Chapter 2: The Internet’sStructure 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-areacompany 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 toOther networks, or from an individual’s computerto other networks

ISPs are hierarchical

Interconnect to each other in multiple layers toprovide 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 2003

170 million nodes (hosts)

Communication Protocols

A protocol

A mutually agreed upon set of rules, conventions,and agreements for the efficient and orderlyexchange 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 (email)

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.

DNS:

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

DNS(Cont):

A Brief History of the Internet and theWorld Wide Web: The Internet

http://www.youtube.com/watch?v=rRpcSjck4wo

A Brief History of the Internet and theWorld 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.

1964• 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 email.

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 independentcomputer systems connected bytelecommunication 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 "networkof networks"

TCP/IP is the Internet protocol hierarchy,composed of four layers.

The World Wide Web is an information systembased on the concept of hypertext