Networking Fundamentals CBSE Class 10 IT 402 Notes for Term 2

What is computer network?

A computer network is an interconnection among two or more computers or computing devices. 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.”

Computer network Definition:-

A computer network has many definition. you can define the computer network as group of networks or a group of two or more similar things or people interconnected with each other is called a network.

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 is done 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: Fullform 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 bluethooth connection between two devices is a good example of PAN. 

LAN (Local Area Network)- The LAN connection is done by wires, Ethernet cables, fibre optics, or Wi-Fi. Comparatively the Local Area Network is Secure than other network because is 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 accross the countries.

Computer networking topologies

The computer network topology means the architectural format of a nework. 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. The internet is the best platform for resources sharing.

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

In additional, You can visit to CBSE website and check the Syllabus for IT(402). Apart from that you can practice IT(402) on given link: IT(402) MCQ