Cisco Systems and Texas Instruments claimed they successfully tested the interoperability of their equipment, based on CableLabs’ Data Over Cable Service Interface Specification 3.0, bonding two upstream channels—the first time such upstream-bonding features have been verified as interoperable, according to the duo.
The testing took place at a CableLabs interoperability event for DOCSIS 3.0 (a.k.a. “wideband”) equipment vendors the second week in July.
“It’s a milestone that shows we’re moving down the path to full DOCSIS 3.0,” said John Mattson, Cisco’s director of marketing for cable modem termination system products.
The hallmark feature of DOCSIS 3.0 is channel bonding, which combines multiple quadrature amplitude modulation (QAM) channels to achieve higher bandwidth. Initially, cable operators--led by Comcast -- have shown more interest in the downstream-bonding capabilities, as downloads typically consume more bandwidth in broadband networks today than uploads.
CableLabs, to speed up getting certified CMTS gear with downstream-bonding features into the market, set up a tiered certification process to begin in October. The initial “bronze” DOCSIS 3.0 certification will cover only downstream-channel bonding, with upstream set for a later “silver” designation before getting to full support for the entire specification.
Also worth noting that there’s still plenty of upstream runway left in DOSCIS 2.0—that earlier spec allows for up to 20 megabits per second.
That said, Mattson predicted cable operators will eventually have a need for upstream-bonding features. “At some point MSOs will want to go more than that, especially for commercial services,” he said. “If they’re offering 50 megs down they will want to offer 50 megs up.”
The July test paired Cisco’s uBR10012 CMTS with TI’s Puma 5 DOCSIS 3.0 reference-design modem, bonding two upstream QAM channels. Mattson said he didn’t know what the upstream bandwidth achieved in the demo was.
