Architechture of Katana based application:

There are four layers of Katana based applications:

1. Application layer
- Application layer is the client. e.g. your website built in Asp.net MVC , or console or windows application. This is used by end user and has nothing specific to OWIN.
2. Middle layer
- This is a set of components . These components are built using OWIN specifications. There can be more than one component in this layer. They can form a pipeline or a chain of components. These components are executed before request reaches the server. These components can be added or removed through code. These components can be like Web API or ASP.Net Identity or SignalR.
3. Server Layer
- Server layer receives the request and network related task are performed like opening the sockets Katana has two server components:
1. Microsoft.Owin.Host.SystemWeb
: Looks into IIS through an HTTP handler and module. If IIS is to be used as your host this should be used.
2. Microsoft.Owin.host.HttpListener
: It is used if we need our own host(self-hosting)
4. Host Layer
- Overall environment for the application is provided by this layer. There are 3 ways to host Katana based applications IIS : Use IIS as a host. IIS acts as a host also as a server OwinHost.exe: Lightweight host use to host application CustomHost : If above two do not meet our requirment we can go with custom host too.