tcp / ip services and standards
DESCRIPTION
Learn about TCP / IP - What is it and how does it work?TRANSCRIPT
Website Design and Construction
Services and Standards
The Internet
London
Beijing ME
SS
AG
E
Internet Protocol (IP)
London
Beijing
E
Transmission Control Protocol (TCP)
London
Beijing ME SS AG E
Client – Server model
Server
Client
Client
Client
“Server” – because it provides a service.
“Client” – because they take advantage of the service.
Hyper-Text Transfer Protocol (HTTP)
Computer B Computer A
Browser (client)
Web Server (server)
Connection
<<<< html <<<<
HTTP protocol shared between two applications.
Uniform Resource Locator
Describes– The protocol used.– Type of service requested.– The domain name (IP address).– Location (on the host) of the document.– Name of the document (message).
http://www.hct.ac.ae/courses/higherdiploma.html
http://webmail.hct.ac.ae/index.html
ftp://ftpservername.hct.ac.ae/myfiles/plan.doc
Services (and their provider)
Web content (web Server) File transfer (ftp Server) Chat (irc Server) Email (smtp and pop server) Applications (database servers)
Web Servers and Web Browsers
Browser Web Server
The Internet
<htklsdf> <htm> <ht><wer ><asdf< asd f>f
<htklsdf> <htm> <ht><wer ><asdf< asd f>f
<htklsdf> <htm> <ht><wer ><asdf< asd f>f
<htklsdf> <htm> <ht><wer ><asdf< asd f>f
<htklsdf> <htm> <ht><wer ><asdf< asd f>f
<htklsdf> <htm> <ht><wer ><asdf< asd f>f
<htklsdf> <htm> <ht><wer ><asdf< asd f>f
<htklsdf> <htm> <ht><wer ><asdf< asd f>f
<htklsdf> <htm> <ht><wer ><asdf< asd f>f
<htklsdf> <htm> <ht><wer ><asdf< asd f>f
<htklsdf> <htm> <ht><wer ><asdf< asd f>f
<htklsdf> <htm> <ht><wer ><asdf< asd f>f
<htklsdf> <htm> <ht><wer ><asdf< asd f>f
<htklsdf> <htm> <ht><wer ><asdf< asd f>f
<htklsdf> <htm> <ht><wer ><asdf< asd f>f
<htklsdf> <htm> <ht><wer ><asdf< asd f>f
Parse
<htklsdf> <htm> <ht><wer ><asdf< asd f>f
Client side Server side
Render
Web Servers & Web Browsers
Many devices = Many browsers
– Internet Explorer– Netscape Navigator– Mozilla FireFox– Opera– Lynx– Konqueror
Web Servers & Web Browsers
Many browser = problems
– Differing interpretations of html pages– Browser specific tags! – Different fonts– Different screen resolutions– Different colour depths
Web Servers & Web Browsers
Problems solved by STANDARDS– Language standards (HTML)– Protocol standards– Colour representation standards– ….
Standard USE of LANGUAGES
Example
<img src=“images/logo.gif”>
<img src=“images/logo.gif” alt=“Company logo - a globe”>
…without images displayed.
HTML <!DOCTYPE html PUBLIC "-//W3C//DTD
XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN">
What is the current standard?
http://www.w3c.org
What percentage of sites conform to the standard?
Do all browsers correctly implement the standard?
What is the World Wide Web Consortium (W3C)? Founded in 1994 by Tim Berners-Lee
Independent body
Define standards
Design new technologies