CBSE12th Unit - 2 Chapter 1

 Introduction to Computer Networks

• A computer network is a collection of interconnected devices (computers, printers, servers, etc.) that can communicate and share resources.
• These devices are connected using communication media like cables, wireless signals, etc.
• Networks enable various applications like file sharing, email, video conferencing, and online gaming.

Evolution of Networking

• ARPANET (1969):
• The first-ever wide-area network (WAN).
• Developed by the US Department of Defense.
• Initially designed for military and research purposes.
• Pioneered the concept of packet switching, where data is broken down into smaller units for transmission.
• NSFNET (1985):
• Created by the National Science Foundation (NSF).
• High-speed network designed to support research and education.
• Played a crucial role in the development of the internet.
• INTERNET (1990s):
• The global network of interconnected networks.
• Allows millions of computers worldwide to communicate.
• Evolved from ARPANET and NSFNET.
• Offers a wide range of services like the World Wide Web, email, file transfer, and online communication.

Key Points

• The evolution of networking has been driven by technological advancements and the increasing need for connectivity.
• ARPANET and NSFNET laid the foundation for the internet as we know it today.
• The internet has revolutionized communication, business, education, and many other aspects of society.

In Simple Terms

• Imagine a network of roads connecting different cities.
• ARPANET was like the first few roads built, connecting a small number of places.
• NSFNET was like building a bigger, faster highway system.

The internet is like the entire global road network, connecting every city and town.