The word "Internet" is derived from "Interconnected Networks."
It is a network of networks where many devices are interconnected and communicate with each other.
History of the Internet
It started in the 1960s, with a project by the Defense Department called "ARPANET".
ARPANET introduced the process of sending data in small packets, making the data more secure and robust.
In the 1980s, the Domain Name System (DNS) and the World Wide Web were developed.
In the 1990s, the commercialization of the Internet began, and services like email, messaging, and online shopping became available.
In the 2000s, social media and mobile internet rose to prominence.
The Internet Today
Today, we use the internet for sending tax documents, video calls, audio calls, data sharing, and many other things.
Internet Service Provider (ISP)
ISPs are those who provide you access to the internet, such as Airtel, Jio, BSNL, etc.
Through ISPs, you connect to the internet.
ISPs are classified on local, regional, and national levels.
Client-Server Model
Interaction between client and server is understood, where the client requests data from the server or updates resources.
The client can make various types of requests, such as GET, POST, PUT, DELETE, etc.
The server processes the request and sends a response.
Protocol Stack
Data is divided into many small packets that are sent over the network.
Each layer has a specific task, such as assigning port numbers, addressing the destination IP address, etc.
Application Layer
Protocols used by specific applications such as SMTP (Simple Mail Transfer Protocol), HTTP (Hypertext Transfer Protocol).
Transport Layer (TCP)
Determines the port number to interact with specified applications.
Network Layer (IP)
Includes the IP address to deliver the data to the destination machine.
Domain Name System (DNS)
Converts the domain name into an IP address, enabling server identification.
Example: Converting www.google.com into its corresponding IP address.
Easy-to-Understand Example
Ramesh used the Flower War website to send flowers, but if the address is unknown, the flowers cannot be sent; similarly, an IP address is necessary to send data over the internet.
Homework for Further Study
Networking devices: Switch, Hub, Router, Modem.
OSI Model and TCP/IP Model
IP Addressing (IPv4 vs IPv6)
In Summary
The functioning of the internet involves a combination of protocols and layers.
These layers help deliver data securely and effectively.
The client-server model focuses on data requests and responses.
ISPs play a crucial role at all levels of the internet.