Comcast Preps Docsis 3.0 Trials

Comcast Corp. (Nasdaq: CMCSA, CMCSK) is looking to begin Docsis 3.0 trials this year, with deployments possibly following in 2008, according to Tony Werner, the MSO's executive vice president and chief technology officer.

Werner discussed those plans and other elements of Comcast's technology strategy Tuesday during the MSO's analyst and investor day.

Werner did not say where Comcast would trial or deploy the new platform, but did note that those decisions would be based on certain business requirements, and pointed out that 3.0 can be targeted to specific portions the market.

He didn't say as much, but it's expected that Comcast and other MSOs, will apply 3.0 first in markets where telcos, especially Verizon Communications Inc. (NYSE: VZ), have deployed fiber-to-the-home networks.

Docsis 3.0 is an emerging CableLabs specification that will use channel bonding to produce broadband speeds greater than 100 Mbit/s. It's also designed to support IPv6, IP multicast, and other advanced IP features.

The faster speed isn't the only benefit of Docsis 3.0. According to Werner, 100-Mbit/s cable modem service tiers will provide similar cable modem termination system (CMTS) economics to today's 6-Mbit/s tiers.

Werner spent the bulk of his time Tuesday discussing cable capacity requirements for future services and the "levers" Comcast can pull to ensure it has plenty of bandwidth to throw at them. Some levers he cited included node splits, digital optimization, and switched digital video (SDV).

Node splits, he said, can be used to "surgically" add capacity to service areas, a move usually driven by downstream applications such as high-speed Internet and video-on-demand (VOD).

This year, about 65 percent of Comcast's node splits are of the cheapest "logical" variety, which cost about $3.35 per home passed and enable a tripling of capacity. About 25 percent are "modular" splits ($8 per home passed), and only 10 percent are "physical" node splits, which, at about $26 per home passed, are the most expensive of the lot.

Comcast is also exploring the bandwidth efficiencies afforded by variable bit rate VOD, a technology being championed by companies like Imagine Communications . (See Imagine Connects With SeaChange .)

Another lever in Comcast's arsenal is SDV, a technology the MSO will first test in parts of Denver and New Jersey. (See Comcast Reveals SDV Test Beds.)

Citing Comcast's own research, Werner said that, out of the 200 least-popular cable channels, a maximum of 40 are being watched at any given time. If those viewing patterns hold up, Comcast "can start stacking additional channels almost to infinity" without increasing capacity, Werner said.

By applying "conservative assumptions," Werner estimated that Comcast could free up 78 MHz of spectrum using a mix of SDV, analog-to-digital migration, reclaiming bandwidth from legacy apps, and advanced compression (MPEG-4).

— Jeff Baumgartner, Site Editor, Cable Digital News