Technically, any of the architectures espoused by some of the commentators on this thread will work, and would at least be an order of magnitude better than what is available in the local loop today. One of the commentators, however, did underscore the biggest challenge by far to national broadband. (Even the watered down version consisting of a welter of autonomous municipal networks as is the subject of this thread). And that challenge is the stranglehold that incumbent telcos have on the local loop, and their caustic, anti-progress influence in City Halls, Sate Legislatures, and Washington DC. That is why the Australian NBN serves as a good example of how to wrest control of the local loop plant away from the telcos. In many areas of the US a parallel fiber network is already in place, built out by the Federal School Lunch e-rate program. Here, regrettably, the telcos have exerted their caustic influence by compelling legislators to allow only school and library traffic on the e-rate fiber. As far as a purely technical solution, in my own experience some years ago I worked in the entertainment business in the Burbank/Glendale, Ca. area. Both cites, led by the visionary Burbank Department of Water and Power, built out dark fiber networks. Of course, getting municipal fiber in Glendale required an intense struggle with the incumbent telco, which sent a representative to every city council meeting arguing that municipal fiber was bad for the city residents. David On Sat, Feb 2, 2013 at 6:35 PM, Leo Bicknell <bicknell@ufp.org> wrote:
In a message written on Sat, Feb 02, 2013 at 09:28:06PM -0500, Scott Helms wrote:
I'm not saying that you have to, but that's the most efficient and resilient (both of those are important right?) way of arranging the gear. The exact loop length from the shelves to the end users is up to you and in certain circumstances (generally really compact areas) you can simply home run everyone. Most muni networks don't look that way though because while town centers are generally compact where people (especially the better subdivisions) live is away from the center of town in the US. I can't give you a lot insight on your specific area since I don't know it, but those are the general rules.
If the goal is the minimize the capital outlay of a greenfield build, your model can be more efficient, depending on the geography covered. Basically you're assuming that the active electronics to make a ring are cheaper than building high count fiber back to a central point. There are geographies where that is both true, and not true. I'll give you the benefit of the doubt that you're model is cheaper for a majority of builds.
On the other hand, I am not nearly as interested in minimizing the up front capital cost. It's an issue, sure, but I care much more about the total lifecycle cost. I'd rather spend 20% more up front to end up with 20-80% lower costs over 50 years. My argument is not that high count fiber back to a central location is cheaper in absolute, up front dollars, but that it's at worst a minimal amount more and will have neglegable additonal cost over a 40-80 year service life.
By contrast, the ring topology you suggest may be slightly less expensive up front, but will require the active parts that make up the ring to be swapped out every 7-20 years. I believe that will lead to greater lifecycle cost; and almost importantly impeed development of new services as the existing gear ends up incompatable with newer technologies.
-- Leo Bicknell - bicknell@ufp.org - CCIE 3440 PGP keys at http://www.ufp.org/~bicknell/