RDK Emerges as Linchpin To Cable IP TV Migration

Philip Brennan, VP, TV technology, S3 Group

Philip Brennan, VP, TV technology, S3 Group

By Fred Dawson

December 10, 2013 – For backers of the cable set-top Reference Design Kit the moment of truth is at hand when fence-sitting MSOs will either come on board, securing the future of RDK as the cable roadmap to control over the subscriber experience in the home, or pass in favor of keeping options open amid a pell-mell outpouring of alternative approaches to accomplishing the same thing.

Momentum behind RDK has grown to where all the major set-top chip suppliers and leading set-top OEMs in the cable space have committed to RDK, bringing to over 100 the number of entities who have been licensed under the administration of RDK Management, LLC, the joint venture between Comcast Cable and Time Warner Cable. The latest publicly announced licensee, Samsung Electronics America, like other major set-top and gateway manufacturers, attests to the fact that the RDK initiative has achieved one of its major goals, which is to enable delivery of new devices capable of meeting individual MSOs’ service goals in record time.

“The RDK allows Samsung to deliver devices to operators faster and with broader scale,” said Stephen Goldstein, vice president and general manager for set-top boxes at Samsung Electronics America’s Enterprise Business Division. “Samsung has already begun deploying set-top boxes based on the RDK, and we look forward to more RDK-based projects in the United States and abroad.”

But so far, the only MSOs known to be licensed under the program are Comcast and TWC. Cox Communications and Liberty Global have expressed strong interest in using the RDK template, with Liberty letting it be known that it is using the software stack to migrate its Horizon media gateway user interface to the cloud. Other MSOs expressing interest in RDK include Charter Communications, Rogers Communications and Japan’s J:Com.

During a panel discussion devoted to RDK at the SCTE Cable-Tec Expo in Atlanta in October, Liberty Global’s vice president of technology Bill Warga delivered a strong endorsement of the RDK software stack based on what the company learned with early testing of the platform. “We saw incredibly good results,” Warga said. “We were pleasantly surprised.”

Indeed, according to informed sources, Liberty hosted a private meeting of European and other cable operators and vendors in Amsterdam at the end of the IBC show in mid-September in an effort to rally support for the platform. The importance of international support for RDK was underscored by the fact that IBC was the venue at which the RDK JV chose to announced the appointment of Comcast vice president of business development Steve Heeb as its president and general manager along with the selection of S3 Group and itaas to provide support services to the LLC and its licensees.

Of course, how many MVPDs (multichannel video programming distributors) are licensed is not a measure of RDK usage. As Steve Reynolds, former senior vice president of premises technology at Comcast who just became CTO of Harris Broadcasting, stressed before his departure, operators do not have to be RDK licensees to use products supplied by licensed manufacturers. But assignment of licenses is crucial to their ability to use the platform in their own development work.

RDK is definitely generating interest among cable companies worldwide, said Philip Brennan, vice president of TV technology as S3 Group. “A lot of operators we deal with are showing interest in RDK,” Brennan said in an interview. “We’re seeing a lot of interest outside the U.S.” This includes two European operators S3 is working with who “have chosen RDK as the basis for their next-generation products.”

S3, along with providing systems integration services for RDK and non-RDK related projects worldwide, is handling code management for the RDK JV. The company has created a code repository in conjunction with a rigorous code management process to ensure that contributions to the common code base are carefully assessed, merged and tested prior to being made available as part of RDK releases, Brennan said.

RDK, generally described as a pre-integrated software bundle to act as a common framework for powering IP and hybrid cable set-top and gateway devices, creates a uniform means of communication between chipsets and the middleware layer – in other words, a baseline hardware framework for leveraging on-board or cloud-based software strategies that leave ample room for innovation and sharing of those innovations among the RDK community. “RDK is essentially an app,” said Derek Elder, senior vice president and general manager of Touchstone CPE at ARRIS. “There’s nothing fundamentally baked into the chip.”

As an abstract layer between the middleware components and the SoC (system-on-a-chip), RDK ensures that when it comes to functions like tuning, decryption and de-multiplexing, the SoC is responsive to generic rather than proprietary commands that have traditionally been devised for each generation of chip and each brand of set-top. Thus, when a set-top manufacturer sets out to enable middleware functions specific to a given operator’s requirements, whether cloud or set-top based, the coding time required to build that software stack is cut dramatically. “At the fundamental level of blocking and tackling functions, RDK is establishing a stable environment that serves everybody’s interests,” Elder said.

Unlike OCAP (Open Cable Application Platform), the CableLabs specifications defining the set-top middleware branded as tru2way, RDK isn’t designed to determine how everything at the middleware layer is executed. Instead, it provides APIs to a variety of options, including OCAP and IP-oriented open-source processes like HTML5, WebKit, Gstreamer and QT to allow operators maximum flexibility in structuring their middleware operational environment.

“Embracing Internet standards such as DLNA, HTML5, and WebKit, and blending them with the RDK, will bring the best of the Internet into the cable environment,” said Shiva Patibanda, general manager of the In-Home business unit at SeaChange International. “We believe that RDK-based set-top software solutions will significantly improve time-to-market of cable set-top boxes on multiple SoCs.”

Indeed, noted S3’s Brennan, the industry’s efforts to bridge services into the IP domain is what will drive RDK penetration. “I think there will be a lot more interest in next-generation deployments, because RDK facilitates IP migration,” he said. “There’s a lot of stuff being done in the cloud that’s made easier by a generic platform the entire community can use.”

At the SCTE event Comcast’s Reynolds revealed that a forthcoming version of RDK will no longer require OCAP as a mandatory component of the software stack. OCAP will remain an option, Reynolds said, but the core means of setting up service flows through the set-top will be a new component known as RDK Media Framework, allowing operators to use the core as a “native IP pipeline” for building user interfaces and features without OCAP.

Given the growing consensus among MSOs around accelerating toward all-IP operations, this could be the game changer for RDK. A key question surrounding adoption of RDK has been the extent to which it can be a factor in near-term next-generation set-top and gateway deployments already in play among major MSOs. Increasingly, it’s looking like its real role will be to enable implementation of cloud-based operations built on IP while ensuring that RDK-compliant chipsets can also be used in set-tops and gateways that operate in the legacy MPEG-2 QAM-based service domain.

Another speaker at the SCTE event, Matthew Zelesko, senior vice president of technology at TWC, made clear his company’s interest is in the use of RDK as the foundation for new gateways that will converge all the company’s services on IP. As widely quoted in press reports, Zelesko said, “We’re looking at it for our IP set-top box product and the next generation of our gateways where we’re looking to converge voice functionality, high-speed data functionality and video functionality into one device.” He noted the company already has gateway products in play utilizing previously developed software stacks.

Similarly, Steve Calzone, director of video applications development at Cox, said his company is especially interested in RDK as the foundation for a full-service headless gateway – i.e., a gateway which is not attached to a specific TV but serves all devices in the home from a neutral location – that would deliver IP streams to all devices. But Cox hasn’t committed to that strategy and is concerned over whether RDK will support the special software elements and user interfaces Cox has already introduced.

Calzone also raised a question on the minds of many cable executives, which is whether RDK, for all the promotional and development energy evinced over the past year, could end up stagnating like OCAP. Where OCAP is concerned, notwithstanding years of drum-beating and widespread implementation in set-top boxes, the state of user interfaces and service features characterizing cable service in most households today attests to the fact that operators were unable to formulate business models sufficient to justifying the costs of moving to a next-generation platform in the home.

Now, with competitive pressures from the OTT domain, telcos and satellite, operators understand they can’t temporize in moving to next-generation TV, but the emphasis has shifted to ensuring subscribers can access the next-gen premium video service on connected IP devices inside and outside the home. Getting multiscreen TV Everywhere service off the ground has overtaken the move to next-generation set-tops, raising the question of whether operators can afford to wait until they’ve replaced current-generation set-tops to deliver a full lineup of linear and on-demand content to connected devices.

A whole raft of new options has come into play aimed at allowing operators to expand the TVE portfolio, prompting re-evaluations of the role of the set-top and, more importantly, media gateway in the whole scheme of things. For example, as previously reported, Liberty Global, amid its exploration of RDK, has also chosen to expedite expansion of its Horizon service by deploying the HTML5-enabled CloudTV platform supplied by ActiveVideo, which delivers user-selected content over either the traditional pay TV channels or over broadband IP without requiring replacement of legacy set-tops.

If the MSO is moving its middleware and UI functions to the cloud, as Liberty Global executives have said they are, the type of next-generation set-top to be deployed over time could change dramatically. In this scenario, with ActiveVideo, existing set-tops could be used to support the service as presently constituted, which is to say, with use of legacy MPEG-2 DVB channels augmented by Web-based content over the near terms, while RDK, with its orientation around cloud-based middleware, could be used to support a new generation of low-cost set-tops in conjunction with a switch to all-IP delivery of the core premium TV package.

Such a scenario for RDK has already been put on the table by Comcast. As the company puts RDK to use on gateways and set-tops in conjunction with its X1 and X2 Xfinity products, the need to ensure efficient distribution of these services across all devices has led the MSO to develop what it calls its VIPER (Video IP Engineering and Research) platform.

As described in a recent blog by Sree Kotay, senior vice president and chief software architect at Comcast, VIPER “streamlines the delivery of all professional content through the same broadcast-grade, programmable pipeline,” which “translates to a more consistent, cost effective, and high-quality viewing experience no matter where our customers watch – on TV, online, on mobile devices, on gaming consoles.”

The key to enabling such capabilities in the IP adaptive bitrate (ABR) streaming domain is what Comcast calls “just-in-time packaging,” meaning that the formatting of content into ABR “chunks” specific to the streaming platform and DRM used by any given device is done on the fly. As reported elsewhere, such capabilities mark a new dimension in TV Everywhere services that opens the door to monetization and personalization at mass user scales.

Starting with IP content delivered to the Xbox and moving to other devices, the VIPER platform is combining the packaging mode with a new Xfinity TV Player app, replacing third-party apps to bring its content to connected devices. “The Xfinity TV Player app is now one of the highest rated video applications in the iTunes app store,” Kotay said. In its first acknowledgement of a supplier in this space, Comcast has selected the VEX “manifest manipulator” or ABR packaging platform supplied by This Technology to enable dynamic ad placements on live and on-demand streams.

All of this is happening in tandem with preparations for the rollout of a new IP-only set-top, the Xi3, an RDK-based device which relies on the cloud-based content management established with the X1/X2 platform in combination with VIPER ABR distribution to bring legacy TV sets into the TVE domain. As Comcast moves to duplication of its full linear and on-demand lineup in IP, it will be able to begin offering an all-IP service without requiring installation of costly gateways. DVR functionalities, management of media, control over distribution policies to all devices, content protection, advertising and everything else will be managed from the cloud.

A piece critical to enabling cloud-based managed-service control across all devices is the CPE management platform developed by the Broadband Forum for the telephone industry known as TR-069. As previously reported, TR-069 has entered the cable modem domain, especially in the enterprise space, and now it’s set to become part of the RDK protocol stack with the next RDK release, according to informed sources, which means devices like the Xi3 as well as costlier multi-protocol gateways will be able to bridge service management controls to all connected devices in the home.

In other words, Comcast has put together the pieces in the cloud and at the end points essential to enabling migration to all-IP services. It will take much spending on network infrastructure, including implementation of CCAP (Converged Cable Access Platform) in the headend, implementation of private CDN infrastructure with the advanced streaming capabilities in place at all edge points and resolution of additional technical details to make this vision a reality, but it’s now clearly in sight.

While Comcast has put a lot of effort into developing the underlying technical framework for all this, it has done so with the participation of many vendors in the context of open protocols such as those embodied in RDK, which means the means are in the marketplace to enable other operators to move down a similar track without incurring the R&D costs Comcast has poured into these endeavors. Seen in this light RDK is an intrinsic part of what is destined to become the cable-optimized version of broadband TV.