I almost finished the ccna, in the meantime I'm following Pentesting courses, I noticed enough interesting protocols at the session level. I wish I could understand them as I did with cisco, but I found only generic materials. I wish I had something deeper, which could also include levels 6 and 7. Where can I find what I'm looking for?
The OSI model is a theoretical model, and there aren't any protocols in use today that follow it. So layers 5-7 are just "concepts." In the TCP/IP model (closer to what is actually in use today), there are no session and presentation layers. Everything is simply "application." This question and answer may help you.