Alcatel-Lucent intros VDSL2 bonding, sleeping modems

by Ed Gubbins

Alcatel-Lucent today announced two new innovations in its DSL product line to be available in next year’s first quarter, including support for VDSL2 bonding and modems that power down when not in use to save energy, green modems.

Release 4.0 of the vendor’s Intelligent Services Access Manager platform includes support for bonding VDSL2 lines, a technique it says could double bandwidth speeds for some customers, depending on their proximity, potentially allowing 50-megabit-per-second downstream speeds.

Alcatel-Lucent’s biggest VDSL2 customer, AT&T, has talked about the promise of line bonding for some time while repeatedly pushing back its timetable for deploying the technology. And though the carrier initially talked about the bandwidth-boosting powers of line-bonding, it has more recently emphasized its potential to extend broadband over longer distances instead.

For example, AT&T has talked about offering 37 Mb/s over distances of 3,000 feet. And this month a Telephony reader and AT&T customer reported being told by a sales rep that the carrier was doing VDSL2 bonding today for distances up to 3200 feet.

“Pair bonding isn't necessary for all customers, nor are things like two [high-definition video] streams or faster Internet tiers dependent on pair bonding,” an AT&T spokesperson said last December. “Rather, we'll use pair bonding where needed as a way to expand our U-verse service area to customers at longer loop lengths. It will allow us to reach a broader customer base.”

Alcatel-Lucent said its line cards could be used to deliver 20 Mb/s up to 1400 meters (or nearly 4600 feet).
In an interview last year, Pieter Poll, chief technology officer for Qwest Communications, which is trialing VDSL2 gear now, called 2009 “probably the right time frame” to deploy bonded lines. Alcatel-Lucent said it is shipping its gear to select customers now and more generally in next year’s first quarter.

By several accounts, the main gating factor on the deployment of VDSL2 bonding is the availability of customer premises equipment (CPE) that supports it. In fact, Alcatel-Lucent said its gear has supported VDSL2 bonding for several months and that it is now testing the first CPE for the North American market – starting with two modems in its own CellPipe portfolio.

Some have attributed the lack of CPE support to a lack of demand for VDSL2 bonding in the market. When asked this month why Zhone Technologies doesn’t sell bonded VDSL2 gear, Steven Glapa, the vendor’s vice president of marketing and product management, said, “We haven’t seen anyone looking for it.”

The technology is limited by a few factors, including the simple requirement for extra pairs of existing copper. Thus far, most residential DSL bonding has involved ADSL2+. For example, last fall, SureWest Communications launched 10-Mb/s and 6-Mb/s broadband services over a bonded ADSL2+ network in its incumbent territory.

In addition to VDSL2 bonding, Alcatel-Lucent also announced a new ADSL modem that switches into low-power mode when not in use. When traffic levels drop, the modem automatically lowers its bit rate and cuts its power consumption by 25%. The technique is based on industry standards but hasn’t been widely employed, the vendor said, because re-activating the modems from low-power mode can cause power fluctuations, leading to crosstalk and destabilizing the network. Alcatel-Lucent is offering the products now because it has overcome those issues, the company said.