I think you are referring, in the case of hierarchical synchronous
architectures (SONET/SDH), to the absolute periodicity of the timing
coming from clock sources. Frame slips and overwrites can occur when
too many ppm lagging or leading are exceeded, as I believe was implied
in your post. In contrast, I believe the notions that are being
discussed in this thread have more to do with the effects of
temperature coefficients of metallic conductors during shifts in
outside temperature conditions, and the ensuing changes in the nominal
velocity of propagation that accompany those changes, relative to the
speed of light.
In any case, I have been following this discussion from its beginning
with a great amount of interest, finding it a great memory jogger from
times misspent in my youth. I started a parallel discussion on my
forum, where today I responded to another poster with the following
observations, for anyone interested.
Maybe I'm way off.. Maybe its view of KISS but as engineers we should all be looking for the simplest answer. To me they key in Dragos' post was usage. All physics aside, the warm weather (seasonal) people go out more, use the internet less. In cold months, we stay in, use the net more. As for document any of us that run networks have seen this well document going back many years in our mrgt graphs. But then maybe he was refering to the physics, and I just try to simplify things to much.
Have. Good weekend all!