The document discusses how the internet works. It describes that the internet was originally created by ARPA and the Department of Defense for military and scientific communications. It is a network of interconnected networks that allows data to still flow even if parts are destroyed. Data is carried through high-speed backbones to smaller networks, allowing any user to exchange data. It discusses the different stages data moves through like finding DNS servers and destination systems. It also describes common hardware components like routers, gateways, switches and hubs. The document outlines public and private IP addresses and protocols like NAT and DHCP. It also briefly discusses mobile internet access through WiFi and mobile data.

1. HOW INTERNET WORKS
A Seminar by
M-SATISH KUMAR

2. INTRODUCTION
 The Internet was created by the Advanced Research
Projects Agency (ARPA) and the U.S. Department of
Defense for scientific and military communications.
 The Internet is a network of interconnected networks.
Even if part of its infrastructure was destroyed, data
could flow through the remaining networks.
 The Internet uses high-speed data lines, called
backbones, to carry data. Smaller networks connect to
the backbone, enabling any user on any network to
exchange data with any other user

3. CONTENT:
 DIFFERENT STAGES INVOLVED.
 DIFFERENT NETWORK COMPONENTS.
 PUBLIC AND PRIVATE IP ADDRESS.
 INFORMATION ABOUT MOBILE IP.

4. DIFFERENT STAGES INVOLVED

6. FIND DNS SERVER

7. FIND DESTINATION SYSTEM

8. DIFFERENT HARDWARE COMPONENTS
ROUTERS:A router is a networking device that forwards
data packets between computer networks
GATEWAYS:A gateway is a node in a computer
network, a key stopping point for data on its way to or
from other networks

9. SWITCH:A network switch is a computer
networking device that connects devices together on
a computer network, by using packet switching to
receive, process and forward data to the destination
device.
HUB: Hub is the most basic networking device that
connects multiple computers or other network devices
together

11. IP ADDRESS
 In order to communicate across the Internet, a
computer must have a unique address.
 Every computer on the Internet has a unique numeric
identifier, called an Internet Protocol (IP) address.
 Each IP address has four parts – each part a number
between 0 and 255. An IP address might look like this:
205.46.117.104.

12. PUBLIC AND PRIVATE IP
 Computers on private LANs do not need a public IP
addresses, since they do not need to be accessed by the
public.
 Therefore, certain addresses that will never be registered
publicly are reserved. These are known as private IP
addresses, and are found in the following ranges:
 From 10.0.0.0 to 10.255.255.255
From 172.16.0.0 to 172.31.255.255
From 192.168.0.0 to 192.168.255.255

13. NAT PROTOCOL

14. DHCP PROTOCOL

15. MOBILE INTERNET
Mainly there are two types of sources:
1) Wifi
2)Mobile Data

18. Major Features of the Internet
• The World Wide Web
• E-Mail
• News
• Telnet
• File Transfer Protocol (FTP)
• Internet Relay Chat (IRC)