This document provides an overview of computer networks. It defines a network as two or more connected computers that share information. All networks require devices, hubs or switches to connect multiple devices, and routers to handle communication as more devices connect. Each device needs an IP address for identification and location. The document discusses key aspects of networks including size (LANs and WANs), protocols, topology, hardware components, and cabling infrastructure. It provides examples of how different types of networks are structured. The purpose of networks is to facilitate communication, sharing of hardware, files and software between connected devices.

1. Deborah Dotson
September 12, 2010

2. Is this what you think of when you
hear the word “network”?

3. Or maybe this
type of
“Network”?

5. Glossary
Networks
Infrastructure
Switches
Devices Protocol
Hardware
Topology Routers
Internet
OSI

6. A simple explanation is that a Network is two computers connected to
share information, but of course we know it is often much more.
All networks start from this basic concept. Any device connected to the
network is called a “network device”. When several devices are
connected, they need a “hub”. When many devices are connected they
need routers and switches to handle the communication.
Each device is given an “address” usually called an “IP” address. This
is a numerical label. The IP Address serves two functions -host or
network interface identification and location addressing
Here are four computers connected:
http://en.wikipedia.org/wiki/IP_address

7. When considering a Network, you probably
think about the Internet….
Definitions of internet on the Web:
•A computer network consisting of a worldwide network of computer networks
that use the TCP/IP network protocols to facilitate data transmission and
exchange
wordnetweb.princeton.edu/perl/webwn
•The Internet is a global system of interconnected computer networks that use
the standard Internet Protocol Suite (TCP/IP) to serve billions of users
worldwide. ...
en.wikipedia.org/wiki/Internet
•Any set of computer networks that communicate using the Internet Protocol. (An
intranet.); The Internet, the largest global internet
en.wiktionary.org/wiki/internet
•Often confused with the World Wide Web, the term Internet actually refers to
the combined collection of academic, commercial, and government networks
connected over international telecommunication backbones and routed using IP
addressing.
nsit.uchicago.edu/docs/glossary/

8. A more in depth explanation of
determining the scope of a
Network involves the following:
 Size
 Protocol
 Topography
 Hardware
 Cabling/Infrastucture

9.  Size - there are several types of networks, but
the most common are LANS and WANS.
A Local Area Network (LAN) covers a small physical area, like a home, office, or small
groups of buildings, such as a school.
Some of the characteristics of LANS are their higher data-transfer rates, smaller
geographic area, and they don’t need to lease telecommunication lines.
A Wide Area Network (WAN) is used to connect a LAN and other types of networks
together. The purpose of this so that the computers in one place can communicate with
computers in other locations.
For example in your school district they probably have a private WAN, but may have
another to provide a connection to the Internet.

10. What is Protocol?
Rules about appearance, speaking, listening and understanding
are considered the protocols of conversation. They represent
different layers of communication and together they help
people communicate successfully.
Protocols also apply to computers. Network
engineers have written rules for communication
that must be strictly followed for successful
host-to-host communication.
http://en.wikipedia.org/wiki/Protocol_(computing )

11. Protocols are often called the Open System Interconnection
or “OSI Model” and they help define the implementation
of a networking framework

12. Topography is the “backbone” of a network
and the “map” of how the communication
between devices will flow
Types of Topography

13.  Hardware - Computer networks
normally consists of three parts:
 Clients: The user workstations and
peripherals (such as printers)
 Infrastructure/Cables -The wires,
fiber optics, or transmission media
that the data moves through
 Networking electronics: Devices that
move, route, and store data for users

14. These devices act like an Air Traffic Control Tower and the Controllers themselves
– they get the data and transmit the data and make sure that everything gets to it’s
destination in a timely and safe manner.
Switch
Routers
Hub

15. Cables – these are used transmit
data in the network

16. Examples of Networks and
the “topography” of their
Communication between
devices – this may be how
your network works…..

17. Computer networks can be used for several purposes:
 Facilitating communications. Using a network, people can communicate
efficiently and easily via email, instant messaging, chat rooms, telephone,
video telephone calls, and video conferencing.
 Sharing hardware. In a networked environment, each computer on a
network may access and use hardware resources on the network, such
as printing a document on a shared network printer.
 Sharing files, data, and information. In a network environment,
authorized user may access data and information stored on other
computers on the network. The capability of providing access to data and
information on shared storage devices is an important feature of many
networks.
 Sharing software. Users connected to a network may run application
programs on remote computers.
http://en.wikipedia.org/wiki/Computer_network

19. References
http://searchnetworking.techtarget.com/generic/0,295582,sid7_gci1166812,00.html
http://www.cisco.com/en/US/prod/collateral/switches/ps9441/ps9402/ps9512/brochure_panduit_DC_i
nfrastructur_topologies.pdf
http://www.netc.org/network_guide/
http://www.lpdatafiles.com/supplements/Networks.pdf
http://en.wikipedia.org/wiki/IP_address
http://www.engineer.ucla.edu/stories/2004/Internet35.htm
www.webopedia.com. http://www.webopedia.com/TERM/s/switch.html
http://networkbits.net/lan-components/local-area-network-lan-basic-components/
http://madeit.co.cc/computer-network-part-23/
http://madeit.co.cc/computer-network-part-23/
http://fcit.usf.edu/network/
http://www.lpdatafiles.com/supplements/Networks.pdf
http://www.netc.org/network_guide/
http://www.tech-soup.com/learn...ge4774.cfm
http://www.tech-soup.com/learn...ge4772.cfm
http://www.tech-soup.com/learn...ge4773.cfm
http://whatis.techtarget.com/

20. Picture References
Page 2 - network1.jpg
www.trickledown.wordpress.com
Page 6
Pictures of Computers
http://jfcablinginc.com/ESW/Images/ComputerNetwork.jpg?xcache=9519
Page 8
http://madeit.co.cc/computer-network-part-23/
Page 13
Switch Box http://www.garyolsonassoc.com/hp_procurve_2650.jpg
Cisco Routers - http://www.afsat.net/Products/Page%207%20=%20CiscoRouters.png
Netgear Hub http://www.ssos.com/hubs.jpg
Page 14
pictures of blue cables http://www.intellisec.co.za/images/network%20cabling%202.jpg -
Ethernet cables - http://www.jotechcommunications.com/wp-
content/uploads/2008/12/cabling.jpg
Little Guy - http://www.icsnet.co.uk/images/network.jpg
Page 15
Basic Network pic http://www.netafull.com.ar/netservicios/images/router.jpg
Large Network http://support.novell.com/techcenter/articles/img/nc200205fFig1.gif