The next standard for cable broadband is now due by 2020.

For over a year, the cable industry has been stalled after deciding to slash investment in broadband while enduring indecision and confusion over the next generation of cable broadband.

At issue is a simmering disagreement — rare for the usually unified cable industry — about the next generation of cable broadband, dubbed DOCSIS 4.0.

Two sides have emerged. Cable giant Comcast has spent years gradually preparing its network for perhaps the last iteration of coaxial copper-delivered cable internet service. It has spent at least five years gradually pushing optical fiber closer to its customers, retiring additional coaxial cable and the amplifiers and other equipment associated with that technology. The result is a company ready to embrace Full Duplex DOCSIS, known as “FDX.”

FDX is designed to allow upload and download traffic to share the same spectrum, letting cable companies put internet service bandwidth to full use with maximum efficiency. Comcast wants FDX to be a central part of DOCSIS 4.0. The company has been working through a long-term plan to offer much faster internet service, including symmetrical broadband — unified upload and download speeds. This would erase the cable industry’s broadband Achilles’ heel: download speeds much faster than upload speeds.

To achieve FDX, cable companies have to push fiber much deeper into their networks, sometimes right up to the edge of neighborhoods. It also means eliminating signal amplifiers that help keep signals robust as they travel across older coaxial cable infrastructure. Engineers call this concept “Node+0” architecture, which means a network with zero amplifiers.

FDX gives the cable industry the opportunity of running a more robust broadband network, easily capable of 10 Gbps with an upgrade path to 25 Gbps later on. The downside is that it can be very expensive to implement, especially if a cable company has under invested in upgrades and not incrementally laid a foundation for FDX. Wall Street may balk at the upgrade costs. The logistics of readying degrading older infrastructure to launch FDX may be so onerous, some cable systems may find it more cost effective to scrap their existing hybrid fiber-coaxial (HFC) networks and switch to a state-of-the-art fiber to the home network instead. That is precisely what Altice USA is doing with its Cablevision/Optimum system in New York, New Jersey, and Connecticut.

Charter Communications, along with many other smaller cable operators, have been pushing an alternative to FDX that is likely to cost much less to implement. Extended Spectrum DOCSIS (ESD) is designed to work over existing cable systems, including those that still rely on amplifiers and aging coaxial cable. Instead of allowing internet traffic to share bandwidth, ESD follows the existing standard by keeping upload traffic on different frequencies than download traffic. It simply extends the amount of bandwidth open to both types of traffic, which will allow cable systems to raise speeds. ESD will dedicate frequencies up to 3 GHz (and higher in some cases) for internet traffic. DOCSIS 3.1, the current standard, only supports internet traffic on frequencies up to around 1.2 GHz. ESD will also allow cable companies to raise upload speeds and should support up to 10 Gbps downloads. But there are some questions about how well ESD will support 25 Gbps speed and the condition of the cable company’s existing coaxial network will matter a lot more than ever before. A substandard network will cause significant speed degradation and could even disrupt service in some cases.

Despite the limitations of ESD, many cable companies consider its low implementation cost a principal reason to support it over FDX.

For much of this year, cable companies have put upgrades on hold as the industry sorts out which direction DOCSIS 4.0 will take. Equipment manufacturers and vendors have resorted to layoffs and cutbacks and have signaled neither Comcast nor other cable companies are big enough to justify different DOCSIS standards supporting FDX or ESD.

Comcast and Charter are the two largest cable companies in the United States.

Therefore, the cable industry has informally decided DOCSIS 4.0 will need to support both FDX and ESD under a single specification, with next generation cable modems and equipment capable of supporting either technology. At a joint pre-Cable-Tex Expo conference held on Monday, executives from Comcast and Charter appeared to support the new unified approach to DOCSIS 4.0.

John Williams, vice president of outside plant engineering and architecture at Charter Communications, told attendees cable companies need to support both FDX and ESD and stop taking an “either/or” approach.

“In order to do this, we need to look at the synergies and embrace ESD and FDX as the next generation of HFC,” Williams said. “It’s all about scale.”

Charter has been significantly challenged historically because its own legacy cable systems were often behind the times and sometimes dilapidated. Its 2016 acquisition of Time Warner Cable and Bright House Networks only complicated things further, because neither operator had a reputation for using state-of-the-art HFC technology. Costly upgrades have been underway at many Charter-owned cable systems since the merger closed, some still ongoing.

Robert Howald, part of Comcast’s network upgrade team, called the emerging DOCSIS 4.0 standard a “perfect complementary pair” of FDC and ESD. He noted both approaches will allow cable systems to boost speeds to at least 10/10 Gbps, with faster speeds in the future.

Howald pointed out Comcast is already testing FDX technology in Connecticut and Colorado, working out bugs and unexpected technical challenges.

“We feel like we’ve significantly de-risked some of the technology components of FDX,” Howald said. “We felt really good about what we saw in the field.”

What is Full Duplex DOCSIS? This video from CableLabs explains the technology and how it differs from other DOCSIS cable broadband technology. (1:58)

Despite assurances from FCC Chairman Ajit Pai that the repeal of net neutrality would inspire cable operators to increase investment in broadband, a year-long virtual spending freeze by the nation’s top cable operators has resulted in a major vendor pulling out of the next generation cable broadband standard until there are signs cable companies are prepared to spend money on upgrades again.

Cisco Systems has confirmed to Light Reading it has ceased investment in Full Duplex DOCSIS technology that would allow cable customers to get the same upload speed as download speed.

“Cisco has internally communicated that we are suspending further investment in Full Duplex DOCSIS (FDX) until the market timing, ecosystem development and size of the opportunity can be quantified,” a Cisco spokesperson said in a statement to Light Reading.

The news is a significant blow to the cable industry’s plans to upgrade to 10 Gbps capacity and a growing desire by customers to get much faster upload speeds than are currently available.

Cisco blamed its pullback on the cable industry’s lack of investment in broadband upgrades and an uncertain timetable when major cable companies including Comcast, Charter, Cox, and others will announce specific plans for future upgrades.

FDX has already been the victim of delays. Originally planned as an incremental upgrade for DOCSIS 3.1, FDX is now scheduled to be included in CableLabs’ DOCSIS 4.0 specification, which is not expected to be released for a few years. FDX will be one of several new features incorporated into the next cable broadband standard, which will allow for low latency connections and an expanded amount of coaxial cable spectrum that can be devoted to broadband services.

The cable industry has been taking a sober look at the costs associated with adopting FDX, which includes scrapping a significant amount of coaxial cable and pushing fiber optic technology much closer to customers. Cable systems that want to move towards FDX will have to remove amplifiers that maintain signal strength between the fiber optic connection and the coaxial cable entering customers’ homes. In some cases, this will mean removing multiple amps from the cable system and stringing new fiber optic cables deep into neighborhoods. This is known as node+0 architecture. Moving towards node+0 is expected to be both costly and labor intensive, and some large cable systems and investors are balking.

“There are a lot of operators who have no intention of getting to a node+0 environment in next 10 years,” Tom Cloonan, chief technical officer of Arris’ Networks Solutions unit, told Multichannel News last fall. “It’s going to take a while to run fiber deep enough to get to node+0.”

To date, the only major cable operator that has definitively backed moving to node+0 is Comcast. Other cable companies, notably Cox Communications, are seeking a much cheaper solution to manage upgrades.

Extended Spectrum DOCSIS (ESD)
Image courtesy of: Huawei

An emerging alternative concept has emerged that can be implemented at a lower cost. Extended Spectrum DOCSIS (ESD) would essentially repurpose much of the bandwidth available over a coaxial cable solely to broadband service. DOCSIS 3.1 currently dedicates 1.2 GHz of spectrum for broadband. FDX would increase that to more than 1.8 GHz. ESD would devote as much as 3 (or possibly 6) GHz of spectrum for data transmissions. The cable system would devote as much as half of that spectrum for downstream traffic, the other half for upstream. Theoretical speeds in the future could be as high as 60 Gbps, and ESD will not require cable systems to ditch existing amplifiers. It will, however, force some cable systems to evaluate and replace at least part of their older coaxial cable network. ESD will be less forgiving of deteriorating cable than DOCSIS 3.1 is.

Unfortunately for Cisco, and other cable broadband equipment suppliers, ESD is still more theory than fact, and with cable operators demonstrating they are in no rush to move to either FDX or ESD, it will likely be several years before either technology becomes available to customers. Cloonan predicts ESD will not be implemented by cable systems until the mid-2020s.

The muddy waters over where the cable industry will ultimately plant the flag on next generation broadband upgrades means a lot of uncertainty for companies like Cisco, which has resulted in the company pulling out of developing FDX until there are assurances the cable industry has a timetable to implement it. The decision has also cost several Cisco employees their jobs. Multiple industry sources told Light Reading job cuts included 5-7 engineers dedicated to FDX, and some sources also report at least 40 employees in the cable access division of Cisco have also been let go.

If certainty does not return to the cable broadband market soon, Cisco could ultimately jettison much of its cable broadband technology division to focus on other technology growth areas.

The cable industry’s investment freeze is ironic because the Trump Administration’s FCC trumpeted its decision to repeal net neutrality, claiming it would inspire cable operators to accelerate investment in network upgrades. It appears the exact opposite has occurred.

Customers in several midwestern states around Chicago have today reported to Stop the Cap! Comcast has provisioned a speed change on their internet accounts with no advance warning or notice, raising download speeds from 100 Mbps to 150 Mbps but cutting upload speeds in half — from 10 Mbps before to 5 Mbps.

The changes seem to impact customers on the midwestern region Blast plan, which was sold in many areas around Chicago with speeds of 100/10 Mbps. Some customers logging into their accounts today see a unilateral plan change there as well — one they never asked for, reflecting the changed speeds:

Comcast has yet to respond to our inquiry about the confusion. Some customers are being told the plan change is in error, at least with respect to upload speeds. It would be unprecedented for Comcast to reduce customer speeds when making speed adjustments. If you are in the midwest and subscribe to this tier, what speeds are you getting today and what does your account profile show with respect to your current internet plan?

Updated 9:01pm EDT — Comcast has responded: “We plan to increase speeds in our central division next month and will share more details soon. It’s important to note that upload speeds will not change as part of that announcement.”

We remain uncertain why current speeds seem to have declined in some areas, which was not addressed.

Updated 9:15pm EDT — Some of the speed changes appear to be related to soft-launched speed upgrades in the Central U.S. division (Alabama, Arkansas, Florida, Georgia, Indiana, Illinois, Kentucky, Louisiana, Michigan, Mississippi, South Carolina, and Tennessee). The Performance tier that used to be 100/10 Mbps is increasing to 150/10 Mbps and the Extreme tier which was 150/20 Mbps previously is upgraded to 250/20 Mbps. You may need to briefly unplug your modem/gateway to receive the new speeds.

Updated June 27 11:10am EDT — Comcast has officially confirmed the upload speed reductions were in error. Customers that still find their upload speeds reduced should reset their modem, and upload speeds of at least 10 Mbps should be restored. The company’s forthcoming speed increases will maintain current upload speeds.

As gigabit internet becomes more common across the United States, some ISPs are seeking a speed advantage by offering even faster speeds to residential and business customers. On Tuesday, Nokia announced Frontier Communications and Rochester, N.Y.-based Greenlight Networks would be upgrading their fiber networks to the company’s XGS-PON solution, which can handle 10 Gbps upload and download speeds.

“Next Generation PON technologies such as XGS-PON are increasingly being deployed as demand for ultra-broadband applications and services continue to grow,” said Julie Kunstler, principal analyst at Ovum, in a statement. “Providing operators with the ability to use the same passive and active plants, XGS-PON solutions like Nokia’s can be quickly deployed and used to capture 10Gbps service opportunities that help operators to improve the return on their existing fiber network investments.”

Many existing fiber networks currently rely on GPON (gigabit passive optical network) technology — which allows one fiber in a bundle of fibers to service multiple homes and businesses. GPON networks are typically capable of download speeds of 2.488 Gbps and shared upstream speeds of 1.244 Gbps. Many ISPs using GPON technology typically offer fast download speeds, but often slower upload speeds.

Next generation XGS-PON allows up to 10 Gbps in both directions over existing fiber networks. In fact, the technology is future proof, allowing operators to immediately upgrade to faster speeds and later move towards Full TWDM-PON, an even more robust technology, without expensive network upgrades.

Most providers are leveraging XGS-PON technology to deliver symmetrical broadband — same upload and download speeds — to residential customers and to expand network capacity to avoid congestion. XPS-PON technology also supports faster-than-gigabit speeds than can be attractive to commercial customers.

Frontier intends to deploy Nokia’s technology in ex-Verizon markets in California, Texas, and Florida, beginning in Dallas-Fort Worth. It will allow Frontier to beef up its FiOS network and market stronger broadband products to Texas businesses. In Rochester, Greenlight will use the technology to upgrade its fiber service, which competes locally with Frontier DSL and Charter/Spectrum. Spectrum recently introduced gigabit download speed in Rochester. Greenlight can now expand beyond its 1 Gbps offering, but more importantly, increase its maximum upload speed beyond 100 Mbps.

“Greenlight is constantly looking at ways we can deliver new services that fit every customer need. We pride ourselves on offering the fastest internet speeds available in the markets we serve and Nokia’s XGS-PON technology will play a critical part in our ability to deliver these services to our customers,” said Greenlight CEO Mark Murphy. “With Nokia’s next-generation PON fiber solution we will be able to deliver the latest technologies, applications, products and services quickly and reliably to our customers and ensure they have access to the ultra-broadband speeds and capacity they require now and in the future.”

Nokia points out its XGS-PON technology may also be very attractive to wireless companies considering deploying 5G services. Extensive fiber assets available in area neighborhoods will be crucial for the success of millimeter wave 5G technology, which relies on small cells placed around neighborhoods and fed by fiber optics.