The World Wide Web and the Internet MIS XLM.B Jack G. Zheng May 13 th 2008

2 Overview The Internet World Wide Web Searching on the Web

3 Introduction The Internet a world-wide network of networks and computers based on IP (Internet Protocol) World Wide Web, or Web An Internet application based on HTTP protocol

The Internet Image source:

5 Internet: Putting It Together Adapted from figure B.8 on page 114 Internet backbone

6 How are computers connected world wide? The Internet Backbone Major sets of connections Who operates the Internet backbone? Network service provider (NSP): Also called backbone operator, usually providing services to ISPs MCI, AT&T, … (see more here)see more here ISP (internet service provider) is a company that provides individuals, organizations, and businesses access to the Internet Biggest ISP 1 AOL: 22.2M users; MSN: 8.7M (2003); Comcast: 7.0M; EarthLink: 5.4M; SBC: 5.1M GSU? GSU wireless access 1 Data from: (Q4 2004)

7 Internet Servers and Applications Internet server computer provides information and services on the Internet Web server Mail server FTP (file transfer protocol) server Router Connects different networks (routing) Client computer

8 Internet Communication Protocols Communication protocol is a set of rules and format to transfer information TCP/IP (transmission control protocol/Internet protocol) The featured protocol of the Internet Application protocols HTTP (hypertext transfer protocol) FTP (file transfer protocol)

World Wide Web Total Sites Across All Domains September June 2005 Source:

10 Understanding WWW Some history Tim Berners-Lee, the creator of the Web (1989) Read more Three most important things for Web HTML (hypertext markup language) HTTP (hypertext transfer protocol) URL or URI (uniform resource locator)

11 Domain Name [Domain Name System (DNS)] A system that provides the mapping between IP and domain name Internet Corporation For Assigned Names and Numbers (ICANN) Top-level domains: 2 letter country code: us, uk, jp, ca, au, cn, … Created in 1980.com – commercial or for-profit business.net – Internet administrative organization.org – professional or non-profit organization.edu – educational institution.gov – U.S. government agency.int – international treaties organization.mil – U.S. military organization Created in 2000 coop, info, biz, museum, name, pro, aero

12 Understanding URL The complete link is a URL http is the protocol www2.gsu.edu is the domain www2.gsu.edu/~wwwaux/ is the web site (of GSU Auxiliary and Support Services) index.htm is the actual file (web page).

13 Web Server Web server Web server hosts websites, providing files and applications (services) Market Share for Top Servers Across All Domains. Source: netcraft.com Web applications software applications delivered through web technologies (HTTP, HTML, web server, browser,...) Examples Searching Shopping News Forum Survey BLog …

14 Web Client (Browser) Web browser software (web client) Provides a web interface for users It understands HTML, scripts and works with other plug-ins Web browser products: WorldWideWeb Internet Explorer (Microsoft) Mozilla (formerly Netscape Navigator) Firefox

15 Searching on the Web Two major ways to seek information on the web Searching: using a true search engine Navigating: using structures, such as directories, site maps, indexes Search engine: an application that indexes and organizes resources on the web for people to search Directory search engine Yahoo! Directory Google Directory (open directory Automated search engine Automated search engine uses software agent (web crawler) technologies to search the Web and put resources into databases; then users search by key words or other criteriakey words

16 Web Resources Histories About search engine How does DNS work Internet access information