1. The Internet An interconnected network of thousands of networks and millions of computers linking biz’s, educational institutions, govt. agencies & individuals together.

2. W W W The Internet’s most popular services, providing access to over one billion 1. web pages, 2. documents, 3. files, 4. audio and 5. video services. These pages are linked using mainly HTTP

3. History of the Internet 1946 - First electronic circuit was created. 1950’s - First network created (between a keyboard and a computer). 1960 - RAND (Research & and Nuclear Development Corporation) a World War II think tank felt that all data in computers should be connected. Link various defence units & contractors. Even if part of the network is destroyed, the remaining should continue to operate. Every machine is equal in status. 1963 - First geosynchronous satellite launched by the USA. 1969 - ARPANET (Advanced Research Project Agency Network). It is a connection of network between University of California at LA (UCLA), University of Utah, University of California at Santa Barbara (UCSB), Stanford Research Institute (SRI). These four were the first 4 nodes.

4. History continued… 1970 - Electromagnetic waves were used for data transmission in the form of packet radio or tactical radio communication. 1972 - Ray Tomlinson developed electronic mail. Created a mail media (or adressing system). 1973 - 23 nodes exist. 75% traffic is e-mail. 1974 - Internetting protocol made by Bob Kahn & Vint Cerf. Multiple packet switching was refined until finally known as TCP/IP. Robert Metcalfe’s Harvard PhD thesis outlines the Ethernet. Goes on to join XEROX Palo Alto Research Center. 1982 - TCP/IP (Transmission Control Protocol/ Internet Protocol) becomes the protocol suite for ARPANET. This leads to one of the first references to an "Internet" of connected networks.. European Unix Network (EUNET) begins.

5. Final days! 1983 to 84 - Standard for Internet is developed and TCP/IP used absolutely. Berkeley releases Unix 4.2, incorporating TCP/IP. The Internet has 500 Hosts. 1989 - Tim-Berners Lee of CERN (Centre Européenne pour la Recherche Nucléaire) created the HTTP protocol. 1992 - The WWW ( World Wide Web) is released by CERN. Number of host on the Internet is 1 million. 1993 - First graphical web browser known as MOSAIC is made for the Internet at NCSC (National Center for Super Computing at University of Illinois). 1994 - Number of Internet host are more than 3 million. 1995 - Network providers assumes major role of Internet. More than 4 million host. 1996 onwards - I guess you know what is happening now...

6. Some Internet Concepts and Terms Circuit Switching Used in telephone industry. Only one connection at a time and a continous connection, so not a a very effective system. Message Switching Transmission is a major factor. Travel of data between nodes require next destination to authorise transmission. Data is taken to the next node and stored temporarily until delivered to the next destination. There is a time queue and time is wasted! Useful for simple transmissions like telex.

7. Circuit Switching Diagram source Source to destination Destination node

8. Message Switching links Nodes A B C D AB BC CD

9. Packet Switching Data is sent in packets and each packet may arrive at different times. Decision to make of splitting and sending is decided by sender’s node. Each packet has a header providing information at final destination of the data arrangement. Used commonly for all Internet transmission larger than a certain specified size.

10. Packet Switching Diagram Packet 1 Packet 3 Packet 2 Packets Delay Packet 1 Packet 2 Packet 3 Packet 1 Packet 2 Packet 3 Time Queueing Delay

11. Information SuperHighway Logical application of the Internet denotes suites of advances made in the field of communication technology. Data access, transfer rate, storage and retrieval. Application in electronic mail, publishing, information retrieval & info. sharing