From: stephen@sprunk.org   
      
   On 07-Jul-14 20:11, Robert Heller wrote:   
   > Stephen Sprunk  wrote:   
   >> On 07-Jul-14 14:36, Robert Heller wrote:   
   >>> At this point it is not really a matter of whether to replace   
   >>> them or not, but what to replace them with: new copper or new   
   >>> fiber and what really makes more sense in the long term. Given   
   >>> that in time (10 years? 20 years? 30 years?) there will likely be   
   >>> need for more bandwidth than copper can ever handle, it makes   
   >>> little sense to put up *new* copper and then tear it down well   
   >>> before it wears out. We might as well future-proof ourselves and   
   >>> put up fiber. We may not need the bandwidth *now*, but in the   
   >>> future we will, and probably not in all that distant a future.   
   >>   
   >> OTOH, the labor and equipment to terminate fiber is more   
   >> expensive, which is why every other telco in the country is doing   
   >> FTTN.   
   >>   
   >> The last few hundred feet from the SLC to the home don't gain   
   >> anything from fiber; copper works just fine for such distances, and   
   >> already has 100+ times the capacity of what is needed today.  If   
   >> fiber is eventually needed for those runs in the far future, for   
   >> some reason, they're relatively easy to replace.   
   >   
   > The problem in most of Western Mass is that it is not a 'few hundred   
   > feet from the SLC', it is more like thousands of feet, or 2-3 miles   
   > in many cases, in which case the speed of the DSL is pretty poor. If   
   > by SLC you mean the concentrator.   
      
   SLC = Subscriber Line Concentrator   
      
   DSL does work over distances of several miles, but the speed drops as   
   the distance increases.  If you want "triple play" services, you need to   
   keep it under a mile or so--and below a certain population density, it   
   just isn't economically feasible to put enough SLCs out there.   
      
   > Note: most of the time there *isn't* a DSLAM, so all the concentrator   
   > handles is POTS. For anything other than POTS, the concentrator needs   
   > to have a DSLAM added. The equiment that exists at the node does not   
   > support anthing but POTS. Period. No Internet (other than dial-up)   
   > and no TV service.  *Phone* service is itself a non-issue. What is   
   > lacking is modern broadband Internet service.   
      
   DSL (or fiber) is just a different line card in the SLC.   
      
   A DSLAM actually resides at a CO somewhere, converting ATM traffic from   
   thousands of DSL (or fiber) line cards into IP packets; it has very   
   little to do with DSL per se.   
      
   S   
      
   --   
   Stephen Sprunk         "God does not play dice."  --Albert Einstein   
   CCIE #3723         "God is an inveterate gambler, and He throws the   
   K5SSS        dice at every possible opportunity." --Stephen Hawking   
      
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