Vendors Race to Expedite DOCSIS 3.0, But Usefulness in U.S. Remains at Issue (September 2007)

Netherlands MSO Takes Plunge with Cost-Effective Use of Modular CMTS

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Vendors Race to Expedite DOCSIS 3.0
Vendors Race to Expedite DOCSIS 3.0

The cable industry took some important steps up the long climb to rollout of the full suite of DOCSIS 3.0 capabilities over the past month, but it remains to be seen how rapidly the new platform will be embraced in the U.S. even as overseas operators are pushing aggressively ahead. 

Where, during development of the latest Data Over Cable Service Interface Specification two years ago, industry leaders spoke enthusiastically of the power they would have to drive broadband to off-the-charts speeds for delivering high-value video content, today there’s a general uncertainty in domestic industry circles as to just how important DOCSIS 3.0 wideband is for the immediate future.

With operators fretting over ways to free up bandwidth to deliver more HDTV channels, the idea of allocating more channels to broadband for purposes of delivering video to PCs has lost a lot of its luster. And the idea of bringing over-the-top Web video to the TV via a souped-up DOCSIS channel has never gained much acceptance state-side. 

“You can sympathize with the bandwidth conundrum up to a point,” says one DOCSIS 3.0 vendor executive, speaking on background. “But you’ve got to wonder whether U.S. cable operators are missing a huge opportunity to outflank bandwidth-limited competitors by leveraging wideband in the broadband wars.” 

Indeed, given the surging popularity of Web media, user-generated content and social networking, the question of which should have the greater claim on bandwidth allocations, HDTV or broadband, is more pressing than the industry focus on freeing up more channels for HDTV would suggest. “The priorities could shift in a flash, and that’s why we’re making sure we’re ready with solutions that will endure as the certification process for DOCSIS 3.0 progresses,” says this vendor executive.

One recent effort in this direction saw Cisco Systems successfully complete interoperability tests at CableLabs to prove that its uBR10012 Cable Modem Termination System (CMTS) will accommodate not only downstream channel bonding in 2007 and 2008, but also upstream bonding later on. The tests paired the CMTS with Texas Instruments’ Puma 5 DOCSIS 3.0 CPE development platform, which will define 3.0-compatible silicon in future cable modems.

“The biggest significance of this milestone is that what all operators want is that 3.0 is on track and that the CMTS gear they are buying now is capable of supporting it,” says John Mattson, director of marketing, CMTS products, for Cisco.

CableLabs, in an initial ‘bronze’ DOCSIS 3.0 certification wave, will certify CMTS equipment as capable of combining channels to multiply downstream capacity only. However, in exchange for allowing tiered certification of that subset of the 3.0 standard in order to get product to market rapidly, the suppliers had promised operators that equipment eventually complying with the full ‘silver’ and ‘gold’ supersets of 3.0 features would not require forklift replacement of the first wave of CMTS and customer premises hardware.

“By delivering on upstream bonding, we’re keeping our word that we weren’t going to let the bronze tier delay the delivery of full 3.0,” Mattson says. “We believe getting downstream out the door need not be mutually exclusive from the full function set. Even though the [upstream and downstream 3.0] modems are a little further out, the fact that one of the silicon vendors is producing interoperable chips means operators can be assured the CMTS they’re buying won’t need a wholesale swap-out down the road.”

Mattson says Cisco soon will announce similar interoperability with Broadcom, another primary cable modem silicon.

“This successful demonstration of upstream channel bonding clearly shows there is significant momentum for DOCSIS 3.0,” says Tony Werner, Comcast Cable chief technology officer. “We believe this as an important milestone with DOCSIS 3.0 enabling a new generation of high-bandwidth services that will benefit businesses and consumers around the world.”

At the same time, two other hardware and software vendors, ARRIS and Incognito Software, advanced their plans to test for compliance with two other key elements of the full 3.0 specification: IPv6 addressing and DHCPv6 auto-configuration.

IP Version 6 affords a larger address pool and Dynamic Host Configuration Protocol enables assignment of dynamic or fixed addresses to devices on a network. IP management requirements for cable operators alone now exceed 100 million addresses, according to the companies.

Specifically, device provisioning and resource management software supplier Incognito announced that CMTS supplier ARRIS will be “a key participant” in the Incognito DOCSIS 3.0-IPv6 Interoperability Program, which enable CMTS and CPE to test the provisioning of their products in a multi-vendor, IPv6 environment.

“It is critical to the mutual success of operators and suppliers in the DOCSIS 3.0 open standards environment to establish and maintain these types of interoperability relationships,” says Jeff Brooks, senior director of business development for ARRIS.  “They not only ensure basic operation but have the potential to accelerate network transition and subscriber deployments.” 

In addition to ensuring forward compatibility of current equipment with the eventual full standard, Mattson says the interoperability efforts provide “another validation point along the road for high-volume, low-cost 3.0 modems. Do we expect to deploy 3.0 upstream in the next year? No. But we will deliver a CMTS that requires only a software upgrade, and along the way, we will start to turn on multicast, IPv6 and other features.” 

As U.S. operators sort out their bandwidth allocation strategies, European operators, who have far more bandwidth to play with owing to more limited TV options and less aggressive adoption of HDTV by consumers, are moving past the initial trial stage to make use of DOCSIS 3.0 capabilities, including what is known as Modular CMTS in conjunction with introducing 100 mbps service.

Indeed, many believe the economics are now in place for widespread 100-mbps cable broadband, as evidenced by Multikable’s move in the Netherlands to deploy the BigBand Networks wideband and M-CMTS solution to cost effectively increase broadband speeds by as much as 75 percent across its service territories. BigBand believes this is the first commercial deployment of M-CMTS based on the CableLabs specification. The deployment has covered 50,000 subscribers so far and is adding more weekly.

Critically, Multikable says, the M-CMTS solves the cost equation for implementing CableLabs’ DOCSIS 3.0 channel bonding, which enables 100-megabit-per-second and faster downstream data speeds over multiple 6-megahertz cable RF channels. “BigBand’s solution has allowed us to roll out high-speed Internet services at a significantly lower cost than would’ve been incurred by a rollout with integrated CMTS from other vendors,” says Stefan van Dijk, manager at Multikabel. “Without M-CMTS we simply didn’t see how expanding bandwidth would be economically viable.”

While DOCSIS 3.0 provides a method for expanding bandwidth, “it doesn’t tell you how to do it economically,” says John Holobinko, vice president and general manager, cable IP, for BigBand. “There’s nothing about 3.0 that is a breakthrough on the cost side. If you bond three channels and your costs are three times larger, you can’t do this.”

The economic answer, he says, “is M-CMTS, which provides the most disruptive cost factor since DOCSIS itself.” 

According to Holobinko, the economics of the M-CMTS rest on a new architecture that places processors on each CMTS line card and leverages a high volume supply of quadrature amplitude modulators (QAMs) in the field. Both modem termination cards and QAM components can be added incrementally, where and when demand justifies, rather than integrated on each CMTS line card at manufacture. The QAM modulators decoupled from the CMTS chassis can be produced in greater volume, and so lower costs. BigBand shipped more than 70,000 edge QAMs in 2006.

Whereas the central bus architecture of last-generation integrated CMTS reduced data throughput with the addition of channels, the mesh architecture of the M-CMTS yields more capacity with each added channel and at lower cost.

“Basically you’ve taken the proven technology of the CMTS and the cost benefits of high volume edge QAM production and used processing power to add channels very gracefully and economically,” Holobinko says. “If you want to expand density without reprogramming service groups or taking cards out, you just add channels as you need them.”

The upshot, he says, is that operators can offer new 100-mbps services today on DOCSIS 3.0 channel bonding modems without waiting for new cards or new software.

Multikable’s headstart on M-CMTS stems from an early access program (EAP) initiated by BigBand Networks last December to provide the platform to multiple operators in Europe, Asia and the U.S., including Multikable and Austria’s LiWest Kabelmedien GmbH. Since then, those operators have been working with BigBand’s M-CMTS system, comprising Cuda12000 CMTS and BEQ6000 QAM RF digital transmission equipment.

The EAP was specifically designed to accelerate implementation of the DOCSIS 3.0 specification worldwide by allowing cable operators to gain hands-on experience with downstream channel bonding and to prepare requisite operations and billing support systems.

“One of the key things we’ve heard from Multikabel is that Cuda has the ability to support their VoIP as well as high-speed data. It’s stable and real and ready to roll out in large numbers,” Holobinko says. “We have commercial deployments in Japan, and we are involved with a number of other operators who have purchased the M-CMTS for multiple bonded channels in the Asia Pacific Rim region and contracts signed with operators in U.S.”

Unlike proprietary wideband channel bonding techniques meant to operate only with specific modems from a single vendor, BigBand says the Cuda supports both DOCSIS 3.0 downstream channel bonding modems and DOCSIS 1.0, 1.1 and 2.0 modems on the same channels, and can increase bandwidth delivered over the widely-available DOCSIS 2.0, 1.1 and 1.0 modems to 25 mbps or more.

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