Comparison of ASP.net request processing process of IIS5, IIS6 and IIS7

Asp. NET is a very powerful platform for building Web applications that provides great flexibility and capacity to build all types of Web applications.

The vast majority of people are familiar with high-level frameworks such as WebForms and WebServices, which are at the highest level in the ASP.net hierarchy.

This article is compiled from a variety of Microsoft-exposed documents, by comparing the IIS5, IIS6, IIS7 of the three generations of IIS to the request process, let us familiarize ourselves with the underlying mechanism of ASP.net and request is how to transfer from a Web server to a asp.net runtime. By understanding the underlying mechanism, we can have a deeper understanding of asp.net.

The asp.net request processing process for IIS 5

Explanation of the diagram:

One notable feature of IIS 5.x is the separation of Web server and real asp.net application. IIS running as Web server runs on a process named InetInfo.exe, InetInfo.exe is a native Executive, not a hosted program, and our real asp.net Application is run on top of a Worker process called aspnet_wp, which loads the CLR when the process is initialized, so this is a managed environment.

ISAPI: An application that can handle various suffix names. The ISAPI is a shorthand for the following words: Internet server application programe Interface, Internet Servers application interface.

Features of IIS 5 mode:

1, first, the same host at the same time can only run a aspnet_wp process, each based on the virtual directory asp.net application corresponding to a application Domain, That is, each application is running in the same worker process, and the isolation between application is based on application domain rather than process based.

2. Second, ASP.net ISAPI is responsible for creating aspnet_wp Worker process and monitoring the process, if aspnet_wp performance is lowered to a set lower limit, asp.net The ISAPI will be responsible for ending the process. After the aspnet_wp is finished, subsequent request will cause the ASP.net ISAPI to recreate the new aspnet_wp Worker Process.

3. Finally, since IIS and application are running in their respective processes, communication between them must be based on a specific communication mechanism. Essentially, the communication between the Inetinfo process of IIS and the worker process is communication between different processes of the same machine (local interprocess communications), which is considered in performance, They adopted a communication mechanism based on named pipe. Communication between the ASP.net ISAPI and the worker process is implemented through a set of pipe between them. Also in the performance, ASP.net ISAPI passes the request to the worker process and obtains the response asynchronously, but the worker process is synchronized to ASP.net The ISAPI obtains some server-based variables.

IIS6 's asp.net request processing process