So we have this concept of the Internet being made up of nodes, with machines of all types making up the network. Messages are passed around as packets using the Internet Protocol (with unique identifiers called IP addresses). Communication between two nodes is controlled using the Transmission Control Protocol. Packets find their destination because of the Internet Protocol. The MESSAGE gets from London to Beijing and is re-assembled in the correct order thanks to Transmission Control Protocol.
The overall control of the message and the way it gets from sender to recipient is thanks to TCP.
Server’s job is to sit around all day, listening for communication requests. Client’s job is to make requests. Some servers will satisfy requests indiscriminately, others require authentication. It depends upon the service being provided.
Once connected the two software applications use yet another protocol called the Hyper-Text Transfer Protocol, that describes the rules for exchanging html documents. This involves a series of GET and POST methods. The browser software has the job of rendering a web page according to the instructions contained in the HTML code The server simply has the job of dishing out html files whenever it received GET requests.
Various standards taken from four different pages, it should be noted that regardless of the standard they are referring to, they ARE declaring which standard the document complies to and therefore gives the browser a better opportunity to interpret the html correctly (as the developer intended).
Ask the student to find out what the current standard is and when it was introduced. What percentage of sites do they think conform to the standard? Do all browsers correctly interpret the standard? Do any
Founded in 1994 by Tim Berners-Lee W3C is an independent body concerned with the design of new web technologies and the release of relevant standards Contributions from 100s of dedicated researchers and engineers
TCP / IP Services and Standards
Website Design and
Services and Standards
Transmission Control Protocol
ME SS AG E
Client – Server model
“Server” – because it provides a service.
“Client” – because they take advantage of the service.
Hyper-Text Transfer Protocol
Computer BComputer A
<<<< html <<<<
HTTP protocol shared between two applications.
Uniform Resource Locator
– The protocol used.
– Type of service requested.
– The domain name (IP address).
– Location (on the host) of the document.
– Name of the document (message).
Services (and their provider)
Web content (web Server)
File transfer (ftp Server)
Chat (irc Server)
Email (smtp and pop server)
Applications (database servers)
<!DOCTYPE html PUBLIC "-//W3C//DTD
XHTML 1.0 Transitional//EN"
<!DOCTYPE HTML PUBLIC "-//IETF//DTD
What is the current standard?
What percentage of sites conform
to the standard?
Do all browsers correctly
implement the standard?
What is the World Wide Web
Founded in 1994 by Tim Berners-Lee
Design new technologies