  In this paper, we argue that the energy analyst's understanding of the metro
area network must be supported by a standard that (a) generalizes diversity,
through the means of the abstraction of the implementational model, while (b)
distinguishing between deployments through physical reference points. The need
for this kind of model has already been foreseen in the ITU-T's Recommendation
Y.110, including the need "to illustrate how system performance can be affected
by implementation." Preliminary results that concern the access network are
presented.
