Beginning JSP JSF and Tomcat Web Development From Novice to Professional.pdf

You’ll find a lot of material on how to write web pages both on the Internet and in print.
But a book on JSP wouldn’t be complete without a chapter explaining what makes the
WorldWide Web work as it does. We’ll explain the key concepts while covering as much
ground as possible.
Web Pages in General
For your browser to render a web page correctly, it must be able to do the following:
• Communicate with the server, or servers,where the page content is stored: This
means the browser must support the necessary protocols, and it must be configured
correctly and include the proper addressing.
• Interpret the page syntax correctly and act on it as expected by the page designer:
This means using the same standards that are used on the server and conforming
to them.
• Include the plug-ins and have access to the facilities needed to process all compo-
nents of the page: For example, the browser must be able to render Adobe Shockwave
animations or whatever else the page designer has included on the page.
Before going into the details of how you structure and develop web pages, we’ll provide
some background information to put everything into the right perspective.
The Protocols
A data-communication protocol is a standardized set of rules that computers must follow to
be able to communicate with each other. The protocol rules define the format of the data
packets being transferred and the way in which the exchange takes place.
To make this complex process more manageable, the functionality necessary to move
data across networks is broken down into layers organized into protocol stacks, or protocol
suites. Higher layers can perform more general and complex tasks by relying on the services
of the lower layers. Computers communicate across the Internet by means of the Internet
protocol stack, which consists of five layers. Starting from the top, these layers are applica-
tion, transport, network, link, and physical.