Edge Innovations for On Demand Services
Ran Oz
Chief Technology Officer
Introduction
Just a few years ago, the prospects for on-demand services over cable were highly uncertain. Initial launches met disappointing results, and some feared an overhyped phenomenon. But, true to its roots and culture, the industry has innovated on VOD offerings, and as subscribers get better senses of what's available and how to access it, success has set in. The industry's largest operator, Comcast, recently announced that it surpassed its goal of one billion VOD sessions during 2005 several months early. Other major operators are launching deployments of switched broadcast services which demonstrate that on-demand delivery applies to live programming as well. As competitive pressure on cable intensifies, on-demand delivery has emerged as a key point of competitive differentiation.
This distinction can be further established through a number of innovations with which cable operators can enhance their services. The experience can be extended to PCs in addition to TVs; targeted advertising can make free offerings profitable; partnerships can be entered with broadcasters that are increasingly open to making their content available for on-demand consumption; content can be extended towards more niche-oriented providers and even individual consumers who want to participate in providing video content. But these innovations must coexist among other cable industry priorities such as continuing HDTV expansion, the drive towards all-digital television by simulcasting, VoIP launches and increases in broadband Internet speeds. All make their own demands on resources and bandwidth, and cumulatively require continuing drive towards a more intelligent and dynamic cable plant.
With the development of digital content standards, extension of fiber to addressable nodes and increasing implementation of IP networking practices, among other developments, the cable industry is poised to extend its record of success across multiple services. There are a number of key technology initiatives to support this, including achievement of a flexible and intelligent network edge capable of key functionality such as dynamic QAM allocation including M-CMTS, rate shaping or rate clamping of sessions, open support for multiple conditional access methodologies, and progression of switched broadcast practices from multicast to unicast delivery. These can be utilized to enable on-demand provision of stored or live content, from multitude sources, towards any subscriber device.
This paper considers the increasing momentum of cable's on-demand activities and the competitive drivers to build on that success. A number of potential service innovations are explained. This is followed by a summary of related technological innovations including the imperative for more intelligent and powerful edge platforms that dynamically manage delivery of all services and media. Commitment to such initiatives promise to drive on-demand services growth as an important competitive differentiator within a context of overall expanding cable activity.
On-Demand Industry Imperative
Cable Launches On-Demand Services
As VOD was being developed during the 1990s, the most logical existing comparison was to the then-thriving movie rental business, and thus movies were anticipated to be the primary type of content provided. Cable operators devised plans for average session lengths of an hour or more with peak concurrency hitting 10%, meaning that at the service's most popular moments, one out of every ten subscribers who could access VOD would use it.
The earliest VOD implementations failed to meet these expectations, and a combination of subscriber unfamiliarity, content scarcity and alternative choices conspired to mire early peak concurrency somewhere much closer to 1% than 10%. Soon after, doubt was cast on the prospects of VOD to provide anticipated competitive distinction and drive new revenues for the cable industry.
With VOD infrastructure deployed, the industry has worked to develop new content offerings, and concurrency rates have increased. Subscription VOD offerings from premium channels like HBO have demonstrated that television programming offered live also finds interest by on-demand delivery. Cablevision's MagRack and other niche-oriented offerings spanning interests like collectibles and specific home exercise programs validate the Long Tail proposition that there is large aggregate demand when many specialized offerings are made available. And Comcast has had strong success with VOD versions of classified advertising, particularly a dating service based on accessing participants' video clips.
Cable operators have benefited from content innovations through concurrency rates increasing and the VOD success story materializing strongly. New offerings like Time Warner Cable's "Start Over" service in which subscribers can go back to the beginning of a broadcast show already in progress demonstrate the industry's commitment to continuing innovation.
With VOD practices more firmly established, the cable industry is now extending the concept towards live content, in addition to stored content. Switched broadcast makes virtually unlimited programming feeds available to be uniquely addressed towards only the nodes with live consumption. Several pioneering implementations have revealed strong potential for bandwidth efficiency gains, which is particularly important to accommodate the bandwidth demands of current initiatives like digital simulcasting, HDTV, faster high speed data, VoIP and VOD. But switched broadcast also promises to expand live offerings, just as operators are expanding their stored VOD wares.
Continuing Pressure from Competitive Environment
The need for cable innovation is underlined by the advances occurring in personalized video services from competing industries. Telecom operators seek to replicate VOD over IP networks. Internet content and service sites are expanding their video activities. Media companies are also working with the Internet as a means of delivering their content directly to consumers, without relying on intervening cable or telecom networks. Satellite operators, remaining hamstrung by their lack of return path or addressable network, look to advancing PVR capabilities to rival VOD.
Benchmarks for networked interactivity were established with the growth of Web popularity. Broadband connections have extended this to rich media, driving booms in music services such as Real Rhapsody and Apple's iTunes. Availability of podcasts developed by professionals or individual users to share content with other users is indicative of potential directions for VOD.
Internet services are now also moving towards video content, and media companies are beginning to directly participate. Apple has recently launched its video iPod as including an arrangement with Disney to make some of the most popular ABC shows available by iTunes. Viacom has recently acquired the popular iFilm Web service that streams short video files to users. Sling Media and Orb Networks are two start-up companies extending the PVR and NPVR concepts of time shifting towards place shifting, by enabling people to upload live and stored video content from their homes to access by video streaming over the Internet wherever they may be. Google had strong results in its video foray with the UPN network, making the first episode of "Everybody Hates Chris" available for a number of days on the Google Video site.
The potential of the highly anticipated Google Video service to stream personalized video to subscribers was demonstrated through a popular collaboration with the television network UPN availing the premiere episode of "Everybody Hates Chris".
The DBS industry established itself and grew based on breadth of broadcast offerings, but must contend with the expanding on-demand choices for subscribers. Both Echostar and DirecTV have identified integrated PVR with set-top boxes in efforts to emulate VOD. Echostar recently announced its PocketDish portable player that further expands flexibility for subscribers. These operators are contemplating how to use their spectrum to deliver specifically requested content to PVRs at off-peak hours for broader choice of offerings, although this would still lack the real-time capabilities of VOD services including networked PVR.
Echostar's PocketDish makes PVR content portable.
On-Demand Service Innovation Directions
While new entrants are developing and delivering interactive video capabilities, cable operators are well positioned with the most sophisticated and established VOD offering on a technically sound plant that leverages advances in networking, silicon and software. But the cable industry must continue pushing its on-demand advantages with further innovations in order to maintain strong positioning in key offerings for subscriber retention and new revenue generation.
Video to PC
As indicated in examples cited above, the IP networking experience is rapidly expanding to include video content, with subscribers expecting to be able to gain access from desktop and portable units in any location where they find themselves. With cable modem, DSL, fiber and WiFi competition driving up downstream bandwidth, this phenomenon is poised to increase.
Cable has an opportunity for strong success in delivering video to PC devices including VOD and switched broadcast, leveraging the industry's having facilities both for serving stored and live content, and for broadband access by PCs. Much of the usage increase in VOD has been driven by consumption of very short content, like Showtime's making available cartoon bunnies acting out popular movie plots in less than one minute. This is very consistent with the viewing durations that prove most popular for Internet video. Hybrids of switched broadcast with cable modem service could prove especially popular for sporting events and for the episodic and reality programs with the highest buzz factors, at moments when subscribers find themselves with access to PCs but not TVs, or when they want to follow the programming in the background while performing other PC-based tasks.
Because delivery of video is far more bandwidth intensive than the data and voice traffic currently driving much of DOCSIS usage, operators must consider their architecture in extending VOD service to PCs. Overall increasing of downstream speeds is a must, and developments like modular CMTS and channel bonding promise to support economical growth of overall bandwidth provided as well as the access speed available for individual sessions, key for developments such as HD-VOD to PCs. Also important is implementation of quality of service practices that assure real-time delivery, such as PacketCable Multimedia cable modems and CMTSs.
As DOCSIS video delivery takes an increasing amount of cable's overall bandwidth, operators should consider new approaches to managing their plants. With on-demand video to PCs emerging among other services that require high portions of plant resources at different times, the legacy approach of silos of frequencies for particular services may evolve towards a dynamic approach in which universal edge QAMs dedicate themselves towards whichever services are in real-time demand at any particular moment, from switched broadcast to PC-VOD to other services.
Advertising in On-Demand Content
Just as the Internet is driving new consumption patterns of video, it is radically transforming advertising models. Google has strongly established that delivering contextually relevant ads increases the interest of the user and value to the advertiser. The cable industry can replicate this model in delivering personalized services via switched broadcast and VOD. Digital ad splicing and ad targeting practices growing in broadcasting can be leveraged for extension of standards-based insertion to on-demand content with delivery to MPEG-2 equipment. In the case of switched broadcast, ads can be specified for each node in a multicast delivery model, or, in a unicast delivery model, specified for each subscriber who will be receiving an individual stream even when others in proximity are watching the same program.
A unicasting approach to switched broadcast can leverage on-demand delivery methods for different subscribers in the same geographic area, watching the same live program, to be served unique ads based on each one's demographic profile.
When subscribers request particular VOD or niche-oriented live content, that's a strong indication of their interests at the moment. A cumulative consideration of all of a subscriber's VOD and switched broadcast activity over time reveals an even more precise indication of interests. Subscribers can be offered VOD or premium live content for free or at discounts in exchange for their willingness to view some limited advertising. Because this advertising would be contextual, and more likely relevant to the subscriber, it could be sold at higher rates and therefore the amount of advertising would be reduced and likely isolated to a single portion of the program, which maintains distinctive subscriber experience versus traditional ad-supported broadcast television.
Another important element of Internet advertising which on-demand delivery can help bring to the cable industry's television services is interactivity. An Internet user can click on a banner, button or textual ad to get more information on what's advertised and enter a transaction. Television ads can similarly trigger on-demand perusal of longer form advertising. If a subscriber indicates interest during an ad, the primary content being watched can be paused for resumption later, while the subscriber views a longer form ad via VOD navigation.
Long form advertising by VOD can be extended to live television content. When a subscriber requests particular content, the live programming can be paused for resumption whenever the advertising perusal is completed. This is available even to non-PVR televisions by practices described in the next section. Because many service innovations to advance advertising sophistication within on-demand content involves personally targeted content delivery, the network edge plays a vital role since this is the point of significant content processing and routing closest to subscribers.
VOD Broadcast Integration
The notion of appointment-based television is fading. PVRs and subscription VOD remove requirements for particular programming to be viewed at particular times. And the onset of portable PVRs and devices that upload television content from homes for consumption over the Internet similarly open possibilities of where content can be watched. As demonstrated by collaborations like ABC with Apple, and UPN with Google, as well as Viacom's acquisition of iFilm, content owners are increasingly open to liberating how their content is made available.
The cable industry has strong positioning to collaborate with broadcasters on making more programming available on-demand. Because of the cable network configuration, the industry can control how content is delivered whether for on-line VOD usage, or delivery for storage by PVRs or PCs for off-line consumption when subscribers choose. The degree of advertising integration, including whether or not ads can be fast-forwarded, can also be managed. Importantly, control can be gained over how many times content can be played or copied per individual subscriber.
Integration of VOD with broadcasting can also be combined with advertising integration for additional functionality. A subscriber watching personalized delivery of programming can have subscriber-relevant content spliced within it for maximum attractiveness for advertisers. This sort of capability can be achieved on subscription VOD, networked PVR, or delivery of content to PVRs or PCs for storage and off-line consumption, and, as noted above, the proliferation of switched broadcasting can extend such personalized advertising insertion to live programming as well.
On-Demand Content Proliferation
As this paper notes, on-demand viewing has spread from movie content to popular television programming to more niche-oriented fare. This trend is consistent with the "long tail" phenomenon that if enough content is made broadly available, then the cumulative demand will include a substantial portion across the least popular content. This has been substantiated in video by NetFlix, which achieves much of its rental traffic with titles that individually don't generate sufficient demand to economically justify availability in physical video establishments.
The types of content that can be made available by VOD and switched broadcast are practically unbounded. This includes international, educational, training, professional, enterprise-oriented, and performances and sports events, among other potential categories. All can either be provided live from anywhere, or captured to storage and provided by VOD.
However, as content gets more widespread, cable operators face considerations of how to architect their systems. Initially most storage for VOD was integrated with QAM modulation and pushed out to edge locations. As the storage and modulation elements became decoupled, more servers were put in centralized headends to save on memory resource requirements. More recently, a hybrid model has taken hold in which more popular titles such as recent hit movies get located back at the edge to conserve on transport requirements. But, as VOD expands down the long tail, the amount of content provided presents a challenge for storage even at centralized headends.
Networking transport, which is increasingly used with video content for broadcasting, can present a solution for widespread expansion of VOD content. Instead of operators needing to store every title in every system, they can centralize to specific facilities that service all of their systems, or collaborate with content providers who can manage their own storage on their facilities. Either of these approaches can leverage the nationwide dark fiber networks that many cable operators are increasingly managing. When a subscriber requests a program, it can be signaled from the local system to the storage content's facility anywhere in the country. This could even be conducted internationally. Key to achieving this is implementing wide area optical transport based on Gigabit Ethernet, with robust de-jittering and potentially service-level redundancy.
On-demand participation can spread beyond just content owners to also include content made available by individual consumers including cable subscribers. This too is a strongly established recent Internet phenomenon for non-video content as in trends like blogging and wikis, and towards richer media forms, as in podcasting. The recent launches of the television network CurrentTV and Internet start-ups like Bright Cove and DaveTV are based on consumer interest in publicizing and distributing their own video content. While it may be many years before consideration is given to how consumers can post live content by switched broadcast, enabling consumer uploading of files for VOD storage is feasible in the near term.
Cable can prosper in expanding VOD content participation to consumers through arrangements such as availing server space, which is consistent with some services already launched such as Comcast's video dating. Another important direction for consumers serving their own video will be expanding upstream broadband speeds, as IP is the most likely practice for individuals to put their VOD content onto servers.
As sourcing of on-demand content spreads to more sources with wider geographic distribution, and operators implement their own hybrid server location architectures, it is again the network edge location, where all live and stored on-demand sessions are aggregated, that emerges as a key point of technological integration.
Infrastructure Support for On-Demand Innovations
While VOD and switched broadcast in particular are compelling competitive distinctions for cable, their growth must be considered in context with other important and growing services including all-digital expansion, HDTV, VoIP and tiered high speed data. So rather than optimize for any single service, the industry must consider how to continue advancing the plant for growth across multiple services and media.
Overall, the cable industry has advanced during the last several years by leveraging its increasingly versatile, intelligent and high capacity infrastructure. The construction of the HFC plant has resulted in widespread fiber use, multiplexing of digital content and delivery towards addressable nodes and subscriber devices. Continuing development along these lines is key to ongoing growth.
In considering the current state of the cable industry, bandwidth expansion escalates to be a primary concern. VOD taxes heavily by consuming an entire node's or service group's bandwidth for delivery of content to a single subscriber. HDTV has grown concurrently which presents bandwidth concerns by consuming several times more bandwidth per stream than standard definition programming. These trends come together for HD-VOD, a great opportunity for cable to distinguish itself from other service providers including both Internet services and capacity-constrained telecommunications operators, which of course ratchets up the bandwidth management imperative even higher. And this must be executed at the same time that further claims on bandwidth are made by the growth of VoIP and higher speed Internet access as well as simulcasting both analog and digital versions of basic cable offerings. Related to VOD in delivery mechanism, switched broadcast is a proven saver of bandwidth when applied by multicasting to already offered programming, and should continue to be a net conserver of bandwidth even with unicast delivery and expansion of content offered.
Better bandwidth management by practices like switched broadcast, among other drivers like open systems operations and increasing leveraging of IP, have driven the development of next generation network architectural plans. Several of these developments promise to support VOD and broadcast growth, and other innovations within a context of multi-service expansion.
Versatile Edge
The hub-based network edge is the key strategic fulcrum for growth of digital services. This is the point at which all services - live or on-demand; passive or interactive; video, voice or data - commingle for their final high-level processing before being routed towards subscribers. In the context of VOD, this is vividly realized in the possibilities for more hybrid server architectures including storage at hubs, headends, national aggregation points of operators, and national and even international aggregation points of content owners. At the edge, these sessions from disparate sources meet HDTV, SDTV and analog broadcast streams, also potentially sourced from anywhere in the world, local advertising insertion, and DOCSIS sessions.
With growth across so many different services, a major potential driver for better bandwidth efficiency is to break the legacy silo approach and migrate towards dynamic bandwidth allocation. Switched broadcast does such dynamic allocation in response to live consumption within a broadcast silo, as do VOD and DOCSIS within their respective silos. Instead of assigning fixed resources to each service, an approach based on cross-service and cross-media packet switching can even more significantly enhance bandwidth management through statistical multiplexing that leverages offsetting peaks and takes advantage of different quality-of-service requirements between real-time and less sensitive media forms. The platform for cross-service multiplexing and dynamic bandwidth allocation is the universal edge QAM that brings together multiple digital sessions and takes advantage of all receiving the same QAM256 modulation.
A universal edge QAM approach advances concepts of switched broadcast, distributed VOD and modular CMTS to enable greater bandwidth and resource efficiency by allocating QAM256 capacity openly across multiple digital services.
There are a few key current initiatives driving multiple services towards participation in universal edge QAM. Both switched broadcast and VOD use highly economical edge QAMs to direct content only towards the nodes with specific demand. Modular CMTS separates DOCSIS MAC routing from physical QAM so that the same beneficial edge platform modulating digital video can extend towards IP services as well. A further expansion of bandwidth efficiency, in addition to universal edge QAM, is performing block upconversion of multiple channels, further achieving cost reductions.
Edge aggregation of all services also creates opportunities to implement more open encryption practices for all content types, including session-based encryption of VOD or switched broadcast. Before being delivered to the QAM, content can be routed through multiple parallel encryption servers, based on the equipment and software on the premises of the particular subscriber. This illustrates further benefits of open edge platforms by liberating operators to select conditional access systems from any vendors and liberating subscribers and operators in terms of what customer premises equipment are supported including multiple set-to boxes.
An architectural approach incorporating open edge QAM with switched services liberates choices of conditional access methodologies and customer premises equipment.
While the progress towards universal edge QAM is highly enticing, necessary elements such as switched broadcast and modular CMTS are just beginning to mature. There are several key elements of edge media processing for managing bandwidth and service challenges in the mean time.
One of the most interesting recent service launches is Time Warner Cable's "Start Over" service in which a subscriber can jump back to the beginning of a live broadcast program in progress by delivering as a VOD stream. The same functionality could be implemented in order to enable subscribers to pause a live broadcast program while perusing a selected long form advertisement. In order to introduce digital broadcast streams, such as those re-started or those resumed after pausing, into the VOD multiplex, it must be converted from its variable bit rate nature to whatever constant bit rate is used for VOD streams in that system through bit rate clamping. This same processing is performed for similar reasons on switched broadcast sessions.
The drive for clamping is in order to simplify the management of multiple sessions at the edge by not requiring consideration of each single session's real-time bit rates. However, such a process enables statistical multiplexing of variable bit rate programs, which can significantly expand the number of streams per multiplex, as experienced in digital broadcasting. As an open edge becomes increasingly implemented, Moore's Law advances can be leveraged for performance of statistical multiplexing with rate shaping of particular sessions of VOD and switched broadcsast.
A major current impediment to edge-based rate shaping of VOD and switched broadcast content is the difficulty of economically performing processing on a stream only delivered to a single subscriber. The associated bandwidth efficiency gain tends not to justify the processing cost. However, this may be overcome through centralized analysis of stream complexity so that the data that drives rate shaping is only performed once, and then multiple versions of a stream can be created based on the data. Each stream can be transported to hub locations, where the multiplexes for each node are dynamically constructed. When a program resides within a multiplex at a moment of peak overall bandwidth requirement, a lower bandwidth portion of that program can be selected, and when the bandwidth pressure is alleviated, a higher bandwidth section of the same program can be dynamically implemented.
The bandwidth benefits of statistical multiplexing and rate shaping can be realized for dynamically provisioned content like switched broadcast by delivering multiple stream profiles to edge locations that select the version best fitting real-time capacity.
IP Bandwidth ExpansionExpanding VOD and switched broadcast services to include delivery to PCs and other IP-based devices drives an additional demand on the network edge. Uptake of other video services by IP is likely to significantly expand the demands on the DOCSIS infrastructure. Several new developments promise to support this.
Modular CMTS enables IP bandwidth expansion at much greater economic, resource and space efficiency. Disaggregating DOCSIS MAC from QAM enables operators to take advantage of video edge QAM advances in cost effectiveness and density. Some solutions promise to multiply the DOCSIS capacity per chassis several fold, while performing associated modulation in an even smaller footprint, and with an overall cost at a fraction of legacy CMTSs. Because the edge QAM can be the same platform used for switched broadcast as well as MPEG-2 VOD modulation to set-top boxes and cable-ready digital televisions, this provides a path towards universal edge QAM.
More video delivery by DOCSIS also drives for implementation of channel bonding in which multiple downstream channels are combined to achieve speeds of over 100Mbps. While this is well beyond the requirements for any single stream, even at HD quality, channel bonding does provide for bandwidth efficiency gains by enabling more high bandwidth sessions to be efficiently statistically multiplexed together. And, while it is difficult to anticipate what service would require such high bandwidth sessions, general industry patterns reveal that when bandwidth is availed, innovations in services tend to utilize it.
In addition to greater downstream bandwidth, on-demand innovations may also drive increasing upstream traffic. Drivers include individuals seeking to produce their own VOD content, or simply serve content to themselves from their homes to remote locations. More variables in IP services and how they are used drives priorities to break the fixed upstream to downstream ratios for greater flexibility to meet service requirements, including dynamic load balancing in both directions to accommodate temporal peaks and valleys in traffic across nodes.
Anticipation of greater video delivery by DOCSIS drives reconsideration of CMTS infrastructure overall for greater flexibility. This includes open migration from integrated CMTS to modular CMTS including universal edge QAM, selective implementation of channel bonding with support for legacy cable modems in order to not force complete swaps, variable downstream to upstream ratios, and dynamic load balancing across nodes.
Additional Functional EnrichmentVOD is inherently an interactive, functionally rich service, but it can be further enhanced with incorporation of additional interactivity. This includes layering on DVD functionality, content-themed gaming and transactional capabilities. Just like VOD and HDTV before it, interactive television is a service currently considered to be behind expectations in adoption. But such integration within other services may drive its growth.
Providing VOD and live switched broadcast content from various headend, edge and centrally aggregated locations, including some on third party premises requires extensive management capabilities over assets and resources. With progress towards universal edge QAM architectures, there are calls for global resource management integrating management of all content, services, sessions and subscriber devices. Additionally important is that transport be conducted with robust de-jittering at the edge due to the diversity of distances. And it is also worth considering redundant paths to the edge with service level sensitivity to switch to alternative feeds, especially for live content.
Another example of competitively attractive service enhancement that cable operators can achieve from an enhanced network edge is providing instant channel changing through switched unicasting. There is latency in digital tuning mostly due to the algorithmic nature of MPEG streams and the fact that reference frames are required to initially resolve images. With unicasting, in addition to no requirement for the tuner to retune when the subscriber requests a different program, that program can be delivered with its current reference frame first for instantaneous resolution. This is an illustration how versatile edge platforms, converging VOD, IP and live switched broadcast services, can be leveraged to enhance the cable industry's competitive positioning.
Conclusion
While the cable industry is facing its most intensive competition, it is also poised to extend its streak of innovative leadership, especially with the personalization of rich media achieved in on-demand delivery models. Current initiatives such as VOD and expanded choices through switched broadcast meet enthusiastic subscriber interest. The benefits of assets such as fiber plants, addressable nodes and increasing utilization of IP technologies provide strong advantages over alternative providers who tend to lack the cable combination of high bandwidth access with a sophisticated switched network.
But, changes in the markets for digital service delivery are occurring with unprecedented rapidity across a vast array of considerations. There is an imperative for cable positioning to synthesize across this diversity and be positioned for ongoing flexibility. This elevates the strategic importance of the network edge - the point at which all services of all media from all sources co-mingle for their final processing and routing before delivery to subscribers.
At such sites, a key pending innovation for greater delivery of personalized services such as VOD and switched broadcast is the onset of the universal edge QAM. Such platforms can openly allocate bandwidth to any digital service in accordance with real time demand, and support advanced functionality such as opening conditional access choices and efficient statistical multiplexes of on-demand content with rate shaping. Intelligent and flexible edge infrastructure enables cable operators to expand and optimize on-demand delivery of content, with abilities for ongoing innovations that extend the industry's competitive leadership.