Besides the function blocks and reference points, the TMN functional architecture introduces some additional concepts. These concepts are:
According to recommendation M.3010, "TMN's Data Communication Function (DCF) will be used by the function blocks for exchanging information. The DCF provides layers 1 to 3 of the OSI RM".
The definition of the DCF concept has historical reasons: in initial drafts of TMN the DCF was modelled as a function block; it was therefore part of TMN's functional architecture. At present the DCF is no longer modelled as a function block; the text that describes the DCF remained, however.
Each of TMN's function blocks is itself composed of a number of functional components. The following functional components are defined:
These functional components can be divided into two categories:
Recommendation M.3010 contains a picture (Figure 12) to illustrate the relation between function blocks, functional components, the MCF and the DCF.