June 18, 2007

Dawn of DOCSIS 3.0

Wideband’s great, but cable has plenty of ways to crank out higher speeds.

By Michael Grebb

Comcast chief Brian Roberts turned some heads last month at The Cable Show when he showed off cable’s DOCSIS 3.0-powered "wideband" future — a future where data rates will reach 150 megabits per second (and probably beyond). That’s pretty darned fast, and should make cable a formidable competitor for many years, even as AT&T and Verizon tout similar or greater speeds with their fiber rollouts.

But while the Roberts demo may have gotten folks fired up about CableLabs’ amazing work, it really only showcased what’s to come — not what’s out there now. The good news, however, is that there are many ways to crank out more capacity and speed on those data pipes even before DOCSIS 3.0 hits mass deployment. Vendors like Cisco, Motorola and others already offer several ways to maximize data speeds. I picked the brain of Jeff Walker, senior director of marketing for Motorola Connected Home Solutions, who said that in addition to old tricks like node splitting (hey, it still works!), cable operators have a number of options:

• Dynamic Load Balancing – The basic principle behind DLB is spreading the data workload across many machines (servers, processors, etc.) to increase the bandwidth available to everyone. In the broadband world, this can often mean a 30% gain in available bandwidth.

• Logical Channels – Operators can organize cable modems in the field into logical groups based on modulation and/or throughput profiles. With telcos pushing faster symmetrical speeds (partly because of DOCSIS 2.0’s inherent upstream limitations), this is a great way to bolster that elusive upstream path. Logical channels can allow MSOs to as much as double upstream data rates.

• Spectrum Overlay – Broadband access equipment provider Vyyo has been a big advocate of this technique, which involves leveraging higher frequencies on existing coax (3 GHz, for example). The result can greatly enhance both downstream and upstream speeds.

• Cable PON (passive optical network) – This technology involves migrating from a hybrid fiber-coax infrastructure to an all-fiber network. It’s perhaps the most ambitious (and most expensive) option for cable operators looking to stay ahead of the telcos. When it comes to existing cable systems, Motorola’s Walker admits that "it will be a long time before they really try to do this...But in the greenfield situations, it makes sense." (Disclosure: Moto heavily markets its own PON solution.) Walker says home developers are actually pushing fiber as a future-proof selling point.

The bottom line is that all the excitement over DOCSIS 3.0 wideband is justified: It’s a great long-term solution that’s backward-compatible with DOCSIS 2.0. But the cable industry has other ways to keep up with consumer bandwidth demands, now and in the future. Cable customers ain’t seen nothin’ yet.