CableLabs completes first round of Docsis certification

CableLabs completes first round of Docsis certification
LOUISVILLE, Colo. — CableLabs and the Cable Broadband Forum have completed the first round of certification for Docsis (Data Over Cable Service Interface Specification) two-way cable modems, they said yesterday (March 4). While the process of ascertaining interoperability has taken longer than cable-modem advocates hoped, the rapid proliferation of first-generation one-way cable modems in the market has spurred hopes among Forum members that cable TV multi-system operators may have an unstoppable lead over phone companies in providing residential broadband options.

Indeed, the high spirits evident at Thursday's announcement stood in marked contrast to the exasperation expressed in Washington at the ADSL Forum meeting, attended by equipment suppliers and phone carriers promoting asymmetric digital subscriber line. Still, only modems from Thomson Consumer Electronics and Toshiba America Information Systems Inc. were certified for retail sales this week, leaving many manufacturers such as Com21, Nortel, 3Com, General Instrument, Terayon and Motorola in limbo. CableLabs president Richard Green said that additional certifications will be announced "no earlier than the end of April," based on a second wave of tests that are set to begin March 15.

Rouzbeh Yassini, executive consultant to CableLabs, said that the three-year test program may have seemed long, but is probably a record in the communications industry. It involved more than 50 test parameters for subscriber modems, testing their access with four vendors' head-end equipment, or Cable Modem Termination Systems (CMTS). Yassini stressed that there is a separate qualification program for the CMTS equipment itself, which is to be completed later this year. David Fellows, chairman of the certification review board at CableLabs, hinted that software-download features were a key area where some cable modems had difficulty meeting the spec.

Even as modems meeting the Docsis Media-Access Control release 1.0 are certified, CableLabs is readying the draft for 1.1 at the end of March. This upgrade will add packet-prioritization for the MAC, to allow better support for Voice over Internet Protocol and other features. While some developers are worried that 1.1 also could face a multi-year certification process, Fellows said that 1.0 deals with "90 percent of the functionality of the MAC, including modulation, demodulation, and encryption. The 1.1 release represents relatively minor software additions to the MAC layer."

Green added that "the first wave of testing is always the most difficult, and was developed to reduce consumer risk. We will hope that additional waves of testing will be conducted quicker."

The next step involves an advanced physical layer which Broadcom Corp. and Terayon are working on. This will be presented to an IEEE 802.14 meeting beginning Monday (March 8), with a draft then passed to CableLabs, where it may become Docsis 1.2, though Fellows emphasized that the IEEE/CableLabs collaborative process is still in its infancy.