortened to the Web ) is a system of
interlinked hypertext documents accessed via the Internet.
World Wide Web was created in 1989 by Sir Tim Berners-Lee, working at
CERN in Geneva, Switzerland.
WWW is a set of programs standards and protocols that allow the multimedia
and hypertext files to create, display and linked on the internet.
From the late 1960 to early 1990 the internet was a communications and
research tool used almost exclusively for academic and military purpose This
changed radically with the introduction of the World Wide WEB.
9. HTML
15-Jul-17 9
HTML (Hypertext Markup Language) is the language used by the web pages in the
World Wide Web.
"Hypertext" refers to links that connect webpages to one another, either within a
single website or between websites.
HTML markup includes special "elements" such as <head>, <title>, <body>,
<header>, <footer>, <article>, <section>, <p>, <div>, <span>, <img>, and many
others.
10. Key Components of The Internet
15-Jul-17 10
TCP: Transmission control protocol (TCP) was first introduced in 1974. TCP messages were
messages that were encapsulated, and then de-capsulated, kind of like how a letter is placed in
an envelope. It focused on the reliability of networks to make sure that the messages and
information being transferred would arrive safely.
Modem: Connects your computer to an Internet service provider.
IP Address: Used to identify computers.
Packets: Information being transmitted through the Internet is broken up into small packets.
Routers: Routers are the devices that transfer packets from one computer to another. They
ensure that the packets reach their destination quickly and efficiently.
Domain Names: Domain names refer to specific computers or organizations on the Internet.
They specify the location of websites such .au->(Australia), .ca->(Canada) etc.
WWW
HTML
E-mail
12. Communication Services
15-Jul-17 12
E-mail: Used to send electronic message over the internet.
Telnet: Used to log on to a remote computer that is attached to internet.
Newsgroup: Offers a forum for people to discuss topics of common interests.
Internet Relay Chat (IRC): Allows the people from all over the world to
communicate in real time.
Mailing Lists: Used to organize group of internet users to share common
information through e-mail.
Internet Telephony (VoIP): Allows the internet users to talk across internet to
any PC equipped to receive the call.
Instant Messaging: Offers real time chat between individuals and group of
people. Example: Yahoo messenger, MSN messenger, Hangout etc.
13. Information Retrieval Services
15-Jul-17 13
File Transfer Protocol (FTP): Enable the users to
transfer files.
Archie: It’s updated database of public FTP sites
and their content. It helps to search a file by its
name.
Gopher: Used to search, retrieve, and display
documents on remote sites.
14. Web Services
15-Jul-17 14
Web services allow exchange of information between applications on the web.
Using web services, applications can easily interact with each other.
15. File Transfer Protocol (FTP)
15-Jul-17 15
File Transfer Protocol (FTP) is a standard Internet protocol for transmitting
files between computers on the Internet over TCP/IP connections.
FTP was originally defined in 1971, prior to the definition of TCP and IP, and
has been redefined many times.
A good example of how FTP is used today is by web developers, who will
connect to their web server using FTP and send updated versions of their web
pages to the server.
Although many FTP servers require logins, many FTP servers also allow
anonymous FTP login, which only require a username and e-mail with no
password.
FTP is insecure. Username and password are sent to the server they're both
sent as plaintext and could be intercepted and read.
17. E-Mail
15-Jul-17 17
Email (electronic mail) lets you type and send a message to anyone,
anywhere in the world who has an Internet connection and an email account.
Just like a regular letter, except it’s electronic.
There are two parts to an e-mail message: Header, Body.
Header: The header of an e-mail message contains the name and the e-mail
address of the recipient of the message, as well as the message’s subject. If
you are sending the message to more than one person, the header will
contain the names and addresses of all the people you are sending it to.
Body : The body of an e-mail message is the message itself.
A typical e-mail address might look like : abc@gmail.com
CC (Carbon Copy): To send a copy to a second person but don't want to
address them directly, click here and write their Email address, they will
receive their carbon copy at the same time as the recipient.
19. E-Commerce
15-Jul-17 19
E-commerce (electronic commerce or EC) is the buying and selling of goods and services, or the
transmitting of funds or data, over an electronic network, primarily the internet.
The beginnings of e-commerce can be traced to the 1960s, when businesses started using
Electronic Data Interchange (EDI) to share business documents with other companies.
E-commerce is conducted using a variety of applications, such as email, online catalogs and
shopping carts, File Transfer Protocol, and web services.
More companies now try to entice consumers directly online, using tools such as digital coupons,
social media marketing and targeted advertisements.
The benefits of e-commerce include its around-the-clock availability, the speed of access, the
wide availability of goods and services for the consumer, easy accessibility, and international
reach.
Examples: eBay, amazon, flipkart etc.
21. Electronic Meeting Systems
15-Jul-17 21
Group meeting software platform that provides electronic
features that facilitates participation, problem-solving and
decision-making.
The unique features of EMS systems overcome the
limitations of traditional face-to-face meetings such as lack
of participation, criticism and domination of the
proceedings by a few members.
Types:
Audio Conferencing
Video Conferencing
Computer Conferencing
24. Internet Connection Type
15-Jul-17 24
Dial-up: Dial-up access is a form of Internet access via telephone line. The client uses a modem
connected to a computer and a telephone line, to dial an Internet service provider's (ISP) node
to establish a modem-to-modem link, which is then routed to the Internet.
DSL ( Digital subscriber line): DSL, which stands for Digital Subscriber Line, uses existing 2-
wire copper telephone line connected to one’s home so service is delivered at the same time as
landline telephone service. Customers can still place calls while surfing the Internet.
Broadband wireless access: Wireless Broadband is a technology that provides high-speed
wireless internet and data network access over a wide area.
Satellite: In certain areas where broadband connection is not yet offered, a satellite Internet
option may be available. Similar to wireless access, satellite connection utilizes a modem.
ISDN: Integrated Services Digital Network allows users to send data, voice and video content
over digital telephone lines or standard telephone wires. The installation of an ISDN adapter is
required at both ends of the transmission—on the part of the user as well as the Internet access
provider.
Cable modem: A cable modem is a type of modem that provides access to a data signal sent
over the cable television infrastructure.
25. Firewall
15-Jul-17 25
A system designed to prevent unauthorized access to or from a
private network.
Firewalls can be implemented in both hardware and software,
or a combination of both. Firewalls are frequently used to
prevent unauthorized Internet users from accessing private
networks connected to the Internet, especially intranets.
The term firewall originally referred to a wall intended to
confine a fire or potential fire within a building.
Firewall technology emerged in the late 1980s when the
Internet was a fairly new technology in terms of its global use
and connectivity