Connectivity and the Internet

2. Connectivity – the capability of microcomputer to share
information with other computers
Network – communications system connecting two or
more computers.

3. Personal area network
A personal area network (PAN) is a computer network
used for communication among computer devices
close to one person. Some examples of devices that are
used in a PAN are printers, fax machines, telephones,
PDAs and scanners. The reach of a PAN is typically
about 20-30 feet (approximately 6-9 meters), but this
is expected to increase with technology improvements.

4. Local area network
A local area network (LAN) is a computer network
covering a small physical area, like a home, office, or
small group of buildings, such as a school, or an
airport. Current wired LANs are most likely to be
based on Ethernet technology, although new
standards like ITU-T G.hn also provide a way to create
a wired LAN using existing home wires (coaxial cables,
phone lines and power lines)[2].

5. Campus area network
A campus area network (CAN) is a computer network
made up of an interconnection of local area networks
(LANs) within a limited geographical area. It can be
considered one form of a metropolitan area network,
specific to an academic setting.

6. Metropolitan area network
A metropolitan area network (MAN) is 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. Routers,
switches and hubs are connected to create a
metropolitan area network.

7. Wide area network
A wide area network (WAN) is a computer network
that covers a broad area (i.e. any network whose
communications links cross metropolitan, regional, or
national boundaries ). Less formally, a WAN is a
network that uses routers and public communications
links .

8.  The largest and most well-known example of a WAN is
the Internet. A WAN is a data communications
network that covers a relatively broad geographic area
(i.e. one city to another and one country to another
country) and that often uses transmission facilities
provided by common carriers, such as telephone
companies.

9.  Largest network in the world
 Referred to as the Information Superhighway
 Connects millions of other people and organizations
located throughout the world
 Physical network made up of wires, cables and
satellites
 Web provides a multimedia interface to the numerous
resources available on the Internet

10.  Internet was launched in 1969 when U.S. funded and
developed a national computer network called
Advanced Research Project Agency Network
(ARPANET)
 The internet then was all text – no graphics,
animations, sounds or videos
 Web was introduced in 1992 at the Center for
European Nuclear Research (CERN) in Switzerland.

11.  Web provided a multimedia interface to resources
available on the Internet
 Internet and Web evolved into one of the most
powerful tools of the 21st century
 Being connected in the internet is often described as
being online

12. Some Internet applications
 E-mail
 Web
 Instant messaging
 Remote login
 P2P file sharing
 Multi-user network games
 Streaming stored video
clips
 Internet telephone
 Real-time video
conference

13. Internet
 Internet: loosely hierarchical
“network of networks”
 Major Components: Hosts,
Routers, Communication links
 Protocols: for sending, receiving
of msgs
 e.g., TCP, IP, HTTP, FTP, PPP
local ISP
company
network
regional ISP
router workstation
server
mobile

14. Internet Service
 Communication infrastructure enables distributed
applications:
 Web, email, games, e-commerce, file sharing
 Communication services provided to applications:
 Connectionless unreliable
 connection-oriented reliable

15. Communication Business Transaction
Education
Entertainment
Searching
Security
Shopping

16.  Most popular Internet activity
 Exchange e-mail with your family and friends almost
anywhere in the world.
 Join and listen to discussions and debates on a wide
variety of special-interest topics

17.  Fastest-growing Internet applications
 Window shop, look for the latest fashions, search for
bargains, and make purchases

18.  Search for information became more convenient
 Access some of the world’s largest libraries directly
from your home computer
 Find the latest local, national ,and international news

19.  Find music, movies, magazines and computer games
 Find live concerts, movie previews, book clubs, and
interactive live games.

20.  Take classes on almost any subject
 There are courses just for fun and there are courses for
high school, college, and graduate school credit.
 Open University

21.  Common way to access the Internet is through an
Internet Service Provider (ISP)
 ISPs are already connected to the Internet and provide
a path or connection for individuals and businesses to
access the Internet

22.  Programs that provide access to Web resources
 Connects you to remote computers, opens and
transfers files, displays text and images and provides in
one tool an uncomplicated interface to the Internet
and Web documents
 Allows the user to explore, or to surf, the Web by
easily moving from one website to another.
Examples: Internet Explorer, Mozilla Firefox, Safari,
Opera, Google Chrome

23. (Universal) Uniform Resource Locator (URL) –
location or address of the resources in the internet
Parts of URL
Protocols – rules for exchanging data between
computers
Domain name – name of the server the resource is
located
Top-Level Domain (TLD) – identifies the type of
organization

24. Hypertext Markup Language (HTML) – programming
language used in creating webpages and websites
Hyperlinks – links that connect to other documents
containing related information-text files, graphic
images, audio and video clips.
Applets – widely used to add interest and activity to a
Web site by presenting animation, displaying graphics,
providing interactive games, and much more.

25. TCP/IP - Transmission Control Protocol/Internet
Protocol, the suite of communications protocols used
to connect hosts on the Internet. TCP/IP uses several
protocols, the two main ones being TCP and IP.
TCP/IP is built into the UNIX operating system and is
used by the Internet, making it the de facto standard
for transmitting data over networks. Even network
operating systems that have their own protocols, such
as Netware, also support TCP/IP.

26. Network interface cards
A network card, network adapter or NIC (network
interface card) is a piece of computer hardware
designed to allow computers to communicate over a
computer network. It provides physical access to a
networking medium and often provides a low-level
addressing system through the use of MAC addresses.

27. Repeaters
A repeater is an electronic device that receives a signal
and retransmits it at a higher power level, or to the
other side of an obstruction, so that the signal can
cover longer distances without degradation. In most
twisted pair Ethernet configurations, repeaters are
required for cable which runs longer than 100 meters.

28. Hubs
A hub contains multiple ports. When a packet arrives at
one port, it is copied unmodified to all ports of the
hub for transmission. The destination address in the
frame is not changed to a broadcast address.

29. Routers
Routers are networking devices that forward data
packets between networks using headers and
forwarding tables to determine the best path to
forward the packets. Routers work at the network
layer.