Hugh Pickens writes writes: "Daniel Berniger writes that one of the unexpected consequences of AT&T's transition to HD voice and all-IP networks is that the footprint of required network equipment will shrink by as much as 90 percent translating into a $100 billion windfall as the global telecom giant starts emptying buildings and selling off the resulting real estate surplus. Since IP connections utilize logical address assignments, a single fiber can support any almost arbitrary number of end user connections so half a rack of VoIP network equipment replaces a room full of Class 4 and Class 5 circuit switching equipment and equipment sheds replace the contents of entire buildings. AT&T's portfolio goes back more than 100 years even as commercial real estate appreciated five fold since the 1970's so growth of telephone service during the 20th century leaves the company with 250 million sq ft of floor space real estate in prime locations across America. "The scale of the real estate divestiture challenge may justify creating a separate business unit to deal with the all-IP network transition," writes Berniger who adds that ATT isn't the only one who will benefit. "The transition to all-IP networks allows carriers to sell-off a vast majority of the 100,000 or so central offices (PDF) currently occupying prime real estate around the globe.""