1. LECTURE 1 (ETCS-308) Subject teacher : Ms. Gunjan Beniwal
WEB ENGINEERING
LECTURE (ETCS-308)
Subject teacher : Ms. Gunjan Beniwal

2. WEB ENGINEERING
Web Engineering is the application of systematic, disciplined and quantifiable approach for development, operation and maintenance of web-based applications.
It focuses on the methodologies, techniques and tools that are the foundation of web application, development and which support their design, development and evaluation.

3. Contents History of internet Basic Internet Protocols
World Wide Web Consortium
Html

4. History of internet
The internet traces its roots from the project of U.S. Department of Defense then named as Advanced Research Projects Agency or (ARPA).
In 1969, ARPANET project was intended to support research on computer network.

5. History of internet
1969:. The first message was “LO,” which was “LOGIN”
1972: network
1973: The term Internet was born.
1974: The first Internet Service Provider (ISP) was born
1974: design of TCP.
1976: first .
1979: USENET

6. History of internet
1981: networking services to university computer scientists started.
1982: Transmission Control Protocol (TCP) and Internet Protocol
1983: The Domain Name System 
1984: cyberspace
1985: Symbolics.com the website
1986: NSFNET goes online to connected supercomputer

7. History of internet
1987: The number of hosts on the Internet exceeds 20,000. Cisco ships its first router.
1989: World.std.com becomes the first commercial provider of dial-up access to the Internet
1990: Tim Berners-Lee, a scientist at CERN, the European Organization for Nuclear Research, develops HyperText Markup Language (HTML).
1991: World Wide Web introduced to the public.
1992: The first audio and video are distributed over the Internet.

8. History of internet
1993: The number of websites reaches 600 and the White House and United Nations go online.
1994: Netscape Communications was born.
1995: The original NSFNET backbone is decommissioned as the Internet’s transformation to commercial enterprise

9. History of internet 1996: The browser war
1997: Netscape announces that its browser will be free.
1998: The Google search engine was born
1999: Peer-to-peer file sharing
2000: Web sites got denial of service attack highlighting the vulnerability of the Internet

10. Basic Internet Protocols
For computers to communicate with each other, standard methods of information transfer and processing are required and these are referred to as “protocols”.
Some common protocols are:
TCP, IP, UDP, FTP, TFTP, Telnet, HTTP, etc.

11. TCP/IP TCP/IP is actually a combination of two protocols
It defines how electronic devices (like computers) should be connected over the Internet, and how data should be transmitted between them.

12. 1.Transmission Control Protocol (TCP)
TCP is responsible for breaking data down into small packets before they can be sent over a network, and for assembling the packets again when they arrive.
It is a connection oriented protocol and offers end- to-end packet delivery. It acts as back bone for connection.
TCP offers:
Stream Data Transfer.
Reliability.
Efficient Flow Control
Full-duplex operation

13. 2. Internet Protocol
IP takes care of the communication between computers. It is responsible for addressing, sending and receiving the data packets over the Internet.
it is connectionless and unreliable protocol. It ensures no guarantee of successfully transmission of data.
In order to make it reliable, it must be paired with reliable protocol such as TCP at the transport layer

14. 3. User Datagram Protocol (UDP)
UDP is connectionless and unreliable protocol. It doesn’t require making a connection with the host to exchange data. Since UDP is unreliable protocol, there is no mechanism for ensuring that data sent is received.
UDP is used by the application that typically transmit small amount of data at one time.
It provides protocol port used i.e. UDP message contains both source and destination port number, that makes it possible for UDP software at the destination to deliver the message to correct application program.

15. File Transfer Protocol (FTP)
It is a standard network protocol used to transfer computer files between client and server on computer networks.
FTP creates two processes such as Control Process and Data Transfer Process at both ends i.e. at client as well as at server.
FTP establishes two different connections: one is for data transfer and other is for control information.
FTP uses port 21 for the control connection and Port 20for the data connection.

16. FTP

17. 5. Trivial File Transfer Protocol (TFTP)
Trivial(unimportant) File Transfer Protocol is also used to transfer the files but it transfers the files without authentication. Unlike FTP, TFTP does not separate control and data information. Since there is no authentication exists, TFTP lacks in security features therefore it is not recommended to use TFTP.

18. Telnet
Telnet is a protocol used to log in to remote computer on the internet. There are a number of Telnet clients having user friendly user interface. The following diagram shows a person is logged in to computer A, and from there, he remote logged into computer B.

19. 7. Hyper Text Transfer Protocol (HTTP)
HTTP is a communication protocol. It defines mechanism for communication between browser and the web server.
It is also called request and response protocol because the communication between browser and server takes place in request and response pairs.

20. HTTP Request HTTP Response
HTTP request comprises of lines which contains:
Request line
Header Fields
Message body
Key Points
The first line i.e. the Request line specifies the request method i.e. Get or Post.
The second line specifies the header which indicates the domain name of the server from where index.htm is retrieved.
HTTP Response
Like HTTP request, HTTP response also has certain structure. HTTP response contains:
Status line
Headers

21. An HTTP conversation
Client
Server OK
Send page or error message
I would like to open a connection
GET <file location>
Display response
Close connection
HTTP is the set of rules governing the format and content of the conversation between a Web client and server

22. World Wide Web Consortium
The World Wide Web Consortium (W3C) is the main international standards organization for the World Wide Web .
Founded and currently led by Tim Berners-Lee
The consortium is made up of member organizations which maintain full-time staff for the purpose of working together in the development of standards for the World Wide Web.
The W3C also engages in education and outreach, develops software and serves as an open forum for discussion about the Web.

23. How the Web Works? WWW use classical client / server architecture*
07/16/96
How the Web Works?
WWW use classical client / server architecture
HTTP is text-based request-response protocol
HTTP
Page request
HTTP
Server response
Server running Web Server Software (IIS, Apache, etc.)
Client running a Web Browser
(c) 2007 National Academy for Software Development - All rights reserved. Unauthorized copying or re-distribution is strictly prohibited.*

24. HTML It was first developed by Tim Berners-Lee in 1990.
It is used to create electronic documents (called pages) that are displayed on World Wide Web.
Each page contains a series of connections to other pages called hyperlinks.
Every page on internet is written using one version of HTML code or another.

25. HTML Versions Version Year HTML 1991 HTML 2.0 1995 HTML 3.2 1997
XHTML
HTML

26. What is a Web Page? Web pages are text files containing HTML*
07/16/96
What is a Web Page?
Web pages are text files containing HTML
HTML – Hyper Text Markup Language
A notation for describing
document structure (semantic markup)
formatting (presentation markup)
The markup tags provide information about the page content structure
(c) 2007 National Academy for Software Development - All rights reserved. Unauthorized copying or re-distribution is strictly prohibited.*

27. *
07/16/96
Creating HTML Pages
An HTML file must have an .htm or .html file extension
HTML files can be created with text editors:
NotePad, NotePad ++, PSPad
Or HTML editors (WYSIWYG Editors):
Microsoft FrontPage
Macromedia Dreamweaver
Netscape Composer
Microsoft Word
Visual Studio
(c) 2007 National Academy for Software Development - All rights reserved. Unauthorized copying or re-distribution is strictly prohibited.*

28. HTML Structure HTML is comprised of “elements” and “tags”*
07/16/96
HTML Structure
HTML is comprised of “elements” and “tags”
HTML describes structure using two main sections: <head> and <body>
<html>
<head>
<title>Page title</title>
</head>
<body>
<h1>This is a heading</h1>
<p>This is a paragraph.</p>
</body>
</html>
(c) 2007 National Academy for Software Development - All rights reserved. Unauthorized copying or re-distribution is strictly prohibited.*

29. First HTML Page: Tags Opening tag Closing tag <!DOCTYPE HTML>*
07/16/96
First HTML Page: Tags
<!DOCTYPE HTML>
<html>
<head>
<title>My First HTML Page</title>
</head>
<body>
<p>This is some text...</p>
</body>
</html>
Opening tag
Closing tag
An HTML element consists of an opening tag, a closing tag and the content inside.
(c) 2007 National Academy for Software Development - All rights reserved. Unauthorized copying or re-distribution is strictly prohibited.*

30. First HTML Page: Header*
07/16/96
First HTML Page: Header
HTML header
<!DOCTYPE HTML>
<html>
<head>
<title>My First HTML Page</title>
</head>
<body>
<p>This is some text...</p>
</body>
</html>
(c) 2007 National Academy for Software Development - All rights reserved. Unauthorized copying or re-distribution is strictly prohibited.*

31. First HTML Page: Body HTML body <!DOCTYPE HTML> <html>*
07/16/96
First HTML Page: Body
<!DOCTYPE HTML>
<html>
<head>
<title>My First HTML Page</title>
</head>
<body>
<p>This is some text...</p>
</body>
</html>
HTML body
(c) 2007 National Academy for Software Development - All rights reserved. Unauthorized copying or re-distribution is strictly prohibited.*

32. First HTML Page test.html <!DOCTYPE HTML> <html>*
07/16/96
First HTML Page
test.html
<!DOCTYPE HTML>
<html>
<head>
<title>My First HTML Page</title>
</head>
<body>
<p>This is some text...</p>
</body>
</html>
(c) 2007 National Academy for Software Development - All rights reserved. Unauthorized copying or re-distribution is strictly prohibited.*

33. Thankyou