How internet works

working of internet

1. HOW INTERNET WORKS ? BY ANURAG KUMAR 12D173

2. Internet The Internet is a worldwide collection of computer networks, cooperating with each other to exchange data using a common software standard. The Internet was created by the Advanced Research Projects Agency (ARPA) and the U.S. Department of Defense for scientific and military communications.

3. Internet Internet allows users to: connect easily through ordinary personal computers and local phone numbers; exchange electronic mail (E-mail) with friends and colleagues with accounts on the Internet; post information for others to access, and update it frequently; access multimedia information that includes sound, photographic images and even video; and access diverse perspectives from around the world.

4. How the Internet Works TCP/IP Routing Traffic Across the Internet Network Layers on Client & Server end

5. How the Internet Works - TCP/IP Every computer and network on the Internet uses the same protocols (rules and procedures) to control timing and data format The protocol used by the Internet is the Transmission Control Protocol/Internet Protocol, or TCP/IP . No matter what type of computer system you connect to the Internet, if it uses TCP/IP, it can exchange data with any other type of computer.

6. How the Internet Works - Routing Traffic Across the Internet Most computers don't connect directly to the Internet. Instead, they connect to a smaller network that is connected to the Internet backbone . The Internet includes thousands of host computers (servers), which provide data and services as requested by client systems . When you use the Internet, your PC (a client) requests data from a host system. The request and data are broken into packets and travel across multiple networks before being reassembled at their destination.

7. How the Internet Works - Network Layers on Client & Server end Internet Also known as a “host”…

8. Clients and Servers Client program Running on end host Requests service E.g., Web browser GET /index.html

9. Clients and Servers Client program Running on end host Requests service E.g., Web browser Server program Running on end host Provides service E.g., Web server GET /index.html “Site under construction”

10. Client-Server Communication Client “sometimes on” Initiates a request to the server when interested E.g., Web browser on your laptop or cell phone Doesn’t communicate directly with other clients Needs to know the server’s address Server is “always on” Services requests from many client hosts E.g., Web server for the www.cnn.com Web site Doesn’t initiate contact with the clients Needs a fixed, well-known address

11. Data traveling process Five layers Lower three layers implemented everywhere Top two layers implemented only at hosts Transport Network Datalink Physical Transport Network Datalink Physical Network Datalink Physical Application Application Host A Host B Router

12. Logical Communication Layers interacts with peer’s corresponding layer Transport Network Datalink Physical Transport Network Datalink Physical Network Datalink Physical Application Application Host A Host B Router

13. Physical Communication Communication goes down to physical network Then from network peer to peer Then up to relevant layer Transport Network Datalink Physical Transport Network Datalink Physical Network Datalink Physical Application Application Host A Host B Router