By and large I personally think that most of us are much more comfortable with layer three than any other layer in the OSI model. We deal with it each and every day. We have a number of tools at our disposal which make it very easy for us to see if/when it’s working and just how the data is traveling. To start with though, we have to know just how things are supposed to work.
When I entered the Army in July 1999, I came in as 31F (switch operator). Anyone who worked with MSE will remember that it had almost absolutely no data capabilities, but also that it was extremely easy to troubleshoot. Signal flow for MSE was pretty darn easy to understand. If you understood the idea of how the system worked, the signal flow was easy to follow. With the introduction of JNN and IP data networks to tactical communications, logical and physical said “It’s been fun” and headed their separate ways leaving our operators and even ourselves busy scratching our heads wondering how the hell it all worked.