On Wednesday 26 August 2009 23:16:17 Robert Enger - NANOG wrote:
As tedious as the downstream can be, engineering the upstream path of a cable plant is worse. A lot of older systems were never designed for upstream service. Even if the amps are retrofitted, the plant is just not tight enough. Desirably, fiber should be pushed deeper; the quantity of cascaded amps reduced, coax fittings and splitters replaced and so on.
On 8/26/2009 10:25 AM, Richard Bennett wrote:
The trouble with broadband in rural America is the twisted pair loop lengths that average around 20,000 feet. To use VDSL, the loop length needs to down around 3000, so they're stuck with ADSL unless the ILEC wants to install a lot of repeaters. And VDSL is the enabler of triple play over twisted pair.
An interesting question: as the population gets sparser, the average trench mileage per subscriber increases. At some point this renders fibre deployment uneconomic. Now, this point can change: 1) as we deploy fibre we'll get more efficient at it - I think VZ's cost per sub has come down quite a lot since they started the FIOS rollout. 2) the flip side of the cost to serve a subscriber is of course revenue, and if you can find other services to sell'em you can go further. may also be scope for tiered pricing 3) public sector investment Going the other way, as the population gets denser, it becomes harder to provide an acceptable broadband wireless service because of spectrum limitations. You either need more and more cells (=more and more sites and more and more backhaul), or more and more spectrum. Where's the crossover point? There are clearly places where some fibre investment (like L(3)'s proposed deployment of many more POPs) would make it possible to get good service out using radio from the end of the fibre, precisely because they are sparse. There are clearly places where fibre to the home will eventually arrive. Is there a broadband gap between the two groups, however, where it's not dense enough to ever deploy fibre and too dense to deploy good wireless? Or can we rely on FTTH for one lot and RTTR (Radio to the Ranch) for the other?