1. 1 Internet Technologies CSC457

2. 2 Internet Internet is a communication technology. Like telephone it enables people to communicate. Telephones enabled voice communication. Internet enables data communication. Because it spans many countries Internet is called the global network. Other networks were: BITNET, FIDONET, JANET, EARN.

3. 3 Information Infrastructure Internet provides a new infrastructure for communications like postal system, telegraph, and telephone did earlier. New infrastructure makes new industries and application possible, some of which cannot be foreseen.

4. 4 Evolution of the Internet There are many different LAN technologies: Ethernet, Token Ring, ATM, etc. Each has different ways to connect computers, format data packets, data transmission rates, etc and thus incompatible. Desirability of a single network to enable resource sharing.

5. 5 Evolution of the Internet US DoD starts funding research on how to interconnect the networks. 1969 ARPANET was developed this was the first Internet. E-mail was adapted for ARPANET in 1972. 1972 First public demonstration of ARPANET. The telnet protocol, enabling logging on to a remote computer started in 1972. The ftp protocol, enabling file transfers between Internet sites, started in 1973.

6. 6 Evolution of the Internet The first networking protocol used on the ARPANET was the Network Control Program. In 1983, it was replaced with the TCP/IP protocol. In 1993 first graphical browser Mosaic was developed.

7. 7 GROWTH OF THE INTERNET

8. 8 The Underlying Technologies What is inside the Internet? Or What are the key underlying technologies that make it work so successfully? –Packet Switching –Routers/Packet Switches –TCP/IP –Clients + Servers = Distributed Computing –Computer Names.

9. 9 Applications Some applications of the Internet: –World Wide Web (WWW) –Electronic Mail (Email) –Bulletin Boards (Newsgroups) –Audio & Video Services

10. 10 Internet Topology Backbone Network Network Access Provider (NAP) Internet Service Provider (ISP) Users

11. 11 Internet Topology (Detailed) Backbone Network Users RRRR NAPn R NAP1 R NAP2 R NAP3 R ISP R R R RRRRR Users

12. 12 The Way It Works A typical user dials into an ISP using telephone to send a message. The ISP routes the call to the internet through NAP. It may cross the backbone network to reach the final destination.

13. 13 A Typical ISP Subscriber1 Subscriber2 Subscriber3 Subscribern modem1 modem2 modem3 modemn Internet Remote Access Server (RAS) ISP Setup