The concept of layers should not be confused with Burk's concept of levels of enterprise architecture. In the NIST model five layers were identified (business, information, application, data, infrastructure), and these were modified for the FEAF framework as four levels (business, data, application, technology). Both are related to Zachman's columns (all three images are from the FEAF where this is discussed). One could make a case that thiese layers relate to DODAF views as well. The concept of "layers" implies a flow from one to another, a precedence or order, as descrivet in NIST. Each of these layers consitiutes a different area or specialization in architecture and often a different member of the enterprise architecture team.
"If you do anything long enough, you eventually get good at it." MK
