Computer Network

What is a Network ? 

A network is a collection of computers and devices connected together via communication devices and transmission media 

What is a Communication Device ?

A communication device is any type of hardware capable of transferring data, instruction and information between a sending device and receiving devices

DEVICES	DESCRIPTION
Dial-up Modem	Convert digital signals to analog signals
Digital Modems (ISDN, DSL, Cable Modem)	Send and receives data and information to and from a digital line
Wireless Modem	Connect to the internet wirelessly from a computer or mobile device
Network Card	Enable a computer or device that does not have built-in networking capabiltiy to access a network
Wireless Access Point (WAP)	A central communication device that allows computers and devices to transfer data wirelessly among themselves or to transfer data wirelessly to a wired network using wireless technologies such as Wi-Fi
Switch	Similar to a hub but more sophisticated including functionality that allows it control and manage data transmission
Hub	Allows multiple connections to the network

What is Transmission Media ?

Materials or substances capable of carrying one or more signals in a communications channel

Guided Media

• Shielded Twisted Pair
• Unshielded Twisted Pair (UTP)

Widely used transmission media for network cabling and telephone systems

• Coaxial Cable 

consists of a single copper wire surrounded by at least three layers : an insulating material, a woven or braided metal, a plastic outer coating 

• Fiber Optic

uses glass or plastic fiber to carry light (laser) signals 

Unguided Media 

• Cellular Radio (2G, 3G, 4G)

a form of broadcast radio that is used widely for mobile communications, specifically wireless modems and mobile phones 

• Infrared 

Infrared (IR) is a wireless transmission medium that sends signals using infrared light waves 

• Broadcast Radio ( Bluetooth, UWB, Wi-Fi )

a wireless transmission medium that distributes radio signals through the air over long distances and short distance 

• Microwave 

microwave are radio waves that provide a high speed signal transmission

• Communication Satellite 

is a space station that receives microwave signals from an earth-based station, amplifies the signals and broadcast the signals back over a wide area to any number of earth based stations 

ADVANTAGES OF NETWORK

Easy Communication and Speed

 People can communicate efficiently by using a network such as emails, instant messaging, telephony, video conferencing, chat rooms, etc.

Ability to Share Files, Data and Information

It can benefit large organizations to maintain their data in an organized manner and facilitate access for desired people

Sharing Hardware

 By sharing hardware it can reduce the cost of purchasing hardware because there’s no need to have individual  hardware such as printer for each and every computer in the company.

Sharing Software

It can reduce the cost of buying software by networking their computers because networkable versions of software are available.

Security

Sensitive files and programs on a network can be password protected and can only be accessed by the authorized users.

Speed

Sharing and transferring files within networks is very rapid, depending on the type of network.This will save time while maintaining the integrity of files

DISADVANTAGES OF NETWORK

 Breakdowns and Possible Loss of Resources

Breakdown of the whole network due to an issue of the server may lead to loss of important data of the server.

 Expensive to Build

Building a network  for large scale organizations are very pricey especially to buy and replace cables and other hardware .

Security Threats

There are hackers who are trying to steal valuable data of large companies for their own benefit.

 Bandwidth Issues

 Heavy users who consume a lot more bandwidth will affect other users.