I need to map TCP/IP protocols to the OSI model for some university test revision I am doing.
I was wondering if it is generally acceptable to assume any OSI Level 7, 6 and 5 protocol will be transferred directly into TCP/IP's Layer 4 (Application Layer).
Obviously with TCP/IP to OSI mapping, you have to use more common sense, such as MMS from TCP/IP Application would go to Presenation Layer.
The OSI and TCP/IP are different models and everything doesn't always line up perfectly in practice. In going from OSI to TCP/IP, everything above TCP (OSI Layers 5-7) is considered the Application layer (TCP/IP Layer 4). From TCP/IP to OSI there can be a lot of disagreement over what falls into each of layers 5-7.
To add to the complication there are protocols which span multiple layers, for example, Ethernet is both layer 1 AND 2 in the OSI model.
Yes. Both of the OSI and TCP/IP models are pretty old at this stage, and the TCP/IP model was created more specifically to "operate" with the IP protocol suite (the TCP/IP model slightly predates the OSI model). The OSI model was created by the ISO (International organization) and TCP/IP model was created by the U.S. and is maintained by the IETF. Even if TCP/IP didn't turn out to be the predominant protocol suite used on the Internet as we know it, with things like Moore's law and increasingly complex applications/protocols that can span multiple layers, the OSI model is becoming somewhat obsolete.
The reason why layers 7, 6 and 5 are all crammed into the Application layer in the TCP/IP model is that the folks that created the TCP/IP model believed that those responsibilities should be handled by the application itself, rather than within neatly laid out abstraction layers (thus helping to ease potential confusion that your question calls out).
