I actually found the OSI Reference Model to be incredibly helpful both as a student and later in my work life as an operations engineer. I was able to successf

I actually found the OSI Reference Model to be incredibly helpful both as a student and later in my work life as an operations engineer. I was able to successfully break problems down in a methodical layer-by-layer approach to troubleshooting and find the root causes and solve extremely esoteric and difficult problems that other people, including very smart talented engineers, were completely stumped by. This wasn't because I was smarter or knew some secret, but because breaking problems down into smaller pieces and identifying and learning tooling to examine those problems in isolated pieces makes it easier to find the actual cause. While it is very true that the OSI Reference Model doesn't map to real life systems exactly, it's still a relatively accurate view with a little bit of hedging as to what layers something might fit into. Additionally many of the protocols that were built for OSI networks have been adapted and implemented on top of TCP/IP networks and are extremely valuable in some circumstances at global scale, because the telecoms people designing these systems /thought about/ global scale from the get-go, where-as it was mostly an afterthought for later computer systems researchers. X.500 in particular is a fantastic protocol, that while convoluted and esoteric, enables some very complex replication topologies while providing strong guarantees that are simply not possible in lighter weight protocols. When thinking deeply about identity management and authentication, X.500 is not a bad thing to fully understand, even if you end up implementing a lighter weight protocol, because while "over-engineered" it's well thought out. That said, ASN.1 notation is a hellacious curse and should have been burned and buried in the pit it came from before it ever saw the light of day. Unfortunately, it's a key component of nearly all the X. series standards built on top of OSI.