Revision Notes for Class 12 History Chapter 10 Computer
Networks
We live in a highly connected world where computers, devices, and people are part of
large communication networks. A computer network is formed when two or more
computers or digital devices are linked together, allowing them to share information
and resources.
Common examples include not just computers, but also printers, mobile phones, and
storage devices, all communicating through wired or wireless means.
Networks make it possible for users to send emails, browse websites, place audio or
video calls, and even access a shared printer from different computers.
Devices that are part of a network and can send, create, or receive data are called
nodes. These nodes can be computers, smartphones, switches, routers, or other
hardware like printers.
Each network is made up of networking devices such as switches, routers, and modems.
These devices help in connecting and managing different computers at homes, schools,
offices, and across continents. For secure and efficient communication, data sent over a
network is broken into packets, allowing for fast transfer and reliable delivery.
Evolution of Computer Networks
The roots of computer networking started in the 1960s with the ARPANET research project
in the US. ARPANET aimed to connect different academic and research centers so that
scientists could effectively collaborate. Over the years, this small, specialized network
evolved into the modern Internet.
● 1969: First successful communication between UCLA and SRI via ARPANET.
● 1971: Email introduced; @ symbol used for addresses.
www.vedantu.com 1
, ● 1983: TCP/IP protocol adopted, forming the base of the Internet.
● 1990: The invention of HTML and URLs led to the birth of the World Wide Web.
● 1997: Introduction of Wi-Fi standards, enabling wireless connectivity.
Types of Networks
Computer networks can be classified according to area coverage and data speed. The
main types are:
● PAN (Personal Area Network): Covers a small area (10 metres), like connecting a
phone to a laptop using Bluetooth.
● LAN (Local Area Network): Connects computers within a room, building, or
campus. Offers high speed and secure data transfer.
● MAN (Metropolitan Area Network): Spans a city using cable or wireless.
Commonly seen in cable television or broadband networks.
● WAN (Wide Area Network): Connects large geographical regions or the world.
The Internet is the biggest WAN.
Networking Devices and Their Functions
To set up and maintain networks, several devices are required. Each plays a distinct role
in ensuring smooth communication:
● Modem (MOdulator DEModulator): Converts digital data from computers to
analog signals for transmission over telephone lines or vice versa.
● Network Interface Card (NIC): Allows a device to connect to a wired Ethernet
network and is identified by a unique MAC address.
● RJ45: A connector with eight pins used to plug Ethernet cables into devices.
www.vedantu.com 2
Networks
We live in a highly connected world where computers, devices, and people are part of
large communication networks. A computer network is formed when two or more
computers or digital devices are linked together, allowing them to share information
and resources.
Common examples include not just computers, but also printers, mobile phones, and
storage devices, all communicating through wired or wireless means.
Networks make it possible for users to send emails, browse websites, place audio or
video calls, and even access a shared printer from different computers.
Devices that are part of a network and can send, create, or receive data are called
nodes. These nodes can be computers, smartphones, switches, routers, or other
hardware like printers.
Each network is made up of networking devices such as switches, routers, and modems.
These devices help in connecting and managing different computers at homes, schools,
offices, and across continents. For secure and efficient communication, data sent over a
network is broken into packets, allowing for fast transfer and reliable delivery.
Evolution of Computer Networks
The roots of computer networking started in the 1960s with the ARPANET research project
in the US. ARPANET aimed to connect different academic and research centers so that
scientists could effectively collaborate. Over the years, this small, specialized network
evolved into the modern Internet.
● 1969: First successful communication between UCLA and SRI via ARPANET.
● 1971: Email introduced; @ symbol used for addresses.
www.vedantu.com 1
, ● 1983: TCP/IP protocol adopted, forming the base of the Internet.
● 1990: The invention of HTML and URLs led to the birth of the World Wide Web.
● 1997: Introduction of Wi-Fi standards, enabling wireless connectivity.
Types of Networks
Computer networks can be classified according to area coverage and data speed. The
main types are:
● PAN (Personal Area Network): Covers a small area (10 metres), like connecting a
phone to a laptop using Bluetooth.
● LAN (Local Area Network): Connects computers within a room, building, or
campus. Offers high speed and secure data transfer.
● MAN (Metropolitan Area Network): Spans a city using cable or wireless.
Commonly seen in cable television or broadband networks.
● WAN (Wide Area Network): Connects large geographical regions or the world.
The Internet is the biggest WAN.
Networking Devices and Their Functions
To set up and maintain networks, several devices are required. Each plays a distinct role
in ensuring smooth communication:
● Modem (MOdulator DEModulator): Converts digital data from computers to
analog signals for transmission over telephone lines or vice versa.
● Network Interface Card (NIC): Allows a device to connect to a wired Ethernet
network and is identified by a unique MAC address.
● RJ45: A connector with eight pins used to plug Ethernet cables into devices.
www.vedantu.com 2
