Again and again I read somethings about the osi-model without knowing it. This cause that I can not understand the things correctly. So I will describe the osi-model hoping to remember it and the different layers:

The user:
– layer 8: the user (this layer is more or less a joke and does not exists)

The application:
– layer 7: application layer (http, ftp, …)
– layer 6: communication layer or presentation layer (http, ftp, …)
– layer 5: session layer (http, ftp, …)

The transport:
– layer 4: transport layer (TCP/UDP, …)
– layer 3: network layer (IP, …)
– layer 2: data link layer (MAC, …)
– layer 1: physical layer (ethernet, …)

Layer 1 to 4 will manage the transport of all packages. Layer 5 to 7 provide the application-data-flow. Layer 8, which does not exists is the user. If it is a layer-8-problem than the it is the faul of the user.