WWW AND INTERNET PROTOCOL

World Wide Web

History of WWW

• In its early years, the Internet was used primarily by the government, scientists, and educational institutions.

• Despite its popularity in academia and with government researchers, the Internet went virtually unnoticed by the general public and the business community for over two decades because it required a computer, and it was hard to use.

• However, technology improved and new applications quickly followed. – First, communications hardware improved, and then

computers gained speed and better graphics capabilities.

Tim Proposed Idea of WWW

• Then, in 1989, a researcher named Tim Berners-Lee proposed the idea of the World Wide Web while working at CERN (a physics laboratory in Europe).

• He envisioned the World Wide Web as a way to organize information in the form of pages linked together through selectable text or images (today’s hyperlinks) on the screen. It became a popular way for researchers to provide written information to others.

First Graphically Based Web Browser

• In 1993, a group of professors and students at the University of Illinois; National Center for Supercomputing Applications (NCSA) released Mosaic, the first graphically based Web browser.

• Mosaic used a graphical user interface and allowed Web pages to include graphical images in addition to text.

• Soon after, use of the World Wide Web began to increase dramatically because the graphical interface and graphical Web pages made using the World Wide Web both easier and more fun than in the past.

Mosaic 3.0 running on Windows XP, displaying the web site

Today’s Web Pages

Today’s Web pages are a true multimedia experience. They can contain text, graphics, animation, sound, video, and three-dimensional virtual reality objects.

Today, most companies regard their use of the Internet and World Wide Web as an indispensable competitive business tool, and many individuals view the Internet as a vital research and communications medium.

The World Wide Web

It is a system of interlinked hypertext documents accessed via the Internet. With a web browser, one can view web pages that may contain text, images, videos, and other multimedia and navigate between them by using hyperlinks. [Wiki]

Internet & WWW

The Internet and the World Wide Web are not synonymous.

The Internet is a collection of interconnected computer networks, linked by copper wires, fiber-optic cables, wireless connections, etc.

In contrast, the Web is a collection of interconnected documents and other resources, linked by hyperlinks and URLs.

The World Wide Web is merely a service accessible via the Internet, along with many other services including e-mail, file sharing, and others described below.

Web pageHTMLHyperlinkWeb siteHome pageWeb serverWeb browser

WWW Terminologies

Web Page

Web Page: a hypertext document (HTML File) on the World Wide Web that can include text, pictures, sound, and video.

Home Page

Web site

Web page

HTML (Hypertext Mark Up Language)

The set of special instructions (called tags or markups) that are used to specify document structure, formatting, and links to other multimedia documents.

A special text file which is read by your browser and displayed as a formatted Web page.

New standards for Web page creation include DHTML and XML which allow for even more dynamic presentations

Hyperlinks• Hyperlinks are connections to

other documents or web pages that contain related information; a word or phrase in one document becomes a connection to a document in a different place.

• One of the most commonly-used means of navigating the Web. They are links to specific URLs which simply means they take you from page to page.

• Most anything on a Web page can be a link but the most obvious is underlined text.

Web Site

• The location on a particular computer on the web that has unique address (URL)

• The location of a computer somewhere on the internet.

• A website is composed of a web page or collection of related web pages.

Home Page

Web site

Web page

Home Page

Home Page is the first page or main page of the web site. Normally homepage is

located in pub/index.html

Home Page

Web site

Web page

Web Server

A web server is a computer to store web sites that delivers requested web pages to a browser.

Web Browser

The key to the World Wide Web is your browser

A browser is software that enables users to locate and view web pages and to jump from one page to another

Things that are used to identify the resources on the Internet

Resource Identification

Telephone Number 6602-300-4543

House Address1234 Ramkhamhaeng Rd. BKK 10240

TCP/IP

• TCP/IP is the communications protocol that uses packet switching to facilitate the transmission of messages over the Internet.

• It actually consists of two protocols:– Transmission Control Protocol (TCP)– Internet Protocol (IP)

• With packet switching, messages are separated into small units called packets.

• Packets contain – Information about the sender and the receiver, – the actual data being sent– Information about how to reassemble the packets in order to reconstruct

the original message.• Packets travel along the network separately, based on their final

destination, network traffic, and other network conditions.• When the packets reach their destination, they are reassembled in the

proper order.

IP Address• Internet Protocol Address uniquely identifies every

computer and device connected to the internet.• Four set of numbers between 0-255 separated by

decimals.Eg. 168.120.15.198

• Similar to street no. and house no.

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Solution for IP Insufficiency

Dynamic IP Address

• Each time you connect to your ISP, it assigns your computer a new IP address, called a dynamic IP address.

• When you request data from the internet, it is transmitted to your computer’s IP address.

• When you disconnect, your provider frees up the IP address you were using and reassigns it to another user.

• A static IP address remains constant each time a person logs on to the internet.

IPv6

The IPv6 that uses a 128-bit system will hold 340-undecillion (34, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000)

This number is so vast that there are more unique ip addresses than stars in the universe, as we know it.

Domain Name

• Domain names typically identify who owns that computer and either the type of entity (such as a school, commercial business, government).

• A period separates the different parts of a domain name. • The rightmost part of the domain

name(beginning with the rightmost period) identifies the type of the organization or its location and is called the top-level domain (TLD).

Types of TLD

1. Type of entity: there were seven original types with three letters.

gov, com, net, edu, org, mil, int

2. Country of entity: with two-letter code

• .aero - for the air transport industry

• .biz - for business use

• .cat - for Catalan language/culture

• .com - for commercial organizations, but unrestricted

• .coop - for cooperatives

• .edu - for post-secondary educational establishments

• .gov - for governments and their agencies in the United States

• .info - for informational sites, but unrestricted

• .int - for international organizations established by treaty

• .jobs - for employment-related sites

• .mil - for the US military

• .mobi - for sites catering to mobile devices

• .museum - for museums

• .name - for families and individuals

• .net - originally for network infrastructures, now unrestricted

• .org - originally for organizations not clearly falling within the other gTLDs, now unrestricted

• .pro - for certain professions

• .tel - for services involving connections between the telephone network and the Internet (added March 2, 2007)

• .travel - for travel agents, airlines, hoteliers, tourism bureaus, etc.

• The following gTLDs are in the process of being approved, and may be added to the root nameservers in the near future:

• .asia - for the Asian community

• .post - for postal services

• .geo - for geographically related sites

• .cym - for Welsh language/culture

ICANN

(Internet Corporation for Assigned Names and Numbers)

the non-profit organization responsible for Internet IP address allocation and domain name management.

How does the Internet know that which domain name associate to which IP?

DNS

Domain Name Service It translate domain name to IP address.

URL Uniform Resource Locater (URL) is a string of characters

that points to a specific piece of information anywhere on the web.

The URL is the website’s unique address A URL defines the web address of the target HTML

document.

The format of a URL is:<protocol>://<domain name>/<directory path>/<file name>

E.g. http://www.scitech.au.edu/~chokdee/index.htm

Protocol: http://Domain name: www.scitech.au.eduDirectory name: chokdeeFile name: index.htm

1. Protocol

• Defines the rules and format to be used for the type of service

• Example– fetching a web page (HyperText Transfer

Protocol - http) – performing a file transfer (File Transfer Protocol

- ftp).

• http is the protocol or communication standard to transfer information on the web.– It allows browsers to connect with web servers

2. Domain Name

A domain is simply a location on the internet (web server).www.s-t.au.edu is the fully qualified domain name that uniquely identifies the S&T AU web server.

– www is the name of the host computer which is operating as a web server within the s-t.au.edu domain

– s-t indicates this is the S&T domain – au indicates this is the Assumption University

domain which the S&T domain resides – edu (education) is the second level domain

within which the AU domain resides

3. Directory Path

/subjects/information/ identifies the directory path to the file

4. Document File Name

index.html identifies the filename of the target document

How do we browse a website?

DNS

AU Web ServerComputer’s Browser

Mail Sever

ISP

http://www.au.ac.th

202.6.101.225

202.6.101.225

Get index.html

HTML File

Web Sever

End: Resource Identification

Providers on the internet

Internet Service Provider

ISP – also called access providers – are businesses or other organizations that provide Internet access to others, typically for a fee.

Internet Content Provider

• It supplies the information that is available through the Internet.

• Internet content providers can be commercial businesses, nonprofit organizations, educational institutions, individuals, and more.

• Ex: A television network, newspaper, music publisher.– An individual who publishes his opinion on

various subjects to an online journal or blog.

Application Service Provider

ASP –are companies that manage and distribute software based services to customers over the Internet.

Instead of providing access to the Internet like ISPs do, ASPs provide access to software applications via the Internet.

ASPs rent software access to companies or individuals – typically, customers pay a monthly or yearly fee to use the applications.

End: Providers on the Internet