understanding the converged cable access platform1

CCAP 101: Guide to Understanding the Converged Cable Access PlatformFEBRUARY 2012

WHITE PAPER CCAP 101: GUIDE TO UNDERSTANDING THE CONVERGED CABLE ACCESS PLATFORM

Table of Contents

Abstract .......................................................................................... 3

CCAP Benefits ................................................................................ 4

Architectural Flexibility ................................................................. 5

Further Considerations for Deployment ...................................... 6

Conclusion: CCAP and the Shift to IP ............................................................... 7

WHITE PAPER CCAP 101: GUIDE TO UNDERSTANDING THE CONVERGED CABLE ACCESS PLATFORM 3

With consumers demanding more content on more screens, cable operators are seeking a cost-effective strategy for migrating from conventional MPEG-based video delivery to IP video transport. The Converged Cable Access Platform (CCAP) was designed with this goal in mind, and proposes to combine data and video delivery as a first step on the migration path. While cable operators today implement data and video QAMs on separately managed and controlled platforms, CCAP provides a blueprint for combining CMTS and edge QAM functionality in one hardware solution. CCAP promises significant improvements in QAM channel density, and the flexibility for cable operators to expand data and video services while also planning for a future world of all-IP delivery.

Abstract


Cost containment is the biggest impetus behind CCAP. As part of combining data and video delivery, CCAP is focused on creating denser hardware to support a larger number of QAM channels. The more QAM channels are supported, the further operators’ cost per channel falls. These costs are already plummeting because of huge channel demand, but they’re not falling as fast as cable operators would like. Growth in demand for DOCSIS® QAMs to support greater Internet traffic, and narrowcast video QAMs to support more video-on-demand streams, is putting a strain on the existing cable access network. The resulting need for infrastructure upgrades places a strain on both capital and operations budgets.

Today, the cost per downstream channel is decreasing at a rate that is roughly equivalent to the continued rate of increase in downstream traffic. Downstream QAM costs are already about an eighth of what they were four years ago. With CCAP however, manufacturers can push those costs down even further. CCAP hardware is predicted to offer between four and six times the density of a typical CMTS platform, providing downstream capacity of more than 150 Gbps.

In addition to cost per bit, the other major benefit to increased density is the ability to save rack space in the cable headend. With the much higher density available in a CCAP platform, roughly half the number of chassis will be needed to serve the same subscriber base as compared to existing CMTS deployments. The CCAP chassis will also include support for video on demand and switched digital video services, negating the need for further specialized equipment and adding to the potential space savings. Broadcast QAM channels may even appear in a CCAP platform in the near future.

CCAP Benefits

Figure 1: CCAP offers many important benefits

Figure 2: CCAP Architectural Flexibility


Significant improvements in power consumption and cooling costs per channel mark another huge benefit to increased channel density. According to a CableLabs technical review, operators can expect power savings of more than 50 percent, with decreases in power consumption also leading to a reduction in the amount of heat generated. The combined savings are good for both operator budgets and the environment, and should help reverse a trend whereby operators continue to add an increasing number of boxes to the traditional headend stack.

Other benefits to the CCAP model include QAM flexibility and a transport-agnostic network architecture. CCAP hardware will support QAM channels for both DOCSIS services and broadcast and narrowcast MPEG/DVB video services. It will also offer a simplified configuration option so that operators can adjust QAM channel allocations at will, shifting channels from DOCSIS delivery to narrowcast MPEG service delivery and back again as needed.

By enabling multiple types of access network connections, CCAP will support traditional HFC networks, as well as commercial EPON deployments. Further access network technologies are also expected to be supported. The goal is to make CCAP compatible regardless of how cable networks evolve in the future.

Architectural Flexibility

Even as many operators are now investigating future CCAP deployments, there are several issues impacting the potential timing of any migration. Most notably, increased demand for narrowcast QAMs has propelled a new generation of edge QAMs to market that deliver narrowcast services more efficiently and cost effectively. While operators may ultimately want to merge data and video operations, the advantages of dropping higher-density edge QAMs into the network to increase capacity today are compelling.


Figure 3: CCAP combines the capabilities of an edge QAM and a CMTS into a single platform, which may be deployed as integrated or modular, similar to M-CMTS

The result of competing QAM priorities is that two potential roadmaps for CCAP implementation have emerged. There is an integrated approach for CCAP deployment, and a distributed CCAP approach. In an integrated system, all CCAP components – including the packet processing and management module, as well as various line cards, including downstream and upstream HFC modules and an EPON module – are located within a single chassis. This allows the operator to manage the chassis as a single device, and, in some cases, to reduce the number of spare modules required. There is a downside, however. An integrated architecture allows less flexibility for incremental CCAP deployments.

A distributed CCAP deployment still paves the way for an integrated CCAP architecture, but it also provides flexibility in the migration process. In this model, a high-density edge QAM can be deployed today, but with unused QAM channels set aside for delivering DOCSIS traffic in the future. As long as the edge QAM can be configured later for both video and data traffic delivered from a CCAP core chassis, operators can take advantage of the high-density video hardware now, and still use it as part of an eventual CCAP rollout.

Further Considerations for Deployment

While demand for narrowcast QAMs is one variable impacting CCAP deployment strategies, DOCSIS channel utilization is an equally important consideration factor. Where timing is concerned, there is a key inflection point when the economics of CCAP overtake those of a traditional CMTS. When operators start looking to supply more than eight bonded or non-bonded downstream DOCSIS channels per serving group or fiber node, a CCAP platform becomes the more efficient architecture, especially from an OPEX perspective. For many if not all MSOs, this means the migration to CCAP will likely take place one headend at a time. As a particular region hits new capacity requirements, an operator can make the transition from CMTS to CCAP. This approach spreads out the necessary infrastructure investment costs and creates a roadmap for incremental network upgrades.


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Conclusion: CCAP and the Shift to IP

For some cable operators, CCAP will be the next step on the road to all-IP delivery. However, there are many paths for moving from today’s systems to CCAP and beyond. Cable providers need several strategies to preserve existing investments, meet new subscriber demands, and, ultimately, converge data and video delivery for greater resource efficiency and service growth. The way ahead will be defined by continued standards development and market trends, as well as individual cable operator budgets and priorities.

About Motorola MobilityMotorola Mobility, Inc. (NYSE: MMI) fuses innovative technology with human insights to create experiences that simplify, connect and enrich people’s lives. Our portfolio includes converged mobile devices such as smartphones and tablets; wireless accessories; end-to-end video and data delivery; and management solutions, including set-tops and data-access devices. For more information visit www.motorola.com/Video-Solutions/US-EN/Home.

Meanwhile, in the upstream, operators need to consider not only channel density and channel bonding, but also how to expand spectrum utilization within each channel to achieve higher throughput overall. With predicted upstream bandwidth demand increasing 300-400 percent in the next five to seven years, the need for higher upstream capacity will soon become critical. Operators need ways to make better use of each upstream channel, particularly as serving group sizes expand from two to four upstream channels today, to between eight and twelve upstream channels in the future.

Advanced DOCSIS 3.0 Synchronous Code Division Multiple Access (S-CDMA) technology as well as 256 QAM modulation are requirements for greater upstream utilization and can help fulfill the promise of CCAP for upstream traffic. Advanced S-CDMA expands upstream spectrum availability by cancelling most ingress and impulse-related issues that occur at low-spectrum frequencies. It allows operators to place upstream channels anywhere in the 5-85 MHz frequency band. In addition, 256 QAM modulation provides a 33 percent increase in effective throughput compared with 64 QAM. With S-CDMA and 256 QAM, operators can reach throughputs in excess of 100 Mbps with only three bonded channels. Paired with the density of proposed CCAP hardware, the technology opens up new thresholds for upstream bandwidth delivery.

understanding the converged cable access platform1

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