SHDSL was supposed to supplant SDSL as of 2003 (or so) I thought, but I never see advertised speeds go beyond a 1.5 Mbps SDSL line... SHDSL goes to 2.3 Mbps and has other advantages over SDSL (longer loop lengths for given speeds, less interference with other data lines, 4-wire mode). I'm not that well educated on the topic, but I also had the impression there could be some cost savings.
Today T1's are often delivered using this technology, but why not offer SHDSL from the customer to DSLAM like a normal dedicated DSL line.... and give customers the speed they want, distance depending???
Are ISPs just not ready to upgrade their DSLAM equipment, or don't want to cannibalize their higher priced bonded T1 services?
You may not need the SLA of a real T1, but you'd sure love 2.3 Mbps up and down for let's say $150/mo or so.
First.... you have to look at who is selling SDSL. Basically Covad and a few small CLECs. They bought non-standards-based SDSL long ago and they are still using the equipment.
Given the financial state of Covad I can see why they aren't going around ripping out all their DSLAMs.
There may be some hope though, with the new Earthlink money they are upgrading DSLAMs to support LPV and ADSL2 in larger markets. I *think* that the new DSLAMs will also be offering new SDSL speeds as well, which probably means SHDSL (and finally the ability to hook a real router up to an SDSL line).
Most DS-1s today are delivered using either HDSL or HDSL2 on 1 or 2 pairs.
Your ILECs aren't going to upgrade equipment necessarily because of the availability of a different technology. Even with existing technology many consumers and businesses are in a fight just to be able to get ADSL services.
Covad, XO, etc. that are selling SDSL services already may not upgrade given their investment in existing equipment.... and given the state of competition now for internet services.
With the price of service dropping to $12.99/mo and the uptake of those discounted services increasing, I wouldn't want to be one of the other players and be making large capital expenditures for upgrades right now. I'd be worried about staying in business. People are price driven.....
Just my opinion though, take it for what it's worth.
Michael is the owner of FreedomFire Communications....including DS3-Bandwidth.com and Business-VoIP-Solution.com. Michael also authors Broadband Nation where you're always welcome to drop in and catch up on the latest BroadBand news, tips, insights, and ramblings for the masses.
http://ezinearticles.com/?SHDSL----Why-Hasnt-It-Replaced-SDSL?&id=627956
