Transcript Sec 3 Slides

HTTP
How the Internet servers and clients
communicate.
WHAT IS HTTP?

Hyper-Text Transfer Protocol
“When you enter a URL in your browser, this
actually sends an HTTP command to the Web
server directing it to fetch and transmit the
requested Web page.”
WHAT IS GOING ON WHILE I AM
SURFING THE NET ?
When clicking on an hypertext link,
you are transferring an URL to your
browser. From this URL, your browser
knows which server to contact and
what file to ask for.
Instead of sending the data as
plaintext, the information is first
encrypted and then sent, improving
the overall security.
WHAT IS GOING ON WHEN I AM SURFING
THE NET?
•
The request would be
•
HEAD / HTTP/1.1
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, */*
Accept-Language: fr
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 5.0; Windows 98;
DigExt)
Host: www.google.com:80
Connection: Keep-Alive
•
The Response would be
•
HTTP/1.1 302 Found
Location: http://www.google.fr/
Cache-Control: private
Set-Cookie:
PREF=ID=fe069539fd6bfe93:TM=1195177603:LM=1195177
603:S=BT2pymOBV6DF1vyq; expires=Sun, 15-Nov-2009
01:46:43 GMT; path=/; domain=.google.com
Content-Type: text/html
Server: gws
Content-Length: 0
Date: Fri, 16 Nov 2007 01:46:43 GMT
WHERE DOES HTTP FIT IN
COMMUNICATION PROTOCOLS?
Open Systems Interconnection Model (OSI) is the
standard model for network architectures.
 OSI is the standard reference model to explain how to
design a network.
 Transmission Control Protocol/Internet Protocol
(TCP/IP)
 TCP/IP is the primary communications protocol of the
internet, responsible for moving and verifying the
correct deliver of data from sender to receiver.

Image courtesy of mdm-zone.com
WHERE DOES HTTP FIT IN
COMMUNICATION PROTOCOLS?
HTTP
HTTP
HTTP is part of the transport layer; it enables
communication between the client and server.
It is also applied in the application layer when the
user initially communicates with the server.
Image Courtesy of mdm-zone.com
SECURE STORAGE
 HTTPS
Short for Hypertext Transfer Protocol over Secure
Socket Layer, HTTPS is a secure method of
accessing web page information and/or sending
information across a web page. Instead of sending
the data as plaintext, the information is first
encrypted and then sent, improving the overall
security.
 HTTPS uses port 443 to transfer its information.
 HTTPS is the same as HTTP/1.1 and is defined in
RFC 2616.

FIND OUT WHAT YOUR FAVORITE WEBSITE AND
YOUR BROWSER ARE SAYING TO EACH OTHER!

HTTP Header Reader
WHO IS IN CHARGE OF REGULATING
HTTP?

The W3C is in charge of regulating the Internet.
They have published the current standardized
format for HTTP.
VERSIONS OF HTTP PASSED BY W3C

HTTP/0.9 was the first version of the HTTP

HTTP/1.0 is specified in RFC 1945

HTTP/1.1 is specified in RFC 2616
WHO CREATED HTTP?
Many people try to claim responsibility for the creation of the internet…
WHO CREATED HTTP?
But, it was mostly this guy;Tim Berners Lee. He created http and some
of the basic protocols that make the up the world wide web.
WHO CREATED HTTP?
Lee is an English developer who invented the
world wide web with his associate Robert Cailiau.
 In 1980 he started projects based on the concept
of hypertext to facilitate sharing and updating
information between researchers. His work
progressed and evolved into HTTP as we know it
today.
 He founded W3C in 1994 to help improve the
quality of the web.
 He’s kind of a big deal.
