I'll add onto what you said: if you're afraid of RFCs, look for a Wikipedia page of that topic. They're generally much more readable and have diagrams. For exa

I'll add onto what you said: if you're afraid of RFCs, look for a Wikipedia page of that topic. They're generally much more readable and have diagrams. For example, trying to learn the TCP fields from the RFCs alone is hard because of how many there are. Starting with the Wikipedia page on TCP and then following the linked RFCs is easier.