Chapter 2: The Internet’s Structure and History IB 300: Advanced Computer Sciences. Professor: Nabil Elmjati

Overall Structure of the Internet All real-world networks, including the Internet, are a mix of LANs and WANs  Example: A company or a college One or more LANs connecting its local computers Individual LANs interconnected into a wide-area company network

Structure of a Typical Company Network

Overall Structure of the Internet (continued) Internet Service Provider (ISP)  A wide-area network  Provides a pathway from a specific network to Other networks, or from an individual’s computer to other networks ISPs are hierarchical  Interconnect to each other in multiple layers to provide greater geographical coverage

Structure of a Network Using an ISP

Overall Structure of the Internet (continued) Internet  A huge interconnected “network of networks”  Includes nodes, LANs, WANs, bridges, routers, and multiple levels of ISPs  Early million nodes (hosts)

Communication Protocols A protocol  A mutually agreed upon set of rules, conventions, and agreements for the efficient and orderly exchange of information TCP/IP  The Internet protocol hierarchy  Governs the operation of the Internet  Four layers

Network Services and Benefits Services offered by computer networks  Electronic mail ( )  Bulletin boards  News groups  Chat rooms  Resource sharing Physical resources Logical resources

Network Services and Benefits (continued) Services offered by computer networks  Client-server computing  Information sharing  Information utility  Electronic commerce (e-commerce)

DNS: Domain Name System (System or Server) A Protocol that translates web addresses into IP address.

How can we know the public IP of a web address ? Answer: the nslookup command

A Brief History of the Internet and the World Wide Web: The Internet 

A Brief History of the Internet and the World Wide Web: The Internet 1957 The USSR launches the first satellite, Sputnik. To compete against the USSR's success at launching the first satellite, the United States Department of Defense creates the Advanced Research Projects Agency (ARPA). ARPA is responsible for the development of new technology for use by the military Rand Corporation proposes a new information network so that the United States could successfully communicate after a nuclear war.

 1969 The first host-to-host Advanced Research Projects Agency Network (ARPANET) connection is made on October 25, 1969, between the University of California at Los Angeles, and the Stanford Research Institute, Inc. (SRI) in Menlo Park, California.  1972 ARPANET begins to be used for communicating .  1973 The term “Internet” begins to be used.

 1990 The phrase “World Wide Web” is used for the first time.  1991 Stanford Linear Accelerator (SLAC) becomes the first web server on the Internet.  1992 Internet registration begins for.com,.net..org,.edu, and.gov.  1993 The Internet takes off as part of the world’s fastest growing information network. The World Wide Web is developed in CERN, the Institute for Particle Physics in Switzerland.

The World Wide Web vs Internet  The Internet is a computer network consisting of a worldwide network of computer networks and cables that use the TCP/IP network protocols to facilitate data transmission and exchange.  The World Wide Web is a computer network consisting of a collection of internet sites that offer text, graphics, sound and animation resources through the hypertext transfer protocol.

Hypertext Documents

Summary Computer network: A set of independent computer systems connected by telecommunication links Options for transmitting data on a network: Dial- up telephone lines, DSL, cable modem, Ethernet, Fast Ethernet Types of networks: Local area network (LAN) and wide area network (WAN)

Summary (continued) The Internet is a huge interconnected "network of networks" TCP/IP is the Internet protocol hierarchy, composed of four layers. The World Wide Web is an information system based on the concept of hypertext