Cable's Wideband response against IPTV

Cable operators are concerned about telco fiber and IPTV deployments, but they also understand that these formidable competitors can’t move faster than their backhoes. So while the telcos dig and deploy new networks, MSOs are readying competitive responses.

At the top of the list is “wideband” technology that will boost DOCSIS cable modem speeds to more than 100 Mbit/s, fast enough to compete with any near-term telco fiber offering.

Today’s DOCSIS 1.0, 1.1, and 2.0 cable modem networks are only able to support data transmissions within a single downstream 6 MHz radio frequency (RF) channel, limiting maximum throughput to 38 Mbit/s per modem. To hike data rates, CableLabs is cooking up a new standard – DOCSIS 3.0 – that will enable a cable modem to simultaneously tune into multiple 6 MHz channels through packet bonding techniques. The approach creates a wideband channel that can support well over 100 Mbit/s downstream, although the bandwidth is shared among many cable modem users.

While wideband is a powerful weapon in cable’s arsenal, there’s a catch. The DOCSIS 3.0 specification isn't done. In fact, it's not even close. And once it is finished, there will be a long wait for cable modem termination systems (CMTSs) that qualify for DOCSIS 3.0 specification compliance. It is anticipated that it may take two to two-and-a-half years to get a qualified CMTS in the markets

That’s not good news for cable operators with AT&T or Verizon breathing down their necks in the early telco TV markets. The same is true for MSOs in Europe and Asia that are already hip-deep in high-stakes bandwidth battles. To speed up wideband availability, CableLabs recently floated the idea of an interim DOCSIS 2.0b initiative, but that has been nixed due to concerns that it would further delay DOCSIS 3.0 availability.

Hedging their bets, MSOs have been pressing the top DOCSIS CMTS and customer premises equipment (CPE) suppliers – Cisco Systems, Motorola and ARRIS – to produce pre-standard wideband gear for near-term deployment. Each of these three players now has pre-DOCSIS 3.0 wideband modems and CMTS solutions in field trials and plans general availability within 2006.

ARRIS and Motorola are following similar paths by enabling wideband capabilities through software upgrades to their existing CMTS cards and chassis. The benefit of this approach is that it allows cable operators to roll out wideband using existing CMTS hardware. Plus, the approach enables MSOs to create wideband links logically across existing channels already in use for DOCSIS 1.0, 1.1 and 2.0 services. This way, they can avoid allocating precious new spectrum for wideband services. Cisco, on the other hand, is implementing wideband using a modular CMTS (M-CMTS) configuration. ARRIS and Motorola say they have M-CMTS solutions on their roadmaps as well. They're also developing DOCSIS CMTS cards with decoupled upstream and downstream ports that will alleviate potential wideband efficiencies via traditional CMTS designs.

Motorola’s first announced wideband customer is StarHub. The Singapore MSO is now launching a wideband trial and plans to begin offering a 100-Mbit/s Internet service commercially by the end of 2006. Near-term availability of wideband gear is good news for cable operators, even if that only includes pre-DOCSIS 3.0 products. The trade-off is that in pre-standard configurations, cable operators must buy the modems and CMTS products from the same supplier to ensure compatibility. Initial wideband modems will also cost four to five times as much as today’s DOCSIS 2.0 models.

As a result, tech vendors expect that sales of pre-standard products will be modest at best. Until DOCSIS 3.0 is ready for prime time, MSOs are likely to deploy wideband only in residential markets facing intense competitive pressure, as well as for targeted business services.