Page Parsing in WSS 3.0 and WSS 2.0

To start with the WSS 2.0  page parsing mechanism , WSS 2.0 was integrated with ASP.NET 1.1 using the ISAPI filter. Request from the client is directly routed to ISAPI filter before ASP.NET  mechanism in WSS 2.0 .This approach might not be the ideal  as its not possible to leverage complete funcionality of ASP.NET .

This Has been very well handled in WSS 3.0 where the ISAPI filter is removed and the request routing is done using HttpModule and HttpHandler .Advantage of this approach is that the request is handled by the ASP.NET runtime before it is forwarded to WSS processing mechanism.

 

To get insight details on this please check the following article by "Ted Pattison"
http://msdn.microsoft.com/msdnmag/issues/06/07/WSS30Preview/default.aspx