Computer : Ch.1 Computer Networks - Notebook work(Notes)

 

Ch : 1 Computer Networks

Computer Network

A computer network is a system of interconnected computers and other devices that help us communicate, share resources and transfer information from one computer to another.

 

Types of network

·         Local Area Network (LAN)

o   LAN is a Local Area Network.

o   LAN covers a small area confined to one building or within close proximity.

·         Metropolitan Area Network (MAN)

o   MAN is a computer network that is larger than LAN.

o   It can cover an entire city or even a large campus connecting computers across buildings far from each other.

o   Examples: Cable television network or telephone company network.

·         Wide Area Network (WAN)

o   It is a network that extends over a large geographical area.

o   It is often created by joining several LANs together.

o   They are linked by optical fiber cables, satellite radio links and microwave radio links.

·         Personal Area Network (PAN)

o   It is a computer network organized around an individual person and is set up for personal use only.

o   It typically involve a computers, phones, printers and tablets.

o   Devices can be wired using USB cables or they can be connected without wires, using Bluetooth.

·         Controller Area Network (CAN)

o   It uses a completely message-based protocol and is specially designed for high-speed in-vehicle communication.

o   It allows communication between microcontrollers and different types of devices in real-time.

o   It is used mainly in automotive and industrial environments.

o   It can also be used in lifts, escalators and automatic doors.

Network Protocol:

A protocol is a set of rules and connections that governs all aspects of communication between computers in a network.

Protocols define the standard methods of information transfer and processing for computers on a network to communicate with each other.

 

Types of Networking Protocol

•          HTTP : It is a standard format to display a HTML page over the web.

•          FTP : It is  used for file transfer over the internet.

•          TCP/IP : TCP and IP are two different protocols that are often linked together.

•          Mail Protocol

•          SMTP : It is used when a mail is sent from an email client to an email server.

•          POP3 : It is used for receiving mails.

•          IMAP : It is used to store email messages on a mail server and download them.

Hub:

When the hub receives a message for a particular computer, it sends it to every other computer on the network. Therefore, hub-based networks are not very safe.

Switch:

A switch functions like a hub but it is smarter. When it receives a message, it checks who it is meant for and sends it to only the specific computer that should receive it. Therefore, networks that use switches are more secure.