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Engineering-Wise - Upping the Capacity Ante

Fri, 09/30/2011 - 8:10pm
Daniel Howard, Senior Vice President of Engineering and CTO of SCTE

Customers demand capacity increases.

The need to manage and add capacity to cable networks is almost as old as the networks themselves. Whether it has been regular additions of downstream RF bandwidth, digital video compression, or increases in upstream capacity via higher-order QAM and S-CDMA, our networks have continually evolved to allow more capacity. And with deep fiber, RFoG and carrier Ethernet, substantial capacity increases to the home and business are now possible.

Daniel HowardCapacity increases are needed because customers demand them, competition drives them and new revenue is available. Historical data shows 45 percent CAGR growth in bandwidth demand is the general rule. And technological innovations such as cheaper laptops, tablets and smartphones have created yet another wave of increased capacity needs. Changes in consumer behavior that lead to an everything-on-demand type consumption have demonstrated that the time is right for such long-awaited services as interactivity and advanced advertising. Multi-platform viewing has accelerated the evolution toward IP video and has required management of over-the-top (OTT) offerings in a way that makes capacity planning and management particularly challenging. DOCSIS 3.0 rollouts are enabling higher-margin business services customers over HFC and IP video, but 3.0 provides only a modest capacity increase from statistical multiplexing.

As always, cable engineers and technologists have accommodated this challenging bouquet of new services in a cost-effective manner that strategically increases access network bandwidth while leveraging the capabilities of existing networks and preserving the quality of experience for current subscribers. This strategy of “capacity management” – the subject of a day-long symposium just prior to SCTE Cable-Tec Expo this November – takes a holistic view of network architecture and operations.

With that in mind, and keeping in mind that all capacity management situations are not equal, the following questions are germane to the network planning process:

• Technology drivers and traffic models – What performance considerations and advanced technology drivers can impact network design? What traffic modeling approaches are available to engineers? When evaluating such issues as “capacity vs. network availability and QoS,” or “delay vs. load analysis,” which factors take priority?

• Network architecture and capacity planning – What architectural options are available? When segmenting the network into “homes per node” and “nodes per transmitter,” which metrics matter most? How does segmentation affect performance, monitoring and maintenance?

• Managing DOCSIS capacity – How will DOCSIS 3.0 affect network planning? What will be the implications of bonded channels and IP video on network segmentation? How can the industry best accommodate IP-based apps on untethered devices? How should exponential growth and peak traffic flows be factored in? And at a deeper level, what about the potential impact of DOCSIS upstream and downstream configurations on network performance and capacity?

• Video services – As video and advertising continue to morph to an environment of multiple sources, multiple destinations, and increased interactivity and personalization, how will they impact network performance and quality of service? What blocking and capacity issues will arise, and what are potential solutions? How do we ensure continued optimal video quality?

• Monitoring and maintenance – How will changes in the network architecture affect the ability of cable operators to proactively see, evaluate and repair potential disruptions? What kinds of tools will be needed to monitor network health and capacity? How should engineers evaluate operational considerations, such as the need to efficiently use spectrum vs. the need to tightly maintain networks to ensure readiness?

• Service planning – What services are anticipated to be offered, and what demands will they place on the HFC spectrum? What are the implications of high-revenue opportunities such as business services on spectrum planning and management? How can we flexibly plan today for services well over the visionary horizon?

• Trends – What patterns are emerging in other markets, and even in other industries? How can those findings help in an evaluation of any specific situation? Should we give consideration to regulatory implications of technologies under evaluation?

As we’ll discuss at the SCTE Capacity Management Symposium, there are no simple answers when planning for the evolution of the network. While current market conditions deem it vital that we engage in capacity management and planning, our strategies need to be balanced against such factors as impact on the current customer base, return on investment and, of course, cost. As engineers, we must leverage our expertise to ensure that options are carefully and comprehensively considered, so that our industry can make decisions that will increase revenue and customer satisfaction, now and well into the future.

E-Mail: dhoward@scte.org

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