ASP.NET - Web Application Architecture

Web Application works in Client/Server architecture. On Client side you need a web browser that understands HTML and on Server side you need a Web Server to host the application

ASP .NET Web application runs under Microsoft Internet Information Service (IIS).

Let's understand how a request is being handled in web application.

When a user requests for a URL in a web browser, the request goes to the web server (in our case it is IIS) through internet using HTTP protocol (Hyper Text Transfer Protocol). Once the web server, receives the requests it process that request (For example if the data need to be retrieved from database, IIS contacts the application DLL to get the data from database) and send the HTML content back to the browser.

Protocol - Set of standard rules, that describes how two or more items communicate over internet.

ASP .NET - Web Application Introduction

A web application is an application that is accessed by users by using a web browser. Example of web browsers:

• Microsoft Internet Explorer (IE)
• Google Chrome
• Mozilla Firefox
• Apple Safari
• Netscape

There are many frameworks to build a web application and ASP.NET is the one among them, that is created by Microsoft to build dynamic data driven web application and web services. ASP .Net is introduced in 2002 and it is the successor of the Classic ASP. 

There are many advantages of having a web application over a desktop application (Example of desktop application is Microsoft Office).

• Easy Deployment: Desktop application need to be deployed in each of the users's computer who need the access to the application, so lets say if there are 5000 user which requires the same application it has to be installed in 5000 computers. On the other hand a web application is deployed in a web server and accessed using a web URL in a web browser,  and all the 5000 users can access that if they have a wen browser which understand HTML.
• Ease of Maintenance/Support/Patch: If a bug fix is done in the application, in case of desktop application patch has to be deployed to ease user's system where as in case of web application the patch is only need to be applied to the Web Server where the application is being hosted. 
• No additional software required to access the web application as long as user has the web browser that can understand HTML, in place of Desktop application each user need to have the application installed in their computers.
• Cross Platform: In case of desktop application, if the application is developed in Windows platform it can only be accessed in windows OS, to make the application accessible in other platforms it has to be re developed in those platforms, where as in case of web application irrespective of which platform the application is being developed, it can be accessible to the user if user has a browser that understands HTML.

Framework - In simple terms framework is a collection of classes.