CableLabs has selected “packet bonding” over a rival technique for the emerging DOCSIS 3.0 specification and modular-cable modem termination system (M-CMTS) architecture.
News of the packet bonding selection first appeared last week in Cable Digital News. A CableLabs official confirmed that a selection had been made, but declined to be more specific. A range of sources familiar with the situation confirmed that the cable industry’s Louisville, Colo.-based R&D house selected packet bonding over a competing proposal called “MPEG bonding.”
Although DOCSIS 3.0 and the M-CMTS project are somewhat independent, they do work together on the facet of channel bonding, a technique that will enable cable operators to offer speeds of 100 Mbps and greater, and therefore, provide a competitive foil to new fiber-to-the-premise (FTTP) technologies. The modular CMTS architecture enables the CMTS to share edge QAM resources for video-on-demand and DOCSIS-based data applications.
Channel bonding “is a lynchpin of both pieces – DOCSIS 3.0 and the modular CMTS,” said CableLabs Chief Technology Officer Ralph Brown. “The important thing is that the decision was made, and it was a significant one. The [DOCSIS 3.0] project is moving ahead at a rapid pace.”
Vendors such as Motorola Inc. and ARRIS have been championing the packet bonding technique, while Cisco Systems and silicon startup BroadLogic have been seen in the MPEG bonding camp. CED offered an in-depth technical primer on the subject in the April issue.
The decision to go with packet bonding does not impact the product plans of BroadLogic, according to company President & CEO Tony Francesca. BroadLogic is building a wideband receiver chip for customer premise devices (CPEs), not CMTSs that reside on the cable network.
“We anticipated that there would be many flavors of channel bonding…and we made sure that our implementation is adaptable and compliant to those moving forward,” Francesca said. “We’ve implanted a specific implementation that gets to that objective [DOCSIS 3.0] while being indifferent to the channel bonding part of it. When it comes to time-to-market and cost, we think we have the lowest cost and best performance [product]. Channel bonding is just one piece of it.”
Many believe the decision was based partly on the fact that packet bonding gives operators a faster time-to-market because the technique can be deployed with existing technologies. Legacy CMTSs, for example, can support packet bonding with a software revision. Modem vendors can also support multiple channels, though they have to combine cards and silicon, which adds costs. Down the road, modem vendors will have the financial benefit of using a new class of cable modem silicon that condenses the function on a smaller (and cheaper) form factor.
“MPEG bonding requires software changes at the CMTS and the cable modem, but packet bonding can be implemented in software-only at the CMTS. It is potentially implementable at the cable modem with multiple cable modem chips,” explained Mike Patrick, a data-networking architect at Motorola.
Although DOCSIS 3.0 will help North American cable operators compete with new fiber-fed services, the technology behind it is needed first in Asia and Europe, where cable is under fierce speed and pricing competition with DSL and fiber-based service providers.
“Eventually the requirement will be strong for deployment purposes in the U.S…but the burning desire to have products on the street is outside the U.S. right now,” Francesca said.
ARRIS has pre-standard and pre-general availability channel bonding products in the field today. “It’s not like we’re mass-producing it in the factor yet, but the bottom line is that it is usable by real customers. We’ll have product coming out based on channel bonding by the fourth quarter,” said Tom Cloonan, chief technology officer of ARRIS’ broadband division, which first demonstrated its “FlexPath” technology at the 2004 National Show, and again at last month’s show in San Francisco. On the modem front, ARRIS initially will introduce a four-channel cable modem, though it plans to offer models that bond together even more channels.
Other vendors will most certainly follow suit with new classes of modems that support channel bonding, and probably not a moment too soon.
“We have outgrown the 10-year-old single channel cable modem. It’s obsolete,” said Jeff Huppertz, BroadLogic’s vice president of marketing and business development.
