Re: Web Server Architecture -- help please

coakleyj_at_hotmail.com wrote in message <7un5i1$18n$1_at_nnrp1.deja.com>...

>I've a quick question as to why many
>technical architect diagrams make a distinction
>between web servers and application servers (somtimes
>seperated by a firewall).
>
>This is totally confusing me!

I agree. A web server can be two tier - normal client server stuff. The browser is the client, the web server is a stateless server.

>How does this apply to Oracle technology

This is where the picture become a bit less clear. A web server can in turn be a client. This is how CGIs (Common Gateway Interface) and associated standards (ISAPI, NSPAI, WinCGi etc) work. They allow the web server to be the client and thru this interface communicate with another server, like an Oracle database. An Oracle database can in turn be a client of another database. The borders between client and server is becoming blurred as functionality and flexibility increases.

So when does two tier become three tier? And does it really matter? Leaving purist architectural viewpoints aside, whatever works for you, works - irrespective of the architectural label you want to stick to it. :-)

>After all Oracle Application
>Server has a web listener (i.e web server) inherent
>within it. So, is it normal to have seperate web servers
>and application servers (seperated by firewalls) when
>using Oracle technology.

This is if you assume that your "web server" and application server are separate entities. It does not need to be. Remember that a web server is just a very simplistic stateless server that supports a couple of commands (i.e. HTTP) for delivering files (HTML, video, audio etc). Whether you use the HTTP protocol as the interface to your server (database, application, whatever) to deliver other "forms of information" is a question of implementation and not architecture. Where to put a firewall is also a question of security and not architecture IMO. The architecture should not dictate, your requirements should. IOW, from your requirements there will "flow" an architecture. And if that means building an architecture that conflicts with the purist view of the traditional client-server architectures, then so be it. :-)

My thoughts anyway..

regards,
Billy Received on Fri Oct 22 1999 - 03:25:09 CDT