Introducing The Best Networking Notes For CBSE Class 12 (Computer Science)

Know a to z about computer Networking

Overview

Firstly, Networking notes for CBSE class 12 contains 10 marks and this is completely theory portion for class 12 board exam. The sample papers of CBSE is given link. Apart from that you visit the link to practice the Computer Science MCQ.

What is Network?

A computer network is an interconnection among two or more computers or computing devices. A group of two or more similar things or people interconnected with each other is called a network. A computer network is made with different types of hosts (also called nodes) like server, desktop, laptop,
cellular phones or other types of devices.

“Data in a network
is divided into smaller chunks called packets.”

Devices related to a computer network are:

1. Hub: is a network device used to connect different devices through wires. It is like a switch.

2. Switch: A switch is a networking device that is used to connect multiple computers in a network. When the data packet arrives in a network, the switch extracts the destination address from the packet and sends the packet to the destination. To build a LAN( Local Area Network) we need a switch.

3. Router: A router is a device that connects a local area network to the internet. A router helps to receive the data, analyze it and transmit it to other networks. A router can be wired or wireless. A wireless router can provide Wi-Fi access to smartphones and other devices. 

4. Bridge: It is a network device that connects between two networks by Bridge.

5. Repeater: A repeater is an analog device that works with signals on the cables to which it is connected. The weakened
signal appearing on the cable is regenerated and put
back on the cable by a repeater.

6. Modem: Modem stands for ‘MOdulator DEModulator’. This device used for conversion between analog signals and
digital signals.

7. Gateway: A gateway is a  network node that can be implemented completely in software, hardware, or a combination of both.

8. Registered Jack-45 or RJ45: It is an eight-pin connector that is used exclusively with Ethernet cables for networking. 

9. Ethernet Card: Another name of Ethernet Card is Network Interface Card(NIC). It  is a network adapter used to set up a wired network. Each NIC has a MAC address, which helps in uniquely identifying the computer on the network. 

MAC address: Full form is Media Access Control.  The physical or hardware address is a unique value associated with a network adapter called a NIC. Each MAC address is a 12-digit hexadecimal numbers (48 bits in length), of which the first six digits (24 bits) contain the manufacturer’s ID called Organisational Unique Identifier (OUI) and the later six digits (24 bits) represents the serial number assigned to the card bythe manufacturer.
Example

Types of networks

Networks are categorized into the followings format on the geographical area covered and data transfer rate.

PAN ( Personal Area Network)- This type of network formed by connecting a few personal devices like computers, laptops, mobile phones, smart phones, printers etc. Personal Area Network (PAN) may be wireless or wired. The bluetooth connection between two devices is a good example of PAN. 

LAN (Local Area Network)- The LAN connection is done by wires, Ethernet cables, fiber optics, or Wi-Fi. Comparatively the Local Area Network is Secure than other networks because it has a minimum area. 

MAN (Metropolitan Area Network)- The extended form of LAN which covers a larger area like a city is known as Metropolitan Area Network (MAN). Metropolitan Area Network (MAN) can cover o 30-40 km in area / city. Compare to LAN , the MAN is costly to maitainance because of large area.

WAN (Wide Area Network)-Wide Area Network connects computers and other LANs and MANs, which are spread across different geographical locations of a country or in different countries or continents. Wide Area Network(WAN) spread across the countries.

Networking Topologies

The proper arrangement of computers and other peripherals/devices in a network is known as Topology.

The Common network topologies are
1. Mesh topology :

Each communicating device is connected with every other device in the network.

Advantages:
a. It can handle large amounts of traffic since multiple nodes can transmit data simultaneously.

b. This topology is also
more secure as compared to other topologies because
each cable between two nodes carries different data.

Disadvantages: 

a. Wiring is complex and cabling cost is high in
creating such networks

b. Compare to other networks, It is costly.

2. Ring topology : All the nodes are connected and form a ring.

Advantages: a. The nodes connected with each
other thus forms a ring.

b. The ring topology is unidirectional.

Disadvantages: 

a. The data can be transmitted in one direction only.

b. If one node shuts down, it affects whole network.
3. Bus topology : all the nodes in network are connected through a strait cable in Bus topology.

Advnatages: a. Data can be received by any of the nodes connected to the bus.

b. This is  cheaper than other networks. 

Disadvantages: 

a. Bus topologies are considered as less secure and less reliable.

b. The network dependency is belongs to central cable.
4. Star topology : This topology is known as very effective, efficient and fast as each device is directly connected with the central device. 

Advnatages:

a. It is a very reliable because one cable or nodes disconnected but it does not impact the other nodes on the network. 

b. This is  less expensive compare to other networks. 

Disadvantages: 

a. Central node dependency is the one of main drawback of this network.

b. Compare to Bus topology , It is expensive.
and
5. Tree topology : This topology lso known as Hybrid Topology. This is a hierarchical topology. In this topology data transmitted from source first reaches the centralised device and from there the data passes through every branch where each branch can have links for more nodes.

Advnatages:

a.  This is easy to expand.

b. It is a join multiple topolgy.

Disadvantages: 

a. The installation process is difficult.

b. It is a expensive topology.

Internet, Web, and Website

Internet: It is a widespread network across the boundaries of countries. It is also known as the network of networks. Internet is the best platform for resource  sharing.

WWW [World Wide Web]: In short, the web is the ocean of information, and all the information is shared using websites.

Website: It is a collection of web pages or web documents. Web pages are designed using HTML ( HyperText Markup Language) and other scripting languages like PHP, ASP , JSP. A  unique address or path for each resource located on the web.

URL: A unique address or path for each resource located on the web. Examples: http://www.airindia.in ,http://www.cbse.in, http://www.iqcliq.com

Difference between a website and webpage: A single web document designed with HTML or other scripting language published on the internet is called webpage.

Collection of webpages are called websites.

Static and Dynamic website: A Static Website is displayed in a web browser exactly as it is stored. It contains web pages with fixed content coded in HTML and stored on a web server. A static website does not require web programming or database design. 

A Dynamic Website requires web programming and database design. A dynamic website contains information and content that changes, depending on server updates. When the information is updated or changed within the database, it changes on the site.

Web server: A web server stores the website’s files, namely all HTML documents and their related assets, including images, CSS stylesheets, JavaScript files, fonts, and video.

What is hosting a website?

It is the procedure for housing, serving, and maintaining files for one or more Web sites. 

Difference between add ons and plugins.

Plug-in is a complete program and add-on is not a program.For example Flash is a plug-in made by adobe and is required to play a video in flash player. 

On the other hand, an add-on is not a complete program. It is used to add a particular functionality to a browser.

What are cookies?

Cookies are simple text files generated during accessing websites on a browser. These files are located in temp folder of your system.

VoIP:-Voice over Internet Protocol (VoIP), is a technology that allows you to make voice calls using a broadband Internet.