Operators will have options for Distributed Access Architectures

Transcription

1 SPECIAL REPORT Operators will have options for Distributed Access Architectures By Stephen Hardy SPONSORED BY Reprinted with revisions to format from BTR. Copyright 2018 by PennWell Corporation

2 SPECIAL REPORT Operators will have options for Distributed Access Architectures Cable operators will have a wealth of technology options at their disposal as they make their plans to evolve toward Distributed Access Architectures. The move to Distributed Access Architectures (DAA) promises a variety of benefits. And what operator wouldn t be interested in reduced power, cooling, and space requirements in their headend and hubs, better transmission performance (an increase in MER of 6 to 9 db, say some industry sources), and a simplified network architecture? The question operators face is how to implement DAA. Based on a look at the DAA technology landscape, it appears cable MSOs will have plenty of options within the next few years that will enable them to customize their strategies to the requirements of individual serving areas. The benefits are remote DAA, as the name implies, sees functions that normally reside in the headend or hub distributed into the network, closer to the user, in an intelligent node. Removing functions into the network reduces the amount of hardware the headend or hub must house, Cable operators will have a wealth of technology options at their disposal as they make their plans to evolve toward Distributed Access Architectures. thus leading to the power, space, and cooling requirement reductions. The remaining headend or hub equipment communicates with the intelligent node via a 10 Gigabit Ethernet fiber link, using previously analog transmission spectrum converted to digital. The switch to digital transmission enables the increase in the transmission performance over the coax connection to the customer. 2 BTR Special Report: Distributed Access Architectures SPONSORED BY

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4 Remote MACPHY should dovetail well with the evolution toward cloud-based network approaches. The question is what function or functions the operator would like to migrate to the remote node. CableLabs has begun work on a pair of DAA approaches within its Distributed CCAP Architecture initiative (a subset of its overall DAA activities). Remote PHY is the first architecture it took up, with specification work nearly complete. Here the PHY functions such as the modulation of DOCSIS and video signals move from the CCAP platform into a Remote PHY Device (RPD) in the intelligent node. The CCAP-related functions that remain in place reside in a CCAP-core, which performs Ethernet conversion, tunneling and routing for DOCSIS frame transmission as well as DOCSIS MAC functions. The CCAP-core can be paired with off-the-shelf routers and switches in a significantly simplified architecture. With Remote PHY specifications nearly completed, systems vendors have begun to unveil Remote PHY hardware. CableLabs has conducted 11 interoperability events that have helped operators evaluate the technology s readiness for deployment. ARRIS CTO Network Solutions Tom Cloonan, during an SCTE ISBE LiveLearning Webinars for Professionals event in March 2018, predicted that deployments of specification-compliant RPDs should begin this year. 4 BTR Special Report: Distributed Access Architectures SPONSORED BY

5 Meanwhile, this past December, CableLabs turned its attention to the second major DAA approach, Remote MACPHY. This strategy sees the DOCSIS MAC function also moved into the intelligent node. Removing the MAC function from the headend or hub also removes the need for a CCAP-core, leaving only routing, switching, and controller functions with the controller functions cloud-ready. CableLabs plans to leverage as much of its Remote PHY work as possible, reported Jon Schnoor, lead engineer at the organization, during the same webcast. The specification makers plan to create a Remote MAC Device (RMD) that would incorporate the RPD. They also envision a Remote MAC Core (RMC) that could remain structurally separated from the RPD; this would remove the MAC function from the headend/hub but still enable the MAC function to be shared among multiple RPDs. CableLabs also plans to create a virtual MAC core for SDN-enabled environments. For headend and hub requirements, specifications will cover a MAC Manager for the network s management plane, an SDN Controller for Layer 2 and 3 control plane needs and a DOCSIS Controller for the DOCSIS control plane. While Remote MACPHY promises the most streamlined approach to serving user needs, the necessary hardware and software isn t likely to be ready for some time. Schnoor described Remote MACPHY specification development as a lot of work, while Cloonan predicted RMDs won t see deployment until around 2020, and RMCs with subtending RPDs until Thus, operators can choose to deploy Remote PHY in the near future if their DAA requirements are acute, wait a bit to take the full plunge into Remote MACPHY or anticipate that they can start with Remote PHY and evolve to Remote MACPHY down the road. Other considerations However, this choice won t be made in a vacuum. For example, while operators are using a 10 Gigabit Ethernet fiber link between the headend/hub and intelligent node, they may want to use that fiber cable to support other Ethernet-enabled services. Business services as well as 4G/5G centralized radio access network (C-RAN) and small cell fronthaul/backhaul traffic also could use the same fiber. Optical transport systems vendors see Distributed Access Architectures as a new market opportunity. Such converged network potential has attracted the attention of optical transport systems vendors, who believe they could have a role to play in supporting DAA alongside other forms of Ethernet traffic. Platforms that combine packet switching with optical transport would fit well within a converged network that enables DAA, they are telling cable operators. 5 BTR Special Report: Distributed Access Architectures SPONSORED BY

6 Meanwhile, fiber to the premises (FTTP) equipment suppliers continue to push greater use of all-fiber architectures. The connection from the intelligent node to the customer doesn t have to take place over coax, meaning there could be a demand for remote optical line terminals (R-OLTs) within the DAA framework. The FTTP platform community has already begun to tout such arrangements, pointing out that their SDN-friendly offerings would pave the way to either Remote PHY or Remote MACPHY implementations. And, of course, there s nothing that prevents DAA networks from supporting Full Duplex DOCSIS or, if and when it comes to pass, extended spectrum DOCSIS technology. In short, operators likely will examine DAA from a variety of angles. Asked during the webcast which of the many options would prove most popular among operators, Cloonan related that he had spoken to three operators shortly before the webcast, and all three were planning different DAA pathways, each for valid reasons. It seems that operators will not only have several options from which to choose, but that each approach will have its adherents. And there s nothing that says an operator must choose a single approach. The evolution of DAA deployments promises to be multifaceted, perhaps within a given operator but certainly across the community at large. Stephen Hardy is editorial director of Broadband Technology Report. Learn the Basics of Distributed Access Architectures You can now view on-demand the March 2018 SCTE ISBE LiveLearning Webinars for Professionals webcast, produced by BTR, Distributed Access Architectures. This webinar defines the various Distributed Access Architecture options, describes the work now underway on such architectures within CableLabs, offers predictions for technology evolution, and covers the ramifications for network testing. Register for the webinar and view it now! 6 BTR Special Report: Distributed Access Architectures SPONSORED BY

7 Description ARRIS is a global leader in entertainment, communications and networking technology. Our innovations combine hardware, software and services to enable advanced video experiences and constant connectivity across a variety of environments for service providers, commercial verticals, small enterprises, and the billions of people they serve. Our three core business units: Customer Premises Equipment (CPE), featuring access devices such as video settops and gateways, and broadband modems, gateways, and routers Network & Cloud, combining broadband and video infrastructure with cloudbased software solutions Enterprise Networks, incorporating the newly acquired Ruckus Wireless and ICX Switch business and focusing on wireless and wired connectivity Together, we are powering the digital world. MORE RESOURCES: DISTRIBUTED ACCESS ARCHITECTURE (DAA) SOLUTION NETWORK TRANSFORMATION PRACTICE ADDRESSING CAPACITY AND PERFORMANCE CHALLENGES WITH FIBER DEEP ARCHITERCTURE AND THE ARRIS POD METHODOLOGY NETWORK MIGRATION STRATEGIES FOR THE ERA OF DAA, DOCSIS@3.1 AND FULL DUPLEX DOCSIS A COMPARISON OF CENTRALIZED VS. DISTRIBUTED ACCESS ARCHTITECTURES FOR PONY 7 BTR Special Report: Distributed Access Architectures SPONSORED BY

8 DISTRIBUTED ACCESS ARCHITECTURES: A NETWORK EVOLUTION PATH TO EXTEND VIDEO AND DATA SERVICES

9 Distributed Access Architectures: A Network Evolution Path to Extend Video and Data Services Bandwidth usage continues to grow year after year, mainly driven by consumer video consumption. Advanced applications and services have given subscribers new and easy ways to share experiences and stay connected using the devices of their choice. But keeping up with today s capacity demands can be a challenge for Service Providers who are trying to leverage aging technology and overflowing head-ends. The key for Service Providers is to add capacity to their hybrid fiber-coaxial (HFC) networks in a cost-efficient manner, while maintaining the highest quality of service for subscribers. As such, Service Providers need to establish a network evolution path for enhancing head-end bandwidth capacity that utilizes their integrated CCAP platforms but adds the capability to scale services as they grow. This requires an understanding of the practical constraints in their network operations including physical space, power consumption and cooling in head-end locations. There is more than one path to network evolution While some Service Providers will likely be able to support new video and HSD services using traditional head-end-based integrated CCAP (I-CCAP) platforms, others may be considering alternate architectural approaches. There may be other constraints, such as available power and rack-space that prohibit adding more I-CCAP hardware. However, alternate approaches such as Distributed Access Architecture (DAA) or Fiber to the Home (FTTH) help Service Providers add the capacity they need using the footprint and some of the resources they already have. DAA builds on the existing HFC infrastructure, migrating from analog signaling over fiber to using digital signaling and extending the reach of the fiber closer to the subscriber. This approach decentralizes the infrastructure towards a software-defined network that virtualizes key head-end and network functions. It also extends the digital portion of the head-end or hub domain out to the fiber optic node and places the digital to RF interface at the optical-coax boundary within the node. Replacing the analog optics from the head-end with a digital optics and a fiber Ethernet link increases the available bandwidth and improves fiber efficiencies with regard to both wavelengths and distance. In doing so, Service Providers can enhance directional alignment with network function virtualization (NFV), transition to software-defined networks and provide an evolution path to the FTTx systems of the future. 1 WEB BLOG

10 For Service Providers, the resources to run additional fiber, implement node splits and upgrade head-end facilities can require significant investment. But with DAA, these investments can be made gradually as part of normal plant servicing or demand driven upgrades with minimal disruption to existing services. Additional benefits of DAA include: Network efficiency Increased network capacity and simpler outside plant maintenance Node evolution with Remote PHY, Remote MAC-PHY and Remote 10G EPON OLT Better end-of-line signal quality, higher modulation rates, higher bit-rates Better spectral efficiency, more wavelengths per fiber Operational and capital expenditure benefits Reduced head-end power, space and cooling requirements Hub consolidation Adding QAMs without changing the RF combining network IP convergence Extended IP network to the node Alignment with FTTx build-out Ability to leverage standards-based interconnectivity and economies of scale Another fork in the road There are several approaches to DAA being proposed for use by Service Providers, and each has its own set of advantages and disadvantages. Let s take a brief look at three of the most common architectures. Distributed Access Architecture - DAA NODE/GATEWAY PASSIVES ACTIVES CPE I-CCAP CENTRALIZED ACCESS ARCHITECTURE - I-CAPP HEAD-END OPTICS HYBRID FIBER COAX HFC NODE CCAP MAC CORE FIBER SWITCHING LEAF SPINE DIGITAL OPTICS (OPTICAL) ETHERNET / G.709 / PON) DIGITAL OPTICS R-PHY NODE PHY DATA CENTER FIBER SWITCHING LEAF SPINE DIGITAL OPTICS (OPTICAL) ETHERNET / G.709 / PON) DIGITAL OPTICS R-MAC PHY NODE PHY 2 WEB BLOG

11 Remote PHY (R-PHY) This approach separates the PHY (upstream and downstream RF) from the head-end and places the full PHY layer at the fiber node. It s slightly disruptive, as it requires pieces of head-end equipment to be modified. However, Remote PHY helps with the nonlinear optical noise problem by using digital optics instead of analog, it addresses the head-end power and rack-space challenge and offers investment protection because it allows the re-use of head-end-based CCAPs. Remote MAC/PHY (R-MACPHY) This approach places all of the CMTS, Edge QAM and CCAP functions into the fiber node and only requires switches or routers to remain in the head-end, so it is disruptive, requiring replacement of head-end equipment and parts of the node platforms. R-MACPHY also helps with the nonlinear optical noise problem and maximizes power and rack-space savings within the head-end. Remote PHY with virtual core (vcore) An extension of the R-PHY approach, the MAC core functionality is virtualized and run on commercial off-the-shelf compute platforms. This architecture typically requires more head-end space than dedicated hardware, but by decoupling the hardware from the software functionality, each can be updated independently. The virtual platform can be shared with other applications and can be easily scaled up and down to meet demand. This allows the hardware to be scaled back when not needed for added power savings. Our framework for network evolution The ARRIS Access Network Evolution Framework allows Service Providers to start with common core elements in each of the major system areas, such as video delivery, broadband data services and the access infrastructure. With a flexible approach, Service Providers can evolve their network infrastructure at a pace that aligns with service demands, and apply the necessary resources that will ensure quality of service and experience for subscribers into the future. For more information, please visit arris.com. 3 WEB BLOG