Cable IPTV Debate Brews
Cable operators across the globe may be eager to introduce IPTV services, but how they deliver them -- directly through the cable modem termination system (CMTS) or via a CMTS "bypass" scheme -- is rapidly becoming a point of contention.
BigBand Networks Inc. (Nasdaq: BBND) is one of the vendors advocating a CMTS bypass approach with "vIP PASS," a platform that feeds video through the edge QAMs. BigBand holds that the approach is inexpensive when compared to piping video through the core CMTS. Furthermore, BigBand, which gave up on core CMTSs in the fall of 2007, argues that CMTSs are also prone to dropping packets, which is a big no-no for video. (See BigBand Lays Cable IPTV Groundwork and BigBand Terminates CMTS.)
Although Arris Group Inc. (Nasdaq: ARRS) counters most of BigBand's claims (more on that later), other vendors have developed or are pursuing CMTS IPTV bypass products of their own.
Motorola Inc. (NYSE: MOT), for example, unveiled the Docsis IPTV Bypass Architecture (DIBA) in 2006, basing it on proprietary protocols. The company, which makes core CMTS products, originally viewed DIBA as an opportunity to sell massive amounts of downstreams using its own edge QAMs, if and when cable IPTV took off.
Motorola still thinks bypassing IPTV traffic to the edge QAM could save MSOs plenty of capital, and the company is working on a DIBA demo that simulcasts about 100 traditional broadcast channels over IP.
A DIBA deployment for unicast video still hasn't happened, though. "We have nothing in the field because most of our customers are not at the point of…considering something like this," says Mike Cookish, director of product management for Motorola's CMTS business unit.
That's not the attitude at Harmonic Inc. (Nasdaq: HLIT), whose video-over-Docsis demo got high marks at a CableLabs meetup in 2007. (See Harmonic's Bright Idea .)
"We are beyond the proof of concept" for CMTS IPTV bypass, Gil Katz, senior director of cable solutions for Harmonic, told Cable Digital News recently at the vendor's headquarters in Sunnyvale, Calif. He says one cable MSO customer in Asia is already doing this today using Harmonic's NSG9000 edge QAM. "All major operators... one way or the other are looking into IPTV."
BigBand, meanwhile, has not yet revealed its first vIP PASS deployment partner, but it's believed to be an MSO based in Korea.
Not all the CMTS IPTV bypass activity is happening outside the United States. H&B Communications is deploying IPTV services using a CMTS bypass system outfitted with GoBackTV Inc. edge QAMs and SecureMedia Inc. 's conditional access/digital rights management technology.
The CMTSs' side
Although Arris sees some potential for CMTS bypass, it thinks core CMTSs (or more specifically, its CMTSs) are perfectly capable of supporting IPTV services at an acceptable price.
Tom Cloonan, Arris's chief strategy officer, says CMTS memory buffers today are plenty deep enough today to handle the load and keep packets from dropping off.
"Typically, today's CMTS would have much larger buffers than edge QAMs," he says, noting that CMTSs are also better equipped than edge QAMs to handle big bursts of traffic.
He says CMTSs can likewise be tuned to handle IPTV traffic by dropping some Docsis features, a move that should enable the box to boost the number of downstream channels it can process at one time.
Although it would behoove Arris to protect its CMTS business, it also makes edge QAMs. "We can thrive with either decision... but we see limitations on the MSOs if they choose the bypass approach," Cloonan says.
He also bristles at the notion that CMTS IPTV bypass is cheaper, because it's not necessarily fair to compare the two.
"The CMTS has to manage the upstream. That's the most challenging job," Cloonan says. "IPTV [services] need to select channels... through the upstream, but they [the edge QAM vendors] don't include that in their price comparison. It's kind of an apple and elephant comparison." He also thinks that core CMTS downstream port pricing will eventually close the gap with those for edge QAM downstream ports.
Arris isn't a lone voice in the forest.
Guangzhou Digital Media Group of China offers one the best cable examples so far. It's rolling out IPTV services to all of its 2.5 million cable subscribers within the next five years using Microsoft Corp. (Nasdaq: MSFT) Mediaroom and set-tops from Tatung Co. Rather than bypassing the CMTS, Guangzhou Digital is delivering video directly through the Casa Systems Inc. C3200, a Docsis 3.0-qualified CMTS. (See Chinese MSO Does IPTV With Microsoft.)
Guangzhou represents Microsoft's first cable deployment for Mediaroom, and more are coming, according to Ben Huang, Microsoft Mediaroom's director of product management. Just don't expect any of them to show up in North America. Asia and Latin America "are the frontrunners" when it comes to Microsoft's cable-related IPTV activity, he says.
That's not a huge surprise, since operators in those regions may not have the QAM-based digital legacy that MSOs in North America have today. "We still believe there is an opportunity in North American cable, but those are further out in time than the other regions," Huang says.
If domestic cable MSOs do pursue CMTS bypass architectures for IPTV in a big way, some industry insiders wonder if the industry should draft some standards so MSOs don't get locked into particular vendors' product lines.
BigBand's bypass architecture, for example, requires a small software client in the modem that communicates back to the vendor's vIP PASS server. But the company is trying to show its architecture can still play nice with the industry.
For example, VP of marketing John Holobinko says vIP PASS uses Docsis mechanisms and can "work with any CMTS, because we're using pass-through messages like any other IP messages." The first vIP PASS deployment is running on "one of the two largest suppliers of CMTSs," which could mean gear from Arris, Cisco, or Motorola. He also confirmed that a recent demo conducted at the CableLabs Winter Conference in Colorado Springs was done with the Cisco flagship CMTS, the uBR10012.
Holobinko adds that BigBand is talking with Docsis modem chip players -- meaning Texas Instruments Inc. (NYSE: TXN) and Broadcom Corp. (Nasdaq: BRCM) -- about including that software client on their chips.
For now, BigBand doesn’t have much to worry about, anyway, at least when it comes to having to comply with a new set of specs. There's no such effort underway at CableLabs, according to David Reed, the R&D house's chief strategy officer. But he didn't completely rule one out, either.
"We are not at this moment creating a [cable IPTV] spec," he says. "If a consensus would emerge around something, we'd take that to our members. On the broadband side, we want to make sure we're trying to bring the best technology available to the cable operators."
And Comcast Corp. (Nasdaq: CMCSA, CMCSK), the largest MSO in the land, is evidently looking at all of the options on the table. At last month's Society of Cable Telecommunications Engineers (SCTE) Conference on Emerging Technologies, MSO senior fellow Weidong Mao said Comcast is still weighing which approach makes the most economic and technical sense. (See The Cable Show '09: 5 Takeaways .)
— Jeff Baumgartner, Site Editor, Cable Digital News