Those on-net buildings

For a couple years now I have been keeping track of on-net buildings, but I have done so haphazardly.  With this forum in place, I think I will try to keep it more regulary and in a public format.  When I speak of an on-net building I mean that it has a fiber connection to someone other than the local ILEC.  Of course, different companies disclose this number differently, and some don’t give it at all, but we can get a general idea if we try:

Two numbers I suspect may not be comparable are the markets served of Zayo and Cogent, in that ‘markets served’ does not necessarily include a metro ring in all cases.  In the case of Zayo, since they focus on smaller cities, the definition of a ‘market served’ may be somewhat different in that a few small markets may be just one metro ring etc, and also the distinction between metro and regional fiber route miles is not made in the sources I have found (perhaps I shall find better ones).  In the case of Cogent, 35 markets is from an older link, but since then Cogent just gives its total markets irrespective of whether it has a metro ring in each.

Companies for which I have little information:

I know there are more smaller ones, but I don’t have them all at my fingertips all the time.  Rather, I intend to keep expanding and updating this list as I find the information.  So if you have some that I’m missing, let me know.  Likewise, if you have any updated information, or spot any obvious errors, please tell me.

In later posts, I will try to delve deeper into these numbers.