Too much of the whole of internetworking is still left to the student to synthesize in the University of Hard Knocks. We're still providing isolated bits and pieces without a larger structure to hang them all together. The shortcoming isn't the academician's fault, save that we are thrust into a discipline that hasn't grown up yet. The following taxonomy is intended to help us through an adolescence. Various textbooks, industry literature, and short courses cover parts of this taxonomy.
None cover all.
A distressingly large percentage seem to skip from parts of the plumbing to the business case issues and missing both the technology of internetworking and the people issues represented by NIC, NOC and applications support. Many textbooks and academic curricula also attempt to cover all of the plumbing, working up the ISO Reference Model from the bottom. The tacit assumption is that one must be competent at everything to be good at any part of networking - true a decade ago, but no longer. This inevitably leads to short shrift of the technical people and management issues that fall in the application layer - always in the cleanup section in the back of the book. I'm sketching this taxonomy firstly to identify the shortcomings in various texts and their consequent curricula.