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Optimizing cable networks to keep pace with the consumer demand for more bandwidth and faster speeds is nothing new. What has changed—and what will make expanding the network more challenging than it’s ever been—is the myriad of current and emerging options to grow the network and optimize headend support. Choosing the “right” path is a crucial business decision facing MSOs both today and in the future.
As broadband networks continue to evolve, MSOs are also facing an evolution in the modular technology that drives content delivery through their networks and into the consumer’s home. Distributed Access Architectures (DAAs), for example, revolutionize traditional headend operation by taking varying amounts of CMTS functionality out of the headend and into an optical node at the edge of the network.
Similarly, next-generation passive optical networks (PON) deployment can utilize a node-based optical line terminal (OLT) module to migrate or supplement an existing DOCSIS HFC network, while maintaining DOCSIS provisioning compatibility with 10G EPON or utilizing XGS-PON with its SDN-based Domain Management for network provisioning and telemetry gathering. Both technologies provide a seamless, efficient path for driving fiber deeper into the network—in both urban and rural Brownfield and Greenfield applications—while reducing the energy, maintenance and operational requirements of traditional headend operation. The question is: where to begin?
Market Drivers: Familiar Faces
The market drivers behind this demand for more capacity and speed are familiar, and so is the common solution to them: the expansion of the network spectrum, especially in the upstream path. We see this theme in such trends as the normalization of virtual and hybrid workplaces in the wake of the COVID-19 pandemic and the concomitant rise in video conferencing. And we see it in the home: through virtual doctor visits, 4K video streaming and gaming and the increasingly ubiquitous deployment of IP-based smart home devices placing additional demands on network reliability, capacity and delivery speeds.
The stresses these devices and services place on network capacity, network traffic and minimum network speeds are significant. Work from home trends, for example, have resulted in roughly 25% growth in residential upstream and 20% growth in residential downstream bandwidth usage during peak hours over the past couple of years. 4K video streaming requires around 50 Mbps per stream for maximum image quality—and that number increases as more screens and/or smart devices are introduced into the mix. Similarly, the typical 4K gaming stream runs at 60 frames per second, which translates into a minimum required internet speed of 100 Mbps. And smart home devices are becoming more commonplace as well, with just the smart thermostat market alone expected to have a CAGR of 17.1% through 2028.
With all these market drivers in play for 2023 and beyond, a mix-and-match approach to network development is prudent and will allow traditional and cutting-edge network and headend innovations to blend seamlessly, simplifying the process of expanding bandwidth and increasing speeds.
Evolving the Network: Optimizing Current Technology
Networks are evolving in two ways. The first, and most immediate, is network optimization for DOCSIS 3.1 operation. This is accomplished by updating active network components, such as amplifiers and nodes, for mid- or high-split operation. In high-split operation, an additional portion of the spectrum is allocated to the upstream for speeds of approximately 1 Gbps— a fivefold increase from the sub-split speeds achieved from 5-42 MHz spectrum. Looking toward the future, however, MSOs are beginning to lay the groundwork for DOCSIS 4.0 operation. DOCSIS 4.0 greatly expands the available spectrum and can achieve maximum speeds in excess of 5 Gbps. This increased spectrum will allow MSOs to eventually offer multi-gigabit symmetrical services over their standard HFC network.
The approach to DOCSIS 4.0 operation is one of scale —which is to say that MSOs have not one, but two options for DOCSIS 4.0: Full Duplex DOCSIS (FDX) and Extended Spectrum DOCSIS (ESD), which is also known as Frequency Division Duplex (FDD) technology. ESD/FDD extends the downstream spectrum to 1.8 GHz, while FDX operates in the 1.2 GHz downstream spectrum with simultaneous downstream and upstream transmission in a portion of the same spectral band. Both approaches support an upstream frequency of up to 684 MHz. These approaches are not mutually exclusive: an MSO could plan for ESD upgrades in one part of their system while planning for an FDX upgrade in another, depending on their service requirements. A clear advantage to this mix-and-match approach is its flexibility, especially with aging plants. MSOs have a unique opportunity to pick and choose the technologies that best suit their current and future operational and architectural network requirements, while also leveraging a significant portion of their existing network architecture to support these improvements.
Remaking the Network: The Revolutionary Approach
DAA and PON technologies can be considered revolutionary in the way they leverage existing HFC architecture to remake and redeploy the network edge. The technologies use a modular, node-based approach, are easily scalable, and enable MSOs to prepare for the transition from traditional HFC networks to a virtualized, potentially all-fiber network architecture. And both solutions can leverage CommScope’s extensive base of currently deployed nodes to allow MSOs to upgrade their networks at their own pace while minimizing capital expenditures.
DAA decentralizes and virtualizes headend and network delivery, enabling MSOs to replace analog laser technology with digital optics. DAA provides better spectral efficiencies with deeper fiber deployments and expands the number of wavelengths supported on each fiber. It also enhances support for IP video.
At the edge of the network, DAA uses one of two approaches: Remote PHY (R-PHY), which moves DOCSIS signal generation out of the headend and into a module in the access node; or Remote MACPHY (R-MACPHY), which does the same for DOCSIS signal generation and processing. CommScope has a rich portfolio of both Remote PHY Devices (RPDs) and Remote MACPHY Devices (RMDs), as well as software upgradable RxDs that can support either R-PHY or R-MACPHY operation. There are pros and cons to either approach—primarily centered around cost of deployment and the extent to which they support virtualization—but these are mitigated by the operational flexibility they provide MSOs.
As with network optimization, there is no one-size-fits-all approach to DAA; rather, MSOs can choose the approach that best supports their specific network architectures, requirements and goals. CommScope has been supporting operators in making these decisions and is actively supporting significant deployments of both architectures. Some R-PHY deployments, for example, utilize a virtual CCAP Core, while others utilize a physical CCAP Core. The latter involves an Integrated Converged Cable Access Platform (I-CCAP)—such as the CommScope E6000® Converged Edge Router (CER)—configured as a CCAP Core. The physical CCAP Core approach enables operators to extend their existing CCAP deployments utilizing equipment that has already been integrated into their back-office systems, for an easy migration or extension of services to R-PHY.
Next-generation PON technology can also be a game changer for select business customers, high-bandwidth residential subscribers, MDUs, rural deployments and other market opportunities. PON OLTs can either be deployed in a headend/hub chassis or remotely in a CommScope optical node. Next-generation PON deployments use a cloud-to-edge approach that gives a system operator the opportunity to choose between an EPON network—the fastest route to PON, which requires minimal changes to headend and CPE architecture—or a GPON network, which maximizes network performance and restructures back-office technology.
Network monitoring solutions—such as CommScope’s ServeAssure NXT suite—are also evolving in parallel with DAA and PON technologies. Advanced network monitoring in either of these environments will allow MSOs to better manage the increased complexities of their evolving networks—including advanced analytics on potential bandwidth and capacity risks to ensure maximum network performance and identify key areas in the network that may require upgrades. This feature is especially useful for allocating resources intelligently and efficiently.
Evolving & Virtualizing the Cable Headend
Many of the bandwidth-increasing activities that operators are exploring—increasing upstream spectrum to mid-split (85 MHz) or high split (204 MHz) and the downstream spectrum to 1.2 GHz—can be achieved even with existing I-CCAPs. In addition, operators are also using these platforms as the CCAP Core for Remote PHY operation to provide a seamless evolution and transition to the R-PHY DAA.
An additional emerging trend in cable networking is the virtualization of the CCAP operation. Virtual CCAP operation splits and moves access network functions from specialized CMTS or CCAP hardware to software running on commercial, off-the-shelf (COTS) servers. Virtual CCAP is scalable, elastic, agile, and versatile. Virtual CCAP infrastructure combines Network Function Virtualization (NFV) and Software-Defined Networking (SDN) to bypass the “service silo” model and lower capital expenditures. A virtual CCAP infrastructure fully optimizes DAA operation by supporting the independent scaling and modification of new and current RPD service groups via cloud-based core management, control plane, and data plane functions.
The CommScope Virtual CCAP solution is comprised of a Virtual DOCSIS Core, Domain Manager, and Video Unified Edge (VUE). Domain Manager, which supports open-standards SDN-based interfaces, quickly and efficiently configures, manages and monitors devices and provides MSOs with a means of automating the provisioning of new cores and nodes across their networks. VUE, a suite of modular software functions, can be used to virtualize (and thus simplify) an MSO’s legacy QAM video network. VUE is a video auxiliary core in CommScope’s dual-core DAA architecture that supports video data and control planes. VUE is also a key component in CommScope’s next-generation ad insertion system (NGI), which unifies ad insertion for set-top box and IP clients, eliminating the need to maintain two separate ad insertion systems.
The Way Forward
The plethora of new and evolving technologies can seem daunting. There are many paths available to optimize networks for DOCSIS 3.1 and beyond, transition from HFC to all-fiber network architectures, and virtualize the headend. CommScope is uniquely positioned to guide MSOs toward the solutions that best fit their business goals. That’s because we’re the one company in the cable industry that has a full, end-to-end suite of products and solutions for emerging and future industry trends. With our fully stocked toolbox of reliable, proven solutions, coupled with our decades of experience in helping MSOs evolve and optimize their networks, CommScope is the partner MSOs can rely on to guide them through the next era of network evolution and beyond.
 Zoran Maricevic, “All Aboard the Path to 10G.” On Topic: On the Path to 10G. Broadband Technology Report, 14 December 2022. www.broadbandtechreport.com.
 John Ulm, Zoran Maricevic, and Ram Ranganathan, “Broadband Capacity Growth Models: Will the end of Exponential Growth Eliminate the Need for DOCSIS 4.0,” SCTE Cable-Tec 2022, SCTE. The paper points out that future demand for bandwidth is subject to a “cone of uncertainty” and may grow at a greater or lesser pace than we’ve seen recently.
 Fortune Business Insights, U.S. Smart Thermostat Market Size, Share & COVID-19 Impact Analysis, By Product (Connected, Standalone, and Learning), By Technology (Wired and Wireless), By Application (Residential, Commercial, and Industrial) U.S. Forecast, 2021-2028.