N-tier
application architecture provides a
model for
developers so they can create a
flexible and reusable
application. Because an application is broken down into
tiers,
developers only have to
modify or add a specific
layer, rather than rewriting the entire application over if they decide to
upgrade or change technologies. In the term "N-tier," "
N" implies any number (like 2-tier, or 4-tier or any number of tiers used in your architecture). Application architectures are part of Layer 7 of the
OSI reference model.
For more about application architecture, see this article:
http://www.15seconds.com/issue/011023.htm
For a diagram, see this page:
picture:http://www.webopedia.com/img/app.arch.gif