DOCSIS 3.1 Makes DebutDOCSIS 3.1 Makes Debut

As promised at SCTE Cable-Tec Expo last week, CableLabs has now released its DOCSIS 3.1 specification, just in time for Halloween.

The new D3.1 spec, crafted by CableLabs to be the roadmap for "a new generation of Docsis technology," raced from early concept to completed reality in barely a year, breaking all sorts of standards speed records. While Matt Schmitt, director of DOCSIS specifications for CableLabs, describes the specification as a "living document," the release means that silicon and equipment vendors can begin preparing prototype products for testing in early 2014. (See Docsis 3.1 Spec Out in Time for Halloween.)

DOCSIS 3.1 is focused on delivering several very specific benefits to cable operators. First and most notably, it enables greater capacity and speed, with support for up to 50 percent more data throughput over the same spectrum. Cable providers will be able to deliver up to 10 Gbit/s speeds in the downstream and 1 to 2 Gbit/s in the upstream.

Further, the new broadband spec decreases the cost per bit for data delivery by improving the efficiency of spectrum use. It uses Active Queue Management to decrease latency in the network. Plus, it increases energy efficiency in cable modems.

Finally, CableLabs has drafted DOCSIS 3.1 so that new cable hardware will be compatible with earlier DOCSIS technology. That should make it relatively easy for cable operators to migrate to the new specification.

CableLabs is emphasizing the fact that DOCSIS 3.1 will bring benefits to MSOs, even if they don't make any upgrades to the cable plant. For example, Schmitt told Light Reading last week that cable companies should "reasonably get an average of 25 percent or more upstream capacity out of existing plant," simply because DOCSIS 3.1 uses spectrum more efficiently.

On the other hand, if cable operators do invest in plant upgrades, then there is an immediate return on investment. If an MSO does a mid-split, for example, any D3.1 modems already deployed will be able to take immediate advantage of spectrum above the 42MHz line for upstream data transport, Schmitt said.

Of course, there are challenges ahead for DOCSIS 3.1 deployments, including the fact that it will be difficult to test new D3.1 modems without new cable modem termination system (CMTS) devices in place. However, many leading cable operators are eager to bring DOCSIS 3.1 to market, which means they will likely do their best to help smooth the transition. “MSOs like to get out in the field as soon as they can,” Schmitt noted.

Speaking at last week's DOCSIS 3.1 Engineering Symposium in Atlanta, Jeff Finkelstein, executive director of strategic architecture for Cox Communications Inc. , said his company is willing to do "anything we can do to help." Jorge Salinger, vice president of access architecture for Comcast Corp. (Nasdaq: CMCSA, CMCSK), said MSOs should plan now to put Docsis 3.1 hardware in the budget for 2015.

CableLabs has made the full DOCSIS 3.1 specification available for download on its website. The R&D group says that "As soon as prototypes are available, CableLabs will facilitate interoperability testing of products at its labs to help equipment manufacturers prepare for certification and qualification."

— Mari Silbey, Special to Light Reading Cable