FastNet Futures included a session on VDSL2. VDSL was supposed to be "very-high-speed" DSL, but ADSL2+, the most-recent ADSL standard issued more than a year ago, is already faster than some versions of VDSL. Now many companies are working to develop technologies and establish standards for the next generation of "ultra-high-speed" DSL.
In the FastNet session, we heard a presentation by Behvooz Resvani, CTO of Ikanos Communications, on the work Ikanos is doing to extend VDSL with the goal of providing symmetric 100 Mbps service. We were intrigued enough to arrange to visit Ikanos and meet with Piyush Sevalia, Director of Product Marketing.
Ikanos specializes in developing "silicon solutions that are focused on delivering fiber-fast broadband access over existing copper wiring" -- that is, the chips to power very-high-speed DSL. Other companies use Ikanos chips to produce DSL products sold to service providers and end users. Piyush told us that Ikanos has to date "shipped over 2 million ports capable of 50 Mbps or more" -- enough chips to provision one million high-speed DSL lines.
In Japan, both NTT and KDDI are deploying VDSL based on Ikanos chips integrated in products supplied by Sumitomo Electric and NEC. In Korea, KT and Hanaro Telecom are deploying Ikanos-based VDSL products from Samsung and others.
Piyush told us that today's VDSL deployments are based on the Ikanos Fx 7030 chip, designed for 70 Mbps downstream and 30 Mbps upstream. The next generation of products will be based on the latest Fx 10050 chip, with 100 Mbps down and 50 Mbps up (or symmetric 50 Mbps). The "trick" for getting these high speeds is to extend the upper end of the frequency range used by VDSL, currently limited to 12 MHz. Ikanos' Fx chips operate up to 17.6 MHz to gain higher speeds. This is currently non-standard; regulators in Japan and Korea are allowing operation at higher frequencies to enable super-high-speed DSL operation. The final step will be to further extend the frequency band to reach 100 Mbps symmetric.
We asked about the reach of products based on Ikanos chips. Piyush said the highest speeds are based on short subscriber loops, typically 1000 feet in Japan and 2000 feet in Korea. At 1 kilometer (about 3300 feet), speeds would be 50 Mbps downstream and 7 to 10 Mbps upstream; at 2 km, speeds would be 30 Mbps down and 3-4 up. Piyush said that 80% of subscriber loops fed from digital loop carrier (DLC) terminals are 2 kilometers or less.
With these new technologies, telephone companies will have several ways to obtain much higher speeds. One would be to deploy fiber all the way to the home (FTH). The other would be to extend fiber to within 1 or 2 kilometers of homes in those areas where they don't already have DLC cabinets, and then use advanced VDSL technologies such as those from Ikanos to reach the last kilometer or two.
( www.ikanos.com )