DSL Prime: VDSL's Phantom Menace

While the VDSL industry continues its constant infighting over the future, business moves forward making DSL decisions today that may make these wars irrelevant.

by Dave Burstein DSL Prime [May 22, 2003]

VDSL Olympics climax
Anaheim June 18-19 could decide
Testing is going on right now at Telcordia and British Telecom labs, as much of the industry waits for a clear winner. If the telcos involved take a position, T1E1.4's June meeting may vote; otherwise, they hope to reach a conclusion in the following month or two. Other standards bodies, including ITU and FSAN, are watching closely and often have the same membership. The general assumption is they will rapidly ratify whatever T1E1.4 decides, but a group of telcos at the ITU (SG15/Q4) in Durango suggested approving dual line codes. Many telcos around the world will be strongly influenced by T1E1.4, making its decision worth hundreds of millions in equipment sales.

The arguments
DSL Prime readers have heard from both points of view. DMT claims better compatibility with existing DMT ADSL, can serve either ADSL or VDSL from the same chip, and promises exciting binder level performance improvements demonstrated with DSM. QAM is far ahead in the market, proven for two years and shipping in the millions. It works well, and is reasonably space and power efficient.

Most of the industry, including the telcos making the final decision, is prepared to move forward with either line code, and wish (as I do) that the debate soon ends. But for those involved, the stakes are very high and information critical. I therefore invite all the partisans to suggest articles for DSL Prime's web site. They will be posted on the web, and briefly summarized in the e-mail. For this, I welcome strong opinions (under your byline, not mine), and will attempt to publish all received by June 1 before June 6. My guess is the readership of the pieces will be modest, but may include some of the key people you're looking to reach.

The next step
"What happens if the lab tests are basically tied?" a chip designer asked me. That's precisely what she and other informed engineers expect, so it's unlikely to decide a winner on purely technical grounds. Both sets of chips are likely to perform well but not perfectly, with advantages in different areas. A large group of very powerful vendors supports DMT (Alcatel, TI, Globespan, Broadcom, etc.) giving it a strong front in the politics. If Alcatel and TI had delivered the chips promised almost two years ago, DMT would be hard to oppose. But now the track record of Infineon's and Metalink's QAM chips means a great deal to the always conservative telcos, so there's no certainty in this one.

Some huge contracts in Korea and Japan may well be decided before the standards, and if carriers there choose either line code it will be enough of a market for chip vendors to continue the product line.QAM chips can easily be repositioned as "Tomorrow's LAN," extending 10 Mbps and higher Ethernet for building and campus deployments. DMT could move forward as ADSL3+. Carriers like SBC, BT, Bell Canada, and FT will be crucial in determining where the western market will go. They are the key votes in the standards committees, and likely to follow the decision.

Copyright 2003 Dave Burstein.
The DSL Prime Newsletter is reprinted with permission.

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