world wide web

Disclaimer:This presentation is prepared by trainees of
baabtra as a part of mentoring program. This is not official
document of baabtra –Mentoring Partner
Baabtra-Mentoring Partner is the mentoring division of baabte System Technologies Pvt .
Ltd

WORLD WIDE WEB

Ashwin Anand V
Email:ashwinanand99@gmail.com
Facebook id:ashwinanand99@gmail.com

WWW History

• 1989-1990 – Tim Berners-Lee invents the World
Wide Web at CERN
– Means for transferring text and graphics
simultaneously
– Client/Server data transfer protocol
• Communication via application level protocol
• System ran on top of standard networking
infrastructure

– Text mark up language
• Not invented by Bernes-Lee
• Simple and easy to use
• Requires a client application to
render text/graphics

What Is the World Wide Web?
The world wide web (web) is a network of
information resources. The web relies on three
mechanisms to make these resources readily
available to the widest possible audience:
1. A uniform naming scheme for locating resources on
the web (e.g., URIs).
2. Protocols, for access to named resources over the
web (e.g., HTTP).
3. Hypertext, for easy navigation among resources (e.g.,
HTML).

TYPES OF WEB
• Public web

• Invisible web/deep web

WWW Structure
• Clients use browser application to send URIs via
HTTP to servers requesting a Web page
• Web pages constructed using HTML and consist of
text, graphics, sounds plus embedded files
• Servers respond with requested Web page
• Client’s browser renders Web page returned by
server
– Page is written using HTML
– Displaying text, graphics and sound in browser
– Writing data as well
• The entire system runs over standard networking
protocols (TCP/IP, DNS,…)

Standard Generalized Markup
Language (SGML)
• Based on GML (generalized markup
language), developed by IBM in the 1960s
• An international standard (ISO 8879:1986) defines
how descriptive markup should be embedded in a
document
• Gave birth to the extensible markup language
(XML), W3C recommendation in 1998

SGML Components

SGML documents have three parts:
• Declaration: specifies which characters and
delimiters may appear in the application
• DTD/ style sheet: defines the syntax of markup
constructs
• Document instance: actual text (with the tag) of the
documents
More info could be found:
http://www.W3.Org/markup/SGML

HTML Background
• HTML was originally developed by Tim Berners-Lee
while at CERN, and popularized by the Mosaic
browser developed at NCSA.
• The Web depends on Web page authors and vendors
sharing the same conventions for HTML. This has
motivated joint work on specifications for HTML.
• HTML standards are organized by W3C :
http://www.w3.org/MarkUp/

HTML Functionalities
HTML gives authors the means to:
• Publish online documents with headings, text, tables,
lists, photos, etc
– Include spread-sheets, video clips, sound clips,
and other applications directly in their documents
• Link information via hypertext links, at the click of a
button
• Design forms for conducting transactions with
remote services, for use in searching for information,
making reservations, ordering products, etc

Sample Webpage HTML Structure

<HTML>
<HEAD>
<TITLE>The title of the webpage</TITLE>
</HEAD>
<BODY> <P>Body of the webpage
</BODY>
</HTML>

HTML Structure

• An HTML document is divided into a head section
(here, between <HEAD> and </HEAD>) and a body
(here, between <BODY> and </BODY>)
• The title of the document appears in the head (along
with other information about the document)
• The content of the document appears in the body. The
body in this example contains just one paragraph,
marked up with <P>

HTML Hyperlink
<a href="relations/alumni">alumni</a>
• A link is a connection from one Web resource to
another
• It has two ends, called anchors, and a direction
• Starts at the "source" anchor and points to the
"destination" anchor, which may be any Web resource
(e.g., an image, a video clip, a sound bite, a program,
an HTML document)

Resource Identifiers

URI: Uniform Resource Identifiers
• URL: Uniform Resource Locators
• URN: Uniform Resource Names

Introduction to URIs
Every resource available on the Web has an address
that may be encoded by a URI
URIs typically consist of three pieces:
• The naming scheme of the mechanism used to
access the resource. (HTTP, FTP)
• The name of the machine hosting the resource
• The name of the resource itself, given as a path

URI Example

http://www.w3.org/TR
• There is a document available via the HTTP protocol
• Residing on the machines hosting www.w3.org
• Accessible via the path "/TR"

Protocols
Describe how messages are encoded and exchanged
Different Layering Architectures
• ISO OSI 7-Layer Architecture
• TCP/IP 4-Layer Architecture

ISO’s Design Principles
• A layer should be created where a different level of
abstraction is needed
• Each layer should perform a well-defined function
• The layer boundaries should be chosen to minimize
information flow across the interfaces
• The number of layers should be large enough that
distinct functions need not be thrown together in the
same layer, and small enough that the architecture
does not become unwieldy

TCP/IP Layering Architecture

• A simplified model, provides the end-to-end reliable
connection
• The network layer
– Hosts drop packages into this layer, layer routes
towards destination
– Only promise “Try my best”
• The transport layer
– Reliable byte-oriented stream

HTTP Basics
• Protocol for client/server communication
– The heart of the Web
– Very simple request/response protocol
– Relies on URI naming mechanism
• Three versions have been used
– 09/1.0 – very close to Berners-Lee’s original
– 1.1 – developed to enhance performance, caching,
compression
– 1.0 dominates today but 1.1 is catching up

HTTP Response Codes
• 1xx – Informational – request received, processing
• 2xx – Success – action received, understood, accepted
• 3xx – Redirection – further action necessary
• 4xx – Client Error – bad syntax or cannot be fulfilled
• 5xx – Server Error – server failed

Domain Name System
DNS (domain name service): mapping from domain
names to IP address
IPv4:
• IPv4 was initially deployed January 1st. 1983 and is
still the most commonly used version.
• 32 bit address, a string of 4 decimal numbers
separated by dot, range from 0.0.0.0 to
255.255.255.255.
IPv6:
• Revision of IPv4 with 128 bit address

Top Level Domains (TLD)
Top level domain names, .com, .edu, .gov and ISO 3166
country codes
There are three types of top-level domains:
• Generic Domains were created for use by the
Internet public
• Country code domains were created to be used by
individual country
• . arpa domain Address and Routing Parameter Area
domain is designated to be used exclusively for
Internet-infrastructure purposes

Registrars

• Domain names ending with .aero, .biz, .com, .coop,
.info, .museum, .name, .net, .org, or .pro can be
registered through many different companies (known
as "registrars") that compete with one another
• InterNIC at http://internic.net
• Registrars Directory:
http://www.internic.net/regist.html

• If this presentation helped you, please visit
our page facebook.com/baabtra and like it.
Thanks in advance.

• www.baabtra.com | www.massbaab.com |ww
w.baabte.com

world wide web

Empfohlen

Empfohlen

Weitere ähnliche Inhalte

Was ist angesagt?

Was ist angesagt? (20)

Ähnlich wie world wide web

Ähnlich wie world wide web (20)

Mehr von baabtra.com - No. 1 supplier of quality freshers

Mehr von baabtra.com - No. 1 supplier of quality freshers (20)

world wide web