In the OSI model, what is the top level layer called?

The top level layer in the OSI model is called the Application layer. This layer is responsible for providing network services to end-user applications. It acts as an interface between the network and the applications that run on a user's device. The Application layer serves as the window for users and application processes to access network services, facilitating functions such as file transfers, email, and web browsing.

In the context of the OSI model, it is important to note that the layers below it, such as the Transport and Session layers, focus on data transport and session management respectively, but they do not interact directly with end-user applications. The Application layer's role is crucial because it directly supports user-level functions and defines the protocols and standards for application-level connectivity, making it fundamental to the overall networking process.