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Lesson Note

Computer Science

Class - XII

Chapter – Networking Concepts

Topic: Fundamentals, Switching Technique,
Guided and Unguided medium, Types of Network

Short note

A computer network is an interconnected network of autonomous computers. Interconnected means
they are capable of exchanging information and autonomous means no computer in the network can
start, stop or control another.

Need For Networking
Network Goals Applications of Network
1. Resource sharing 1. Sharing – files and peripherals(disk/printer)
2. Reliability 2. Access to remote database
3. Cost factor 3. Communication facilities
4. Communication Medium

Evolution of Networking
Seed is ARPANET(Advanced Research Projects Agency NETwork) planted in 1969 by U.S. Department of
Defense to connect different universities and U.S. defense. Students, scientists, researchers, engineers
started sharing their data and the network expanded rapidly.

INTERNET
Internet is a worldwide network of computer networks. The Internet is made up of many networks each
run by a different company and interconnected at peering points.

How Does Internet Work ?
In Internet, most computers are not connected directly to the Internet. Rather they are connected to
smaller networks, which in turn are connected through gateways to the Internet backbone.
Gateway - A Gateway is a device that connects dissimilar networks.
Backbone - A Backbone is central interconnecting structure that connects one or more networks just like
the trunk of a tree or the spine of a human being.

INTERNET
All computers connected to Internet uses the same set of rules (protocol) for communication and the
protocol is TCP/IP.
• The TCP (i.e., Transmission Control Protocol) part is responsible for dividing the file/message
into packets on the source computer. It (TCP) is also responsible for reassembling the received
packets at the destination or recipient computer.