DOCSIS 3.1 Speeds Ahead

DOCSIS 3.1, the new CableLabs-led platform that promises to deliver multi-Gigabit speeds without requiring operators to pull fiber all the way to the home, has made significant progress since its product specifications were issued last fall.

But don’t be fooled. There’s still a long road ahead before DOCSIS 3.1-based products will be ready for interoperability testing, a hurdle that will need to be overcome before real-world deployments can begin.

In fact, most people close to the DOCSIS 3.1 action don’t see large-scale rollouts starting until 2017.

Still, the project has been moving ahead at an accelerated rate compared to the industry’s shift from DOCSIS 2.0 to DOCSIS 3.0, a platform capable of getting cable operators within shouting distance of 1 Gigabit-per-second throughputs (at least downstream).


Thanks to the specter of Google Fiber and ongoing pressure from Verizon Communications’ FiOS, the big initial driver for DOCSIS 3.1 will be enabling throughputs that extend beyond 1 Gbps. The 3.1 spec is also expected to become the basis for fullfledged IPTV services.

Even further down the road, DOCSIS 3.1 will usher in cable’s broader all-IP transition, setting the stage for a platform capable of supporting capacities of 10 Gbps downstream and up to 2 Gbps upstream.

DOCSIS 3.0 still has plenty of legs left, but it isn’t graced with the data e fficiencies envisioned by D3.1, which will rely on blocks of orthogonal frequencydivision multiplexing (OFDM) subcarriers and a bandwidth-saving forward error correction scheme called Low Density Parity-Check (LDPC).

This pairing should allow cable to use higher orders of quadrature amplitude modulation (QAM) and squeeze more bits into the broadband pipeline. If all works as promised, D3.1 should boost cable’s spectrum efficiency by about 50%, giving MSOs even more headroom for advanced services.

So when will DOCSIS 3.1 be ready for primetime?

Estimates vary, but most don’t see DOCSIS 3.1 reaching scale deployments until 2016 or 2017.

Joe Cozzolino, senior vice president and general manager of video infrastructure at Cisco Systems, expects to see trials underway toward the second half of 2015, predicting that it’s “likely” that the initial batch of 3.1-based chips will require respins. He’s hopeful there will be trial activity by the second half of 2015, some initial deployments in 2016, and then a “ramp up” in 2017.

“Real deployment” of DOCSIS 3.1 could get underway by mid-2016, with mass deployments getting underway by 2017, Patrick Tierney, senior director of marketing for MaxLinear’s cable product line, agreed.

Arris will be doing “extensive testing of DOCSIS 3.1 this year and next,” senior director of CMTS product Jeff Walker said, predicting that 2017 will be “when things really start to get going.”


CableLabs issued the initial product specs for DOCSIS 3.1 last October, providing enough guidance for equipment makers and silicon suppliers to spark development. CableLabs published their “issue two” release on March 20, documentation that fine-tuned the specs and ironed out some “remainder issues,” Dan Rice, CableLabs’ senior vice president of network technologies, said.

The latest release bakes in some new features, including an energy-saving mode for DOCSIS gear and clarifications as to how portions of the specs should be interpreted, including how to measure power in OFDM channels, something new to the DOCSIS realm.

Looking ahead, CableLabs is also working on DOCSIS 3.1’s operational support systems (OSS) specs, which serve as the back-o ce systems for the platform. D3.1 Those specifications will be released this summer, Rice said.

A big, important project underway is the Acceptance Test Plans (ATPs) for DOCSIS 3.1, which will be used to verify that cable-modem termination systems (CMTSs) and modems conform with the specs. The hope is to have a draft version complete this summer, and to start “plug-fest” testing in the fourth quarter and possibly full-on interoperability tests, if the CMTS and modem equipment are found to be mature enough.

“I’m pretty encouraged by the progress we’re seeing out there,” Rice said.

Here’s a progress snapshot from the supplier side of DOCSIS 3.1.


The three known companies that are developing DOCSIS 3.1 silicon — Broadcom, Intel and STMicroelectronics — have not announced specific roadmaps for the new specs. Broadcom declined to talk about DOCSIS 3.1 for this story, while industry sources said STMicro, which was late to the game with DOCSIS 3.0, will be redoubling its efforts in the hopes of being out in front with DOCSIS 3.1.

MaxLinear, a company with historic ties to Intel, is working on its new RF front end for DOCSIS 3.1 silicon, and is developing a joint reference design based on Intel’s next-gen “Puma” chip, Tierney said.

“Silicon development is going well,” Tierney said, noting that MaxLinear expects to offer samples by the end of this year with initial prototypes emerging by the first half of 2015.


On the network end, Arris, which completed its acquisition of Motorola Home about a year ago, will center its DOCSIS 3.1 efforts on the E6000, a super- dense CMTS that is evolving into a full Converged Cable Access Platform that will perform the function of the CMTS and the edge QAM and handle cable’s full slate of voice, video and data services.

At this week’s event, Arris will demonstrate the E6000 supporting a 192 MHz-wide OFDM channel (again, the kind that will be used by DOCSIS 3.1), as well as 32 single-channel QAMs — with 24 of those QAMs carrying DOCSIS 3.0 tra c and eight used for video delivery. Arris will show all of that being served from a single RF port.

Cisco Systems, meanwhile, is placing a big D3.1 bet with the cBR-8, an integrated CCAP.

“When we come out with the cBR-8, it will be truly 3.1-ready at the line-card level,” Cozzolino predicted, noting that Cisco is developing a D3.1 RF module that can be swapped in for the existing DOCSIS 3.0 RF board. “It makes for an easy upgrade … for 3.1.”

The cBR-8, currently in customer lab testing, is slated for a commercial release by the first quarter of 2015, according to Cozzolino.

Among other recent vendor activity, Casa Systems introduced a DOCSIS 3.1-based upstream module for its C100G and C10G CCAPs that supports a wider upstream block — from 5Mhz to 100 MHz.


DOCSIS 3.1 modem makers can’t move forward until they have new silicon in hand, but some companies are planning to be more aggressive than others.

Netgear, which has developed D3.0 modem and gateway models that can bond 24 downstream channels and 8 upstream channels, will focus efforts on new D3.1 products and will spend fewer resources on developing products that can bond up to 32 downstream channels — the new channel-bonding benchmark for 3.0-based modems.

“We’re being very aggressive on DOCSIS 3.1,” Naveen Chhangani, director of product management for Netgear’s service-provider business, said. He expects 32-by-8 channel configuration for D3.0 modems to have a “very short life.”

“The industry doesn’t want another transition, unless DOCSIS 3.1 has some major challenges,” Chhangani said, noting that Netgear is working with three chip suppliers — Broadcom, Intel and STMicroelectronics.

Not all modem vendors share Netgear’s near-term enthusiasm for DOCSIS 3.1.

Hitron Technologies Americas, one of the first vendors to develop DOCSIS 3.0 modems capable of bonding 24 downstream channels and eight upstream channels, will be “hardpressed to justify the resources to be first to market [with DOCSIS 3.1], if there’s limited opportunities in the near-term,” chief technology officer Greg Fisher said.

“We don’t see a super-clear path here,” Todd Babic, Hitron’s chief sales and marketing o cer, added. “It’s heavily up for debate.”

Hitron may hold off and let other vendors with both DOCSIS CMTS and modems work out the technical and interoperability kinks and then jump in as a “fast follower” as the market ripens, Fisher said.

Another challenge will be hitting the price targets desired by operators.

The first D3.1 modems on the market will be hybrids that can support DOCSIS 3.0 tra c as well as OFDMbased channels for D3.1.

Fisher suggested that MSOs are urging vendors to develop these combo products and sell them for the same price as a DOCSIS 3.0-only device, a tall task (and perhaps an unrealistic target, particularly in the short term), when factoring in the development costs and the addition of new hardware, power requirements and silicon.

It could take two years “at the least” for a hybrid product to meet the same cost of a current 3.1 modem, in Fisher’s view, and that’s only after those products go through a full silicon cycle.

MaxLinear’s Tierney agreed that DOCSIS 3.1 modems “does add a little bit of cost. But we’re trying to integrate [components] to reduce those costs so that the difference will be minor.”

This Date in DOCSIS 3.1: Milestone Moments

May 14, 2012: During a webcast aimed at teeing up its plans for The Cable Show, Cisco Systems executives hint that CableLabs is working on a successor to DOCSIS 3.0 that will push the boundaries of cable’s upstream and downstream capabilities. At the time, CableLabs declines to confirm any such efforts are underway, though industry chatter is all about the coming of a “DOCSIS 3.x” spec.

Oct. 18, 2012: At a standing-room only event at the SCTE Cable-Tec Expo in Orlando, Fla., CableLabs and top MSO engineers formally unveil DOCSIS 3.1 as its next-gen specification effort for data-over-cable services, targeting the potential to support 10 Gbps downstream and at least 1 Gbps in the upstream. CableLabs also announces an accelerated plan to complete the core DOCSIS 3.1 specs in 2013.

June 10, 2013: Speaking at The Cable Show in Washington, D.C., top cable-engineering executives claim that the efficiencies of DOCSIS 3.1 could delay tricky “mid-splits” of the upstream. D3.1’s use of OFDM “is a godsend in the upstream,” Tony Werner, Comcast executive vice president and chief technology officer, said on a tech panel.

Oct. 24, 2013: At SCTE Cable-Tec Expo, CableLabs officials said the first generation of DOCSIS 3.1 modems will carry a minimum confi guration that will support max downstream throughputs of 4 Gbps to 5 Gbps downstream, and 1.5 Gbps upstream via a minimum-channel bonding configuration of 24-by-8 on the D3.0 side, and the ability to tie together two channels/blocks of OFDM spectrum at 192MHz-wide each, and two 96MHz-wide upstream channels.

Oct. 30, 2013: CableLabs releases the product specs for DOCSIS 3.1, beating its year-end deadline by two months, and announces plans to complete the networking-management specs for D3.1 by sometime in 2014.

March 20: CableLabs issues a new version of the specs, with minor tweaks and refi nements. Further refinements are expected this summer.