The broadband industry is experiencing a transformative moment — one defined by unprecedented collaboration, groundbreaking technology and milestone achievements that set the tone for the future of connectivity. Today, we’re excited to highlight a convergence of firsts that represent significant strides in driving scalable, interoperable and high-performance broadband networks.

These advances were on full display at the latest Interop·Labs event, held June 9–12 at CableLabs’ headquarters in Louisville, Colorado. The event provided an opportunity for suppliers to verify interoperability between equipment designed to be compliant to the DOCSIS 4.0 specifications. The focus: speed and stability, two critical factors that directly impact the quality and reliability of broadband service.

A New Milestone: Uniting Innovation With Scale

In this blog post, we’ll walk through the key breakthroughs that made this interop a milestone event for DOCSIS 4.0 technology and the broadband industry as a whole.

1. 10 DOCSIS 4.0 Modem Suppliers

Interest in delivering modems into the DOCSIS technology ecosystem remains high, with 10 modem suppliers having attended a DOCSIS 4.0 interoperability event at CableLabs.

2. Three CCAP Core Suppliers Demonstrating Advanced Capabilities

In an industry first, three DOCSIS core suppliers attended the interop and demonstrated:

• Stable registration with multiple high-speed channels.
• Cable modem interoperability.
• High-speed throughput both upstream and downstream.
• Advanced service features.

The successful interop of multiple cores with the modems at the interop further proves that operators are no longer bound to a single core vendor solution. Instead, they can architect their networks based on performance, cost and feature alignment — without compromising on integration or scale.

3. Five RPD Suppliers Interoperating in a Single Network

Additionally, for the first time, five Remote PHY devices (RPD) were tested during the event and successfully achieved interoperability with the cores, reinforcing the maturity of the Distributed Access Architecture (DAA) ecosystem. Additionally, for the first time, five Remote PHY Devices (RPD) were tested during the event and successfully achieved interoperability with the cores reinforcing the maturity of the Distributed Access Architecture (DAA) ecosystem. This marks a major achievement for interoperability in a traditionally siloed space, where vendor lock-in could limit agility and innovation.

Each RPD supplier brought unique implementation characteristics to the table — ranging from management capabilities to different form-factors. The cores not only handled these diverse devices gracefully but also maintained service performance and control plane consistency while achieving high-speed data delivery.

4. Achieving 14 Gbps DOCSIS Downstream Throughput

The fourth major milestone is a technological leap forward: 14 Gbps of downstream DOCSIS throughput achieved across a multi-vendor network. This achievement leverages the full potential of DOCSIS 4.0 technology, DAA architectures, next-gen modulation (4096-QAM) and intelligent spectrum management.

This bandwidth benchmark isn't just a speed milestone — it’s a validation of the DOCSIS roadmap, demonstrating that hybrid fiber coax (HFC) infrastructure remains a future-ready platform that can compete with fiber on both performance and longevity.

Why These Firsts Matter

These achievements go beyond engineering milestones — they signal a new era of openness and agility in broadband infrastructure. For operators, this means:

• Faster innovation cycles due to supplier interoperability and innovation.
• Reduced operational risk via interoperable fallback options.
• Future-proof investments in scalable architectures like DAA and DOCSIS 4.0 technology.

For consumers and businesses, it translates to more reliable service, higher speeds and faster deployments of next-generation broadband.

Participants test their equipment for interoperability, with a focus on speed and stability, during the June 2025 event at CableLabs.

Key Contributors and Participants

Attendance at the event was strong, with new suppliers, new products and three operators on hand to observe demos and share their DOCSIS 4.0 network progress.

Suppliers included CommScope, Harmonic and Vecima, who brought DOCSIS 4.0 cores to the event. For the first time, we saw five Remote PHY Device (RPD) platforms from: Calian, CommScope, Harmonic, Teleste and Vecima. Eight DOCSIS 4.0 modem suppliers in attendance — Arcadyan, Askey, Compal, Gemtek, Hitron, Sagemcom, Sercomm and Ubee — brought multiple cable modem models.

Participating in the event were chipmakers Broadcom and MaxLinear, who brought local engineering support for their cable modem partners. Calian participated with its test solutions, and Microchip brought its clock and timing system.

Testing combined virtual cores, RPDs and modems from different vendors to verify performance and cross-compatibility. DOCSIS 3.1 and 4.0 devices were once again integrated to showcase interoperability between legacy and next-gen technology. Suppliers providing test equipment used these setups to verify their solutions.

Looking Ahead

This confluence of industry firsts is not an endpoint, but a foundation. With successful demonstrations of interoperability, performance and scalability, our industry is entering a period where the promise of next-gen broadband becomes reality — not just in labs, but in communities around the world.

The future is open, fast and here — and we couldn’t be more excited to play a part in building it.

Upcoming Events

The next phase of broadband promises faster speeds, greater reliability and seamless integration across today’s HFC networks. Another DOCSIS 4.0 interop is planned in August at CableLabs. Consider joining us to explore the possibilities firsthand.

Also, registration is now open for SCTE TechExpo25, happening Sept. 29–Oct. 1, 2025, in Washington, D.C. The theme of the industry-leading annual event is “Network (R)Evolution: Delivering the Seamless Experience.” Join us to explore how operators can thrive amidst the transformation across wireline, wireless and converged networks. CableLabs members are eligible to receive a complimentary full-access pass to SCTE TechExpo.

CableLabs is pleased to announce the certification of the industry’s first DOCSIS 3.1 Plus (DOCSIS 3.1+) device supporting four orthogonal frequency-division multiplexing (OFDM) channels. The certified device, developed by Vantiva, represents a key milestone in advancing broadband performance and capacity for cable operators worldwide.

The DOCSIS 3.1 specifications require support for at least two OFDM channels but have always included the option to support more; until recently, the available technology solutions did not support that additional capability. Devices identified as DOCSIS 3.1+ are certified to be compliant to the existing DOCSIS 3.1 specification with additional OFDM channels, extending the modem’s capabilities with increased downstream throughput (up to ~8-9Gbps).

By increasing the number of OFDM channels from two to four, the newly certified device significantly boosts potential bandwidth, improving user experience and opening up new service opportunities without expensive plant upgrades.

This achievement by Vantiva highlights the continued innovation in the broadband ecosystem and sets the stage for operators to begin delivering even greater speeds and capacity to their customers.

Why Certification Is Critical

This certification demonstrates both the readiness of the technology and the growing momentum toward more scalable, efficient network solutions ahead of full DOCSIS 4.0 deployments.

Although the DOCSIS 3.1 specification has been published for several years, certification remains an extremely important part of maintaining a reliable, interoperable ecosystem. Devices submitted to CableLabs often encounter issues during certification testing that require extensive troubleshooting and firmware changes before certification can be granted. This significantly reduces the amount of testing that needs to be conducted by operators prior to deployment, accelerating deployment. Therefore, operators rely on and choose devices that have been properly tested and certified at CableLabs.

Continuing the March Forward

In past years, DOCSIS technology has steadily advanced, driven by a strong ecosystem of member operators and vendors collaborating with CableLabs.

Every generation of the technology — from DOCSIS 1.0 to 3.0 and 3.1 to 4.0 — has enabled operators to deliver higher speeds, increased capacity, lower latency and more robust security. That momentum continues as CableLabs continues to define the future of DOCSIS networks and how that evolution fits into our broader strategy for member operators.

Learn more about CableLabs’ certification process and how DOCSIS technology has evolved over the years. To engage with us in our ongoing DOCSIS technology work, request to join a related working group or participate in a future Interop-Labs event.

At the recent DOCSIS® Provisioning of XGS-PON Interop·Labs event at CableLabs, suppliers of PON optical line terminals (OLTs) exercised their systems’ ability to configure XGS-PON optical network units (ONUs) via the use of DOCSIS-style configuration files. The event took place February 24–28 at our headquarters in Louisville, Colorado.

CableLabs member operators have long been familiar with the method of using a configuration file to provision services on a DOCSIS cable modem. Beginning a decade or so ago, DOCSIS-style configuration was also utilized by many operators to simplify the provisioning of IEEE EPON systems compliant to the DOCSIS Provisioning of EPON (DPoE) specifications. These DPoE virtual cable modem (vCM) config files enabled an operator to use the same service provisioning back-office systems that they originally deployed for DOCSIS cable modems to provision services on DPoE EPON networks.

Fast-forward to today, and many CableLabs member operators are deploying or preparing to deploy ITU-T-based PON technologies, including XGS-PON, 25GS-PON and 50G HSP.

Some XGS-PON OLT suppliers have now also adopted the vCM config file method for provisioning ONU services by adding a DOCSIS adaptation layer (DAL) software function to their system offering. The DAL solution performs the well-known cable modem DHCP and TFTP transactions on behalf of each ONU registering on each OLT managed by the system. The DAL parses the contents of each config file and translates those contents into directives on the OLT. This provides the OLT with the necessary details to complete the service configuration of a given ONU.

Using an OLT with a DAL capability isn’t the only method to configure services on each ONU. Other methods include the use of SDN-based procedures and protocols such as Netconf or OLT supplier-provided RESTful APIs. But the use of the DAL and DOCSIS-style config files can ease the transition of member operators into ITU-T-based PON technologies, without the need for wholesale replacement of the operator’s service provisioning back-office.

Supplier Participation in the Provisioning of XGS-PON Interop

We thank the supplier participants who helped make the February interop event so successful. The primary participants were XGS-PON OLT suppliers who showcased their DAL implementations.

These OLT suppliers included Calix, Harmonic and Nokia. In particular, Calix tested using their E7-2 OLT and DPx DAL. Harmonic brought their Pier OLT and cOS virtualized core software platform. And Nokia tested using their Lightspan MF-2 OLT with Altiplano controller and a DAL from their solution partner, ZCorum. As a bonus, Nokia demonstrated that the DOCSIS provisioning method can also be used to provision services on a 25GS-PON optical network unit (ONU).

In addition to the OLT supplier participants, MaxLinear was in attendance with their reference-design XGS-PON ONU, and TraceSpan participated with their NG-PON Xpert analyzer, whose DPoX Validation capability was instrumental for validating the correctness of the OMCI configurations that were set by the OLTs.

How the XGS-PON ONU Test Cases Unfolded

During the interop event, CableLabs provided an identical set of XGS-PON ONUs of various makes and models to each of the three OLT suppliers. CableLabs also provided a set of standard config files — one for each of the test cases defined in the interop test plan.

By utilizing a common set of ONUs and config files, we could see how each OLT-plus-DAL system reacted to a given config file on a given ONU. The overall goal of the event was to work towards a given ONU having an identical service configuration — for a given test case — across all the OLTs.

The test plan executed at this event was derived from the DOCSIS Provisioning of ITU-T PON tech report, which CableLabs published in December 2024. Test cases included basic HSD configuration of ONUs with a single Ethernet port as well as ONUs with multiple Ethernet ports. When configuring services on ONUs with multiple ports, a config file construct called a Cable Modem Interface Mask (CMIM) Classifier was utilized to control which ports on the ONU were active. Testing also included a triple-play (HSD, IP Voice and IP Video) test case, which utilized Differentiated Services Code Point (DSCP) traffic classifiers in the config file. A final test case that was executed from the interop test plan included the use of an ONU with an integrated eRouter functionality.

In cases where an OLT supplier was not initially able to successfully configure a given ONU for a given test case, we allowed the supplier to make customizations to the standard config file. This enabled the supplier to execute the test case and note where changes in their software might be needed to successfully use the standard config file in the future.

Each test case executed during the event made use of the lab’s 100GE traffic generation system, the lab’s standard DHCP and TFTP server infrastructure, and a PON analyzer to decode the ITU-T-specified ONU Management and Control Interface (OMCI) message exchanges across the PON. Many thanks to Charter Communications and TraceSpan Communications for supplying additional NG-PON Xpert analyzer units, enabling each OLT supplier test setup to utilize a dedicated analyzer.

Beyond the primary DOCSIS provisioning focus of this February event, we were pleasantly surprised that one of the supplier participants in this event brought OLT and ONU software versions that demonstrated partial compliance to the Cable OpenOMCI I01 specification. We look forward to seeing many more suppliers follow suit in the near future.

Applying the Lessons Learned

Overall, the results of the event were encouraging, with both established as well as new supplier entries into this product space showcasing their abilities to provide common service configurations across a wide variety of ONU makes and models.

The implementations exercised at this event indicate that these suppliers believe that a DOCSIS Provisioning of XGS-PON solution will be an important part of their product portfolio for the foreseeable future. We plan to take the lessons learned from this event and apply them to a future update of the DOCSIS Provisioning of ITU-T PON tech report.

Join the Next PON Interop

CableLabs is planning three more PON Interop·Labs events to be held in our Louisville, Colorado, labs in 2025. Our next event is scheduled for the week of April 28, 2025.

The April event will provide an opportunity for OLT suppliers to return with their DAL solutions to once again test ONU and config file interoperability. In addition, ONU and OLT suppliers with software implementations compliant to the Cable OpenOMCI I01 specification will be invited to exercise the capabilities defined in that specification.

As the world of broadband connectivity evolves, so does the technology that powers it. The evolution of DOCSIS technology has been a cornerstone of high-speed internet delivery, enabling service providers to meet the growing demands for faster and more reliable internet access. DOCSIS 4.0 technology represents the latest milestone in this journey, offering impressive speeds and new capabilities.

The latest Interop·Labs event, which took place Feb. 10–13 at CableLabs in Louisville, Colorado, showcased these capabilities and more, focusing on speed and stability — crucial factors in determining the quality and reliability of an internet connection.

A Bright Future for DOCSIS 4.0 Technology

DOCSIS 4.0 technology is poised to revolutionize broadband connectivity, offering significantly faster speeds, better efficiency and enhanced security. Its backward compatibility with existing DOCSIS 3.0/3.1 infrastructure makes it a flexible solution for both service providers and consumers.

As with any major technological leap, ensuring smooth interoperability between old and new systems is key to a successful transition. By offering a scalable, future-proof solution that can be deployed gradually, DOCSIS 4.0 technology allows operators to gracefully migrate to these new products.

Why Speed and Stability Are Critical

Speed refers to how quickly data is downloaded or uploaded, often measured in megabits per second (Mbps), and plays a key role in activities such as streaming, gaming and video conferencing. Stability, on the other hand, is about the consistency of that connection.

A stable connection ensures that users experience minimal interruptions or slowdowns, even during peak usage times. Both high speed and stable performance are essential for seamless online experiences, especially in households or businesses that rely on multiple devices or heavy internet usage.

Key Contributors and Participants

The DOCSIS 4.0 specifications describe both frequency division duplex (FDD) and full duplex (FDX) modes of operation. For this interop, the first of 2025, new modems and RPDs that supported both modes (on the same device) were participants for the first time.

Attendance at the interop was high and included new suppliers and products, as well as two operators that joined to observe demonstrations, interact with the suppliers and discuss their own DOCSIS 4.0 network progress.

Suppliers included CommScope and Harmonic, who brought DOCSIS 4.0 CCAP cores to the event. For the first time, we saw new Remote PHY Device (RPD) platforms from three separate suppliers: Harmonic, Teleste and Vecima. Seven DOCSIS 4.0 modem suppliers — Arcadyan, Askey, Gemtek, Hitron, Sagemcom, Sercomm and Ubee — brought multiple cable modem models. Calian participated with its test solutions, and Microchip participated with its clock and timing system.

Broadcom has developed new chipsets that enable a device to operate in either FDD or FDX mode, under the control of the network. Another chipset supplier, MaxLinear, was also in attendance, exhibiting its latest DOCSIS 4.0 modem innovations.

Testing scenarios involved using a virtual core from one supplier, and RPDs and DOCSIS 4.0 cable modems from various other suppliers. The products were mixed and matched to verify interoperability scenarios and speeds through the system. As before, DOCSIS 3.1 and DOCSIS 4.0 devices were combined to demonstrate the cross-compatibility of existing and new technology. Suppliers providing test equipment used these setups to verify their solutions.

Broadband Service Enhancement

The February interop was another opportunity to drive interoperability between some of these new products/platforms and some existing ones, ensuring that the different systems and devices would seamlessly work together to exchange information. Interoperability is vital to enabling these devices to connect and interact. By fostering interoperability, the DOCSIS ecosystem continues to provide innovation and solutions to enhance broadband services, ultimately leading to better outcomes for consumers.

Remote PHY Interoperability

Although modems were the focus, the event also looked at the interoperability between DOCSIS 4.0 cores and RPDs. We branched into more and different configurations, moving beyond one-size-fits-all configurations. These products are going to be deployed in many scenarios, and going deeper into these various configurations will ensure flexibility as DOCSIS 4.0 technology moves into the field.

Join Us Soon

The next DOCSIS 4.0 interop is planned for the week of March 31 at CableLabs.

If you are a member or vendor attending CableLabs Winter Conference, join us for our two-part session “The What, Why and How of Future HFC Solutions.” We’ll explore the potential of future generations of DOCSIS networks, exploring how the evolution of the technology will support tomorrow’s hybrid fiber coax networks. This two-part session begins at 12:45 Tuesday, March 11.

With DOCSIS 4.0 technology, the future of broadband looks brighter, faster and more connected than ever before. The technology’s seamless integration into current systems ensures that consumers will continue to benefit from fast, reliable internet — no matter where they are on their broadband journey.

At the latest DOCSIS 4.0 Interop·Labs event — which took place Nov. 4–7 at CableLabs’ headquarters in Louisville, Colorado — equipment suppliers showcased their efforts to deliver on the 10G platform through DOCSIS 4.0 technology. All four 10G pillars were on display: faster speeds, lower latency, enhanced security and increased reliability. These pillars were all designed into the DOCSIS 4.0 specifications, and we’ve reached the point at which the products simply work.

We want to thank the participants who helped make the event successful and once again helped us achieve a high level of productivity. To recap the major themes of the event:

• Speeds are rock solid. Demonstrations boasted downstream speeds faster than 9 Gbps that were limited only by the single 10 Gbps interface on the modems. Upstream speeds can exceed 2 Gbps on and go even higher.
• The new focus is interoperability. Products are maturing, and suppliers are differentiating their offerings. As operators continue to seriously develop deployment scenarios, we want to ensure that the specifications are clear enough to handle real-world deployment, including specific configurations, corner cases and race conditions. Four operators attended this interop to provide guidance on deployment scenarios. Much effort went into exercising interoperability and identifying areas for work.
• Energy efficiency is on the rise. A burgeoning trend at this interop was energy management. New features will benefit consumers by providing options to conserve energy in various scenarios.
• Reliability is a reliable theme. We continue to examine the copious data available from the modems — in particular, DOCSIS 4.0 cable modem Proactive Network Maintenance (PNM) functions that can be used to increase the reliability of service offerings.

Supplier Participation

Attendance at the interop was high, as it offered the last best opportunity to get this work in before the 2024 holiday season arrived. The aforementioned operators who joined us to observe demonstrations went out of their way to interact with suppliers and talk about their own DOCSIS 4.0 network progress.

Among the suppliers were CommScope and Harmonic, both of which brought DOCSIS 4.0 cores to the interop. There were also three 1.8 GHz remote PHY devices (RPDs) from CommScope, Harmonic and Vecima Networks. In addition, seven DOCSIS 4.0 modem suppliers — Arcadyan, Askey, Gemtek, Hitron, Sagemcom, Sercomm and Ubee Interactive — brought multiple cable modem models. Calian participated with its suite of DOCSIS technology analyzers and tools.

Remote-PHY Interoperability

The DOCSIS modem termination system (CMTS) has been virtualized, and the software portion is referred to as the core. The physical layer of the CMTS has moved to the RPD in the fiber node. In other words, the CMTS has been disaggregated, and the core and RPD can (and will) come from different suppliers. The modem can come from yet another supplier. These three pieces need to work together to provide service.

At our interop events, we like to delve into multiple real-world configurations. The core calls the shots and configures the RPD for the downstream and upstream signals, and then the core manages the DOCSIS cable modems. Flexibility is built into this scenario, however, and we’re constantly working to get everything right and interoperable. It’s for this reason that operators attend the interop events — to clarify how DOCSIS 4.0 technology can be introduced to the networks, including backward compatibility with existing services.

Energy Management

Energy management is an important function for cable modems. DOCSIS cable modems and cores support a low-power energy mode called the Energy Management (EM) mode. During idle times, when a single upstream and downstream channel can meet a user’s data-rate demand, the cable modem switches to EM mode. When the modem requires a higher data rate than the reduced set of channels can provide, the core instructs the modem to return to the larger transmit-and-receive channel set.

EM mode can also be used during a power outage — for example, when a modem goes into battery back-up but continues to provide digital phone service. In this scenario, EM mode can conserve battery power when the traffic is low, exhibiting minimum impact on normal service, to prolong access to digital voice service, especially the 911 emergency call service.

The EM feature shows how people rely on their broadband connection for all services, not just web and email. The feature also reveals how DOCSIS technology has evolved to address these needs as a broadband service of choice.

Proactive Network Maintenance

PNM is an important function that increases network reliability. We always look at the PNM data available from DOCSIS device, because it’s a sign of product maturity. This PNM data enables the most efficient operation of the coaxial cable network, keeping the data levels at their peak by using the more efficient orthogonal frequency-division multiplexing (OFDM) and OFDM access (OFDMA) signals, and allowing the diagnosis and maintenance of the network before consumers ever notice an issue.

Join Us Next Time!

We’ve gone beyond the basics of the four pillars. The focus of our DOCSIS 4.0 interops is now interoperability, interoperability and more interoperability! These products are soon headed to the field, in various configurations with multiple suppliers’ products having to work together. And this work will continue into 2025 as DOCSIS 4.0 technology comes into use.

The next DOCSIS 4.0 interop event is planned for the week of Feb. 10, 2025, at CableLabs’ headquarters in Louisville, Colorado. The event will provide an opportunity for new suppliers and new products as we kick off the new calendar year.

And don’t forget: Right around the corner in March 2025 are CableLabs Winter Conference and Smaller Market Conference.

A fundamental enabler in connecting people around the globe, DOCSIS technology has empowered millions to live, work, learn and play. Since the days of the first DOCSIS 1.0 cable modems (CMs) almost 30 years ago, DOCSIS technology has continued to evolve, benefitting from a robust ecosystem of operators and vendors working together with CableLabs to develop technologies that enable differentiated services.

Just in the last decade, operators have moved from DOCSIS 3.0 technology to deploying DOCSIS 3.1 technology at scale. Now, in 2024 and going into 2025, operators are evaluating, starting initial deployments and rolling out DOCSIS 4.0 networks.

Because DOCSIS networks always provide backward compatibility, older modems can coexist and provide service to customers even after the operator has moved ahead to newer technology. This is critical as modems often live in the network for many years.

Work at CableLabs is underway to define the future of DOCSIS networks and the technology’s role in our broader network strategy. For a better understanding of what’s ahead, let’s discuss some of the recent evolutionary steps in the DOCSIS technology ecosystem.

What Is DOCSIS 3.0?

DOCSIS 3.0 networks introduced channel bonding and allowed operators to bond multiple single carrier quadrature amplitude modulation (SC-QAM) channels together (in both the upstream and downstream directions) to increase the available speeds at the CM. A DOCSIS 3.0 CM with 32 SC-QAM channels in the downstream and four SC-QAM channels in the upstream could theoretically get a peak throughput of 1 Gbps/100 Mbps (downstream/upstream) on the network, though actual service tiers offered on individual networks may have differed.

What Is DOCSIS 3.1?

DOCSIS 3.1 technology introduced orthogonal frequency division multiplexing (OFDM) and orthogonal frequency division multiple access (OFDMA) technology. A DOCSIS 3.1 CM, typically with two OFDM channels and 32 SC-QAM channels in the downstream and two OFDMA channels and four SC-QAM channels in the upstream, theoretically would get to a throughput of 5 Gbps/1.7 Gbps on the network. Actual service tiers offered by operators would be dependent on their network configuration and channels and service tiers enabled.

DOCSIS 3.1 technology allowed operators to enable gigabit and multigigabit service offerings (downstream) in their markets. Depending on the operator upgrades to their outside plant, the upstream capacities could range from 100 to 250 Mbps on a low-split plant, to 250 to 575 Mbps on a mid-split plant, to 1.5 to 1.7 Gbps on a high-split plant.

What Is DOCSIS 3.1 Plus?

In the last year, vendors have built DOCSIS 3.1 cable modems with additional downstream channel capabilities, going up from two, to four or even five OFDM channels. This is a welcome product extension beyond the minimum device capabilities described in the DOCSIS 3.1 specifications.

CableLabs, along with our member operators in the industry and NCTA, are coalescing around the term DOCSIS 3.1 Plus (DOCSIS 3.1+) CM to identify this new class of modems. DOCSIS 3.1 Plus CMs will enable up to 8 or 9 Gbps on the downstream — again, depending on the spectrum available in the cable plant for an operator. Typically, a software upgrade is needed on the CMTS to enable the additional channels. Alternatively, an operator can also seed the network with DOCSIS 4.0 CMs, which have a minimum of five OFDM channels, on existing DOCSIS 3.1 CMTS to support similar increases in downstream speeds.

What Is DOCSIS 4.0?

DOCSIS 4.0 technology is the latest generation of high-speed broadband solutions over hybrid fiber coax (HFC) networks. DOCSIS 4.0 technology catapults the broadband network speeds up to 10 Gbps downstream and 6 Gbps upstream.

DOCSIS 4.0 specifications build on the OFDM and OFDMA technology. It increases the spectrum available for the upstream and downstream and then fills them with more OFDM and OFDMA channels. The technology allows different outside plant upgrade paths to operators, a frequency division duplex (FDD) mode or a full duplex (FDX) mode of operation. For FDD mode, there are different upstream/downstream splits an operator can choose for their outside plant, each providing an increase in upstream/downstream capacity. FDX mode also enables flexibility in how operators size and utilize the FDX portion of the spectrum to meet the needs of their customers.

In an FDD plant, for an FDD CM, the upstream capacities could range from 4.2 Gbps (on a UHS-396 MHz plant), to 6 Gbps on a (UHS-684 MHz plant) and the downstream capacities could range from 9-10 Gbps. In an FDX plant, an FDX CM also can reach up to 6 Gbps on the upstream and 9-10 Gbps or more on the downstream. This is assuming a DOCSIS 4.0 CM has the required minimum support for five OFDM downstream channels and seven OFDMA channels. A CM with more channels and on a plant where the additional spectrum is enabled could get downstream speeds beyond 10 Gbps.

Current product developments also enable devices that can operate on both types of networks — either FDD or FDX (albeit not at the same time, as the outside plant will be configured for either one mode of operation or the other). In addition, a DOCSIS 3.1 CM can also be software upgraded to participate in an FDX network, known as an FDX-Limited or an FDX-L CM, with limited capabilities for operating within the FDX band. Though this CM’s peak speeds remain the same, it allows operators to use the FDX spectrum flexibly, for both DOCSIS 3.1 CMs and DOCSIS 4.0 CMs.

The DOCSIS Technology Evolution

CableLabs has hosted nine DOCSIS 4.0 Interop·Labs events since July of 2023, and more are planned for 2025. Each event offers a new, up-close look into how DOCSIS 4.0 equipment is maturing. Operators are busy evaluating and testing the different components that will need to be upgraded for a DOCSIS 4.0 network — taps, amplifiers, RPDs, CCAP cores and modems.

The industry remains focused on implementing and deploying the DOCSIS 4.0 technology into the broadband networks. Large-scale deployment of DOCSIS 4.0 technology will bring customers into the 10G era in the near future.

So, what's next? What will the next generation of DOCSIS technology look like?

Continuing Industry Collaboration

As we shift from the speed era into the experience and adaptive eras — an evolution highlighted in CableLabs’ Technology Vision — DOCSIS technology will continue to evolve as well. The cable operator community, the vendor community and CableLabs have all been thinking and conducting research on how DOCSIS networks should move forward for the next big leap in broadband technology.

There is much work to be done to define new generations of DOCSIS technology and what it will truly look like. As always, CableLabs — which owns the DOCSIS trademark — will work closely with its members and working groups to oversee the development of future versions of the technology.

The impact to the outside plant and the physical characteristics of the coax are important considerations. The technology development work will include analysis and decisions on the spectrum range we ultimately target (for example, 3 GHz or 6 GHz or 7 GHz), where the upstream/downstream/full duplex regions will be, as well as what the underlying physical layer technology (fidelity requirements, channel sizes, FEC, etc.) and what the potential MAC layer technology improvements are going to be.

It’s an exciting time to be in the connectivity business! CableLabs looks forward to collaborating with the ecosystem on future developments for DOCSIS technology.

Follow the CableLabs blog to stay up to date on these developments and our Interop·Labs events.

At the latest DOCSIS 4.0 Interop·Labs event, a record number of modem suppliers were on hand to delve deep into upstream speed and other aspects of the DOCSIS 4.0 specifications. We want to thank the participants who helped make the event successful and once again helped us achieve a high level of productivity.

We cannot highlight enough how CableLabs provides a neutral testing ground for suppliers and operators to come together and showcase compatibility across interfaces defined in our DOCSIS 4.0 specifications. The gathering of suppliers and products in one location is extremely valuable to the participants to see how the technology is being implemented across multiple platforms. The DOCSIS 4.0 specifications are proscriptive, yet there’s plenty of room for innovation to differentiate products and offerings.

Combining interoperability events for these technologies drives home the fact that compatibility across all system components is a high priority for the industry.

To recap:

• Everything is coming up gigabits!
• Downstream speeds faster than 9 Gbps through a DOCSIS 4.0 modem are the new normal, limited only by the availability of a single 10 Gbps interface on the modems.
• Upstream speeds now exceed 2 Gbps on DOCSIS 4.0 modems and can go higher.
• We continue to examine the copious data available from the modems — in particular, DOCSIS 4.0 cable modem Proactive Network Maintenance (PNM) functions.
• DOCSIS 4.0 security technologies are coming along nicely, and their recent availability showcases the advancing maturity of the products.

DOCSIS 4.0 technology is putting down a marker. These products are delivering on the promise of multi-gigabit speeds that will benefit consumers around the world. Among suppliers and operators in our labs, we’re seeing unprecedented passion for interoperability, for unrivaled speeds and for getting these products to market.

Record Supplier Participation

Attendance at the interop was high, including new suppliers and products. Three operators joined us to observe demonstrations, interact with the suppliers and talk about their own DOCSIS 4.0 network progress.

Among the suppliers were CommScope and Harmonic, which brought DOCSIS 4.0 cores to the interop. For the first time, we saw three 1.8 GHz Remote PHY Devices (RPDs) from separate suppliers including CommScope, Harmonic and Vecima Networks. Also, for the first time, eight DOCSIS 4.0 modem suppliers — Arcadyan, Askey, Gemtek, Hitron Technologies, Sagemcom, Sercomm, Ubee Interactive and Vantiva — brought multiple cable modem models. Microchip Technology participated with its clock and timing system. The availability of record numbers of both DOCSIS 4.0 RPDs and DOCSIS 4.0 cable modems shows that products continue to proliferate as these suppliers prepare for SCTE TechExpo 2024 later this month.

Testing scenarios involved using a virtual core from one supplier, and RPDs and DOCSIS 4.0 cable modems from various other suppliers. The products were mixed and matched to verify interoperability scenarios and speeds through the system. As before, DOCSIS 3.1 and DOCSIS 4.0 devices were combined to demonstrate the cross-compatibility of existing and new technology. Suppliers providing test equipment used these setups to verify their solutions.

Sustained Speed

Achieving a rate of 9 Gbps (or faster) downstream through a DOCSIS 4.0 cable modem is now the new normal. Multigigabit speed is a core pillar of the 10G platform. At this interop, all modems achieved that downstream rate of speed — testament to the work achieved at previous interops.

At the August interop, we looked at upstream speed — that is, the stability of very high-speed traffic on upstream channels. Using a DOCSIS 4.0 ultra-high split, the modems in attendance consistently achieved more than 2 Gbps upstream. Upstream is trickier than the downstream: Whereas downstream is a continuous broadcast from one transmitter (the RPD), upstream is bursty, consisting of multiple modems contributing to the orthogonal frequency-division multiple access (OFDMA) signals that the RPD has to “catch” and accurately demodulate. That upstream burst receiver in the RPD is arguably the most complicated component of the system, especially considering the data rates in play.

So, we’ve arrived at a point where a DOCSIS 4.0 modem is pairing download speeds faster than 9 Gbps with upload speeds faster than 2 Gbps (and with the capability to go even faster). And we’re talking about a single modem. The service group can achieve even more capacity and speed, which means individual modems can also go higher.

Additional DOCSIS 4.0 Cable Modem Operations

Beyond speed, three other aspects of DOCSIS 4.0 technology stood out, offering a look at the maturity of the products at the interop.

PNM

PNM is an important function for cable modems. It’s a proven tool that engineers and technicians use for maintenance, troubleshooting and improvement of the cable plant. More and more, the signals on the plant are OFDM and OFDMA, which provide higher speeds and capacities than traditional quadrature amplitude modulation (QAM) signals.

At this event, we looked at five PNM tests that were run on all the modems. And because DOCSIS 4.0 modems generate more OFDM and OFDMA signals, more data is available. This is a sign of product maturity, responding to these data requests. And the modems have this down. This PNM data will enable the most efficient operation of the coaxial cable network, keeping the data levels at their peak by using the more efficient OFDM and OFDMA signals.

Security

Cable broadband is widely deployed. Hundreds of millions of consumers use DOCSIS technology every day as they live, work, learn and play. DOCSIS 4.0 technology includes strengthened measures to meet the threats that come with online activity. Suffice it to say, new security features are now appearing in products in the labs, and they’re being tested for both functionality and interoperability.

Remote PHY Interoperability

Although modems were the focus, the event also looked at the interoperability between DOCSIS 4.0 cores and RPDs. We branched into more and different configurations, moving beyond “one size fits all” configurations. These products are going to be deployed in many scenarios, and going deeper into these various configurations will ensure flexibility as DOCSIS 4.0 technology moves into the field.

Join Us Next Time

The next DOCSIS 4.0 interop is planned for the week of Nov. 4 at CableLabs’ headquarters in Louisville, Colorado. The event will provide an opportunity for both new suppliers and new products as we all prepare for the new calendar year.

Right around the corner in March 2025 are CableLabs Winter Conference and Smaller Market Conference.

Achieving interoperability in the broadband industry is no small feat. It takes time, patience and attention to detail. Collaboration, problem-solving and flexibility. But, once achieved, interoperability powers innovation and competition within the ecosystem. It enables expanded market opportunities for equipment suppliers and offers operators more options for their subscriber services.

CableLabs provides a neutral testing ground for those suppliers and operators to come together and showcase compatibility across interfaces defined in our DOCSIS 4.0 specifications. Since the launch of the CableLabs DOCSIS 4.0 Cable Modem Certification program in June 2023, we’ve spent many action-packed weeks hosting DOCSIS 4.0 Interop·Labs events. And how far we’ve come in just a year! To recap briefly:

• We’ve achieved a downstream speed of over 9 Gbps through a DOCSIS 4.0 modem — a speed record.
• Testing scenarios have focused on combining DOCSIS 4.0 modems and Remote PHY equipment, as well as DOCSIS 3.1 and DOCSIS 4.0 equipment together, to demonstrate flexibility and backward compatibility.
• We’ve explored network reliability — in particular, DOCSIS 4.0 cable modem proactive network maintenance (PNM) functions in DOCSIS 4.0 cable modem termination systems — and DOCSIS 4.0 security technologies.

DOCSIS 4.0 and DAA Technologies

That momentum is continuing with the success of CableLabs and Kyrio’s most recent event, which combined DOCSIS 4.0 technology and Distributed Access Architecture (DAA). Combining interoperability events for these technologies drives home the importance of compatibility across all system components.

During the June 24–27 event, attendees pushed even deeper into testing the products to examine the intricacies of interoperability in a more nuanced way. Thank you to the participants who helped make the event successful — and once again — helped us unlock a new level of productivity.

The featured exercises involved DOCSIS 4.0 cable modems and DAA equipment. The DAA products included Remote MACPHY devices and Remote PHY equipment such as virtualized cores and Remote PHY Devices (RPDs) that support DOCSIS 4.0 technology. All of these systems came together during the week of exercises to demonstrate multi-supplier interoperability across the DOCSIS ecosystem.

Continued High Level of Participation

Attendance remained high with new suppliers and new products. Operators joined us to observe, interact with the suppliers and talk about their own DOCSIS 4.0 network progress.

Among the suppliers were Casa Systems, CommScope and Harmonic, which brought DOCSIS 4.0 cores to the interop. Remote PHY Devices (RPDs) from Casa Systems, CommScope, DCT-DELTA, Harmonic and Vecima Networks offered a mix of DOCSIS 3.1 and DOCSIS 4.0 technologies. DOCSIS 4.0 cable modems were provided by Arcadyan, Askey, Hitron Technologies, MaxLinear, Sagemcom, Sercomm and Ubee Interactive. Calian attended with its Remote PHY test system, which can be used to verify interoperability between DOCSIS 4.0 cable modems and a DOCSIS 4.0 core. Microchip Technology participated with its clock and timing system. Rohde & Schwarz brought its DOCSIS Signal Analyzer for continued development on DOCSIS 4.0 systems.

Testing scenarios involved using a virtual core from one supplier, and multiple RPDs and DOCSIS 4.0 cable modems from various suppliers. The products were mixed and matched to verify interoperability scenarios and speeds through the system. As before, DOCSIS 3.1 and DOCSIS 4.0 equipment were combined to demonstrate the cross-compatibility of existing and new technology. The test equipment suppliers used these setups to verify their solutions.

This interop had a different vibe than past events but proved that DOCSIS 4.0 modems continue to mature, which is enabling new investigations into the technology.

Sustained Speed

Achieving a rate of 9 Gbps (or more) downstream through a DOCSIS 4.0 cable modem is now the new normal. We’ve now achieved it on multiple modems and multiple cores. (And stay tuned. We’re now expecting DOCSIS 4.0 modems that can exceed speeds of 10 Gbps!)

In the July interop, we began looking at sustained speed — that is, the stability of very high-speed traffic over several hours. One test used two modems on a virtual core and RPD and ran 4 Gbps through each modem (8 Gbps through the core) for three hours, with no loss of data. That was over 5 terabytes (TB) of download per modem in 3 hours!

We also tried to find out how fast a system could download 1 TB. By putting 9.2 Gbps through a modem, we reached the 1 TB download in 18 minutes. That’s up to 50 hours of 4K movie content. More importantly, imagine what these speeds could mean for future services like home health care. This rate of high-speed data transfer will no doubt lead to transformative new products and services for the connected home.

Cable Modem PNM Operations

PNM is an important function for cable modems. These proven tools are used by engineers and technicians for maintenance, troubleshooting and improvement of the cable plant. More and more, the signals on the plant are orthogonal frequency division multiplexing (OFDM) and orthogonal frequency division multiple access (OFDMA), which provide higher speeds and capacities than traditional quadrature amplitude modulation (QAM) signals.

At this interop, we looked at five different PNM tests, specifically getting data from DOCSIS 4.0 cable modems and verifying interoperability with the application programming interfaces (APIs) and with the data generated by the modems. This PNM data will enable the most efficient operation of the coaxial cable network, keeping the data levels at their peak by using the more efficient OFDM and OFDMA signals.

Remote PHY Interoperability

While the modems were the focus, this event also included a deeper look at the interoperability between DOCSIS 4.0 cores and RPDs. These will be new infrastructure for operators and another interface around which interoperability must be proven. To facilitate best-in-class infrastructure for new DOCSIS 4.0 products and services, this interface has to demonstrate flexibility to allow configurations and channel plans that work best for an operator.

At the interop, we spent time purposely trying these new configurations. We sought to ensure the components asking for resources and assigning those resources can communicate and allow for flexibility in configuration that can be used in the new future as DOCSIS 4.0 technology moves into the field.

Join Us at SCTE TechExpo

The next DOCSIS 4.0 interop is planned for the week of Aug. 12 at CableLabs’ headquarters in Louisville, Colorado. The event will provide suppliers an opportunity to sharpen their products — and pitches — for the upcoming SCTE®️ TechExpo conference in Atlanta.

At TechExpo, the must-attend event for the broadband industry, CableLabs will highlight the products and efforts that occur at our Interop·Labs events. Full-access passes are free for CableLabs members. Register now to join us!

CableLabs and Kyrio hosted a combined DOCSIS 4.0 technology and Distributed Access Architecture (DAA) Interop•Labs event April 15–18 at our headquarters in Louisville, Colorado. Combining the interops for these technologies drives home the fact that interoperability across all the system components is a high priority for the industry.

And once again, the operators and suppliers in attendance made this event the most successful interop to date — and the busiest. We even achieved a downstream speed of over 9 Gbps through a DOCSIS 4.0 cable modem!

At this Interop•Labs event, the focus again was on interoperability. The featured exercises involved DOCSIS 4.0 cable modems and Remote PHY equipment, including virtualized cores and Remote PHY Devices (RPDs) that support DOCSIS 4.0 technology. During the week, the mixing and matching of systems and components demonstrated multi-supplier interoperability across the DOCSIS 4.0 ecosystem.

Record-Setting Number of Devices

The event included new suppliers who brought new products, showcasing the depth and breadth of the DOCSIS ecosystem. We set a record for the highest number of DOCSIS 4.0 cable modems and the most RPDs involved in a single interop! Operators also attended to observe demonstrations, interact with suppliers and talk about their own DOCSIS 4.0 technology plans.

As you can probably guess, it was the busiest interop yet. With all the equipment, suppliers and operators on site, it was standing room only in the interop lab — not a bad problem to have. The sheer number of attendees meant we had to move quickly through test scenarios.

Casa Systems, CommScope and Harmonic brought DOCSIS 4.0 cores to the interop, and Calian, Casa Systems, CommScope, DCT-DELTA, Harmonic and Vecima Networks brought RPDs that offered a mix of DOCSIS 3.1 and DOCSIS 4.0 technologies. Arcadyan, Askey, Hitron Technologies, MaxLinear, Sagemcom, Ubee Interactive and Vantiva showcased DOCSIS 4.0 cable modems. Rohde & Schwarz brought its DOCSIS 4.0 test and measurement system, and Microchip Technology participated with its clock and timing system.

Testing scenarios involved using a virtual core from one supplier, an RPD from another supplier and multiple DOCSIS 4.0 modems from various suppliers. The products were mixed and matched to verify interoperability scenarios and speeds through the system. As before, DOCSIS 3.1 and DOCSIS 4.0 equipment were mixed to demonstrate cross-compatibility of existing and new technology. The test equipment suppliers used these setups to verify their solutions.

An Interop•Labs event combined both DOCSIS 4.0 and Distributed Access Architecture technologies in interoperability testing scenarios.

9 Gbps Downstream Speed Unlocked

Multi-vendor interoperability testing is how we achieved a downstream speed of over 9 Gbps. This speed record shows several things: First, the products are nearing feature-complete status and are now being optimized for the speeds that DOCSIS 4.0 technology will bring to market.

Second, DOCSIS 4.0 technology will compete effectively with 10 gigabit passive optical network (PON) solutions that max out at about 8.5 Gbps downstream. DOCSIS 4.0 technology won’t only surpass that speed but will also provide more throughput to the neighborhood than what is possible with 10 gigabit PON. And lastly, these speeds are available over existing coaxial cable already serving tens of millions of customers around the globe.

It's About Network Cohesion

The number of suppliers and products in the industry continues to rise, and CableLabs’ Interop•Labs events bring all of the components of a DOCSIS 4.0 network solution together. With each interop, we’re successfully mixing and matching products from various suppliers and demonstrating interoperability across the interfaces defined in CableLabs’ specification.

In addition, together we’re achieving the multi-gigabit speeds and other advanced capabilities of DOCSIS 4.0 technology such as security, low latency and proactive network maintenance. Other parts of the DOCSIS 4.0 ecosystem are also becoming available, including hybrid fiber coax (HFC) network equipment such as amplifiers, taps and passives.

It’s exciting work, and we’re always looking forward to the new developments and takeaways that come out of events like these. Catch up on past interops and click the button below to stay up to date on future DOCSIS technology interop events.

CableLabs and Kyrio hosted a combined DOCSIS® 4.0 technology and Distributed Access Architecture (DAA) Interop•Labs event February 12–15 at our headquarters in Louisville, Colorado. This was the first combined interop between CableLabs and its subsidiary, and the involved suppliers and operators made it a success.

At this Interop•Labs event, the exercises included both DOCSIS 4.0 cable modems and Remote PHY equipment, including virtualized cores and Remote PHY Devices (RPDs) that support DOCSIS 4.0 technology. During the week, mixing and matching of systems and components demonstrated multi-supplier interoperability across the DOCSIS 4.0 ecosystem.

Interop Takeaways

Casa Systems, CommScope and Harmonic brought DOCSIS 4.0 cores to the interop, and Casa Systems, Cisco, CommScope, DCT-DELTA, Harmonic, Teleste and Vecima brought RPDs that offered a mix of DOCSIS 3.1 and DOCSIS 4.0 technologies. Arcadyan, MaxLinear and Ubee Interactive showcased DOCSIS 4.0 modems. Rohde & Schwarz also participated with its DOCSIS 4.0 test and measurement system. Operators attended to observe the interop, interact with the suppliers and talk about their DOCSIS 4.0 technology plans.

The focus of the interop was interoperability across the ecosystem. A common test scenario at the event involved a virtual core from supplier A, an RPD from supplier B and a DOCSIS 4.0 modem from supplier C, all connected and operating according to specifications. The products were mixed and matched to investigate interoperability scenarios, with suppliers pitching in to analyze the results. To demonstrate extra flexibility for cable operators, suppliers mixed DOCSIS 3.1 and DOCSIS 4.0 equipment because the specifications are written for cross-compatibility.

Above, engineers collaborate during the first combined DOCSIS 4.0 Interop•Labs event hosted by CableLabs and its subsidiary, Kyrio.

Interestingly, the interop illustrated how the traditional cable modem termination system (CMTS) has been disrupted by virtualization. Provided by one supplier, the CMTS used to be one box that did it all. Now, the software components have been abstracted into a virtual core that runs on servers in our data center, while the physical-layer components have migrated to the fiber node. This virtual architecture provides both better scalability and improved flexibility for the software, as well as better physical-layer performance on the coaxial cable. And in between, the fiber-optic cable uses much more scalable digital Ethernet connections.

The interop also demonstrated that the core and fiber node components can come from different suppliers because that interface is described in the CableLabs Remote PHY specifications. Looking at interoperability from all angles benefits all stakeholders. Interoperability enables a larger market in which suppliers can compete, which leads to varying competitive strategies and healthier ecosystems. Interoperability gives operators the confidence to plan large installations and the certainty that the equipment they put in the field this year will work for years to come.

Remote PHY interoperability events began in 2017 with DOCSIS 3.1 technology, so these solutions have been in the field for years and have matured. This interop shows that the migration to DOCSIS 4.0 technology is both very far along and proceeding smoothly — and that the supplier community has embraced interoperability among system components.

It's About Network Cohesion

The integration and optimization of the DOCSIS 4.0 ecosystem is underway. The goal has moved beyond simply booting DOCSIS 4.0 modems. Rather, we’re putting together all the parts, mixing and matching from different suppliers, demonstrating interoperability across the interfaces defined in CableLabs specification and achieving the multi-gigabit speeds and other advanced capabilities of DOCSIS 4.0 technology such as security, low latency and proactive network maintenance.

Other parts of the DOCSIS 4.0 ecosystem are also becoming available, including hybrid fiber coax (HFC) network equipment such as amplifiers, taps and passives.

To learn more about this exciting evolution, join us next month at CableLabs Winter Conference. This exclusive event for CableLabs members and the NDA vendor community will explore DOCSIS technology in two powerful sessions: “Unleashing the Full Potential of the DOCSIS 4.0 Network” and “A Vendor Perspective on DOCSIS 4.0 Technology Implementation.” You’ll hear from industry leaders about effective strategies, opportunities and benefits of the DOCSIS 4.0 network. Join us!