7 CDN Alternatives


Is there an Optimal Strategy for OTT Service Providers?


Suddenly, it seems, we’re living in a CDN-alternatives universe.

When it comes to streaming premium video, OTT service providers have taken matters into their own hands by leveraging new cloud-based platforms to get what they’ve been missing from public CDN providers. Whether or not they can find what they’re looking for is the question we’re addressing here.

It wasn’t very long ago that one of the givens of the OTT premium video business was that you had to sign up with one or more CDN service providers to have any chance of delivering a viewing experience that consumers would be willing to pay for. Today, demand for cost-effective CDN alternatives, now known as “private CDNs,” is the new norm.

As reported in the recent CDN Forecast produced by Rethink Research, the volume of video traffic coursing through private CDNs running in data centers near targeted population segments is vying with the volume delivered over public CDNs in many countries. By 2024 private CDNs will carry 75% of video traffic in North America, Rethink says.

Why is this happening? In a word, live streaming.

While, in the premium OTT video market, traffic generated by on-demand viewing still outweighs live traffic two-to-one, according to the Rethink report, live will soon overtake on-demand. The researcher projects that by 2024 live streaming will account for 52.5% of total CDN video traffic.

Not that there wasn’t a move toward CDN alternatives before streaming of sports, news and other live TV programming burst on the scene. Even when subscription video on-demand (SVOD) was the only game in town led by Netflix, nobody was happy with the sub-par viewing experience that was synonymous with OTT – which is why Netflix became the first big SVOD player to build out its own CDN alternative infrastructure with all the capabilities it needed to deliver a first-class user experience.

And then, along came the next wave in the OTT revolution as “skinny bundlers” won licenses to offer linear TV programming online with an eye toward taking business from the established pay TV providers – or multichannel video programming distributors (MVPDs) in the awkward terminology preferred by regulators. As these new “virtual” MVPDs looked for ways to get closer to broadcast quality in their run at the incumbents, sports outlets from aggregators like ESPN, Eurosport and Sky Sport to a host of direct-to-consumer services mounted by individual leagues like the NFL, NBA, MLB and EFL (English Football League) were doing likewise.

Live OTT was now table stakes with no room for sub-par performance.

With cloud technology maturing and an abundance of compute resources to leverage in fairly close proximity to end users across much of the globe, there was no longer any reason to compromise on quality as the price for playing in the OTT market. As a result, over the past two years there’s been an outpouring of cloud CDN platforms designed to provide the CDN alternatives OTT providers need but at prices even small regional entrants can afford.


Claims and Challenges

Many of the big technology suppliers in the traditional TV business and some newcomers as well have come up with virtualized cloud solutions that purport to provide everything their customers need to deliver and monetize TV-quality OTT services.

But that’s a very tall order.

The ultimate test of a platform’s viability isn’t just whether it can support things like just-in-time (JIT) packaging at the edge as well as at the core with first-rate quality-of-performance on every stream to every screen. In a market driven by the demands of sports fans of all ages and a fickle generation of gamers, online kibitzers and tech dabblers, there’s nothing more important than the ultra-low latency in two-way video communications that’s essential to maximizing opportunities to deliver any latency-sensitive application that proves to have market appeal.

So are these new CDN alternatives taking the OTT business where it needs to go?

As we can see in a quick review of seven leading platforms, some solutions are better than others at doing various things. But the best bet for mounting a private CDN that will stand the test of time requires some new thinking.

Before we go down that road, let’s take a look at some of the leading options, including those on offer from Anevia, Harmonic, MediaKind, Synamedia, Vecima and Velocix as well as our own Red5 Pro platform.

All of these solutions rely on the availability of data center resources that can be used to position CDN-related processes close enough to end users to ensure a broadcast-quality performance. Commonly used techniques for reducing latency include Quick UDP Internet Connections (QUIC) and Chunked Transfer Encoding (CTE), which is used in conjunction with the Common Media Application Format (CMAF).

The exception in this group is Red5 Pro, which accomplishes ultra-low latency with multiple transport formats, including WebRTC (Real-Time Communications), SRT (Secure Reliable Transport), RTSP (Real-Time Streaming Protocol), RTMP (Real-Time Messaging Protocol) and MPEG TS (Transport Protocol), depending on source modes and use cases. Readers can explore the distinctions between CMAF/CTE, WebRTC and SRT in our blog titled Cross-Cloud Distribution System Alternative to Content Delivery Networks.

As for QUIC, this is an open-source protocol which, like WebRTC and SRT, enables use of UDP (User Datagram Protocol) as the transport mechanism for high-value video streaming, thereby avoiding the buffering delays intrinsic to TCP (Transmission Control Protocol). But vendors using QUIC, like those using CTE, fall far short of the ultra-low latency performance Red5 Pro achieves with its UDP-based options.


Containerized Virtualization

One prominent attribute common to all these platforms is the ability to leverage containerized virtualization technology. Most rely exclusively on this version of commodity off-the-shelf (COTS) appliance virtualization. Red5 Pro and at least one other platform, that of Velocix, supports other modes as well.

Container technology leverages the Linux kernel in server operating systems (OSs) to prescribe specific allocations of CPU, GPU and on-board memory for any given application or “microservice.” Microservices utilize application-layer OSs supported by Docker or other types of software containers, which allows multiple iterations of microservices to run on the same server through container interactions with the server OS kernel.

The popularity of Docker, the most commonly used container format, rests in part on its compatibility with the cluster management system known as Kubernetes. With this abstraction layer, microservices can be orchestrated to support complex applications that might require hundreds of containers running on multiple racks of server blades. These advances have eliminated the need to allocate hardware resources exclusively to CDN-related processes, which greatly reduces the costs of using public or private cloud resources for CDN applications.

Another benefit offered by most of these platforms is the use of edge-based packaging and, in some cases, transcoding, to minimize the live streaming traffic loads over core networks. In the case of edge packaging paired with core transcoding, the process reduces the core traffic load to a single iteration of each profile in the ABR ladder, leaving it to the edge packager to configure the unicast streams in response to client calls from end user devices.

With transcoding as well as packaging positioned at the edge, customers can use a single mezzanine encode for streaming live content to the edges before it is transcoded for unicast distribution to end users. As explained below, Red5 Pro takes another approach, which avoids edge-based transcoding while also minimizing the core network traffic load.

Taking them alphabetically before we get to Red5 Pro, here are the other CDN alternatives under discussion:


1) Anevia

Anevia, based in France, is a 15-year-old company that has built significant business for its “Elastic CDN,” transcoding and other cloud-based video service solutions in Europe, South America and Asia with clients that include France’s Canal Plus, Telefonica in multiple countries, Sweden’s Telia and Taiwan’s Chungwa Telecom. After pioneering the use of edge-based JIT packaging for ABR streaming, the company has added multi-platform transcoding and live-to-storage applications as options for deployment at its NEA-CDN edge locations.

Utilizing its high-speed transcoding support for QUIC-based streaming in combination with CTE, Anevia has shown it can achieve 2-second latency with live streaming scaled to reach millions of users. Placement of transcoding facilities at edge locations reduces core network congestion while adding just 100 ms. of latency, the company says. It claims it can keep latency within the 4-second range even with targeted placement of ads when customers use its dynamic ad insertion (DAI) edge solution.


2) Harmonic

The veteran San Jose-based supplier of encoding and other headend technology in the legacy pay TV market has added support for CDN-related applications to its growing portfolio of cloud-based solutions for MVPDs’ OTT service operations. The Harmonic delivery module is one of six virtualized microservices comprising its VOS platform, which also includes ingest, playout, graphics, transcoding and encryption microservices that can be implemented wherever compute resources are available. Through integration with ad decision servers, the delivery service is able to support both server- and client-side instantiations of DAI.

The solution, offered to MVPDs in software-as-a-service (SaaS) mode, extends the vendor’s VOS transcoding and packaging processes to edge nodes housed in customers’ facilities to facilitate live streaming at end-to-end latency in the five-second range. Customers continue to use third-party CDN services in conjunction with time-shifted content.

Reacting to incoming data gathered from CDNs, nodes and modems on a second-by-second basis, the service controller is able to direct each live stream over whatever turns out to be the fastest path at any point in time. In instances where traffic volume targeted to any given service area exceeds the capacity of the edge nodes, the delivery controller directs the traffic to whatever partner CDN facilities are best suited to sustaining low-latency delivery.


3) MediaKind

This New York-based Ericsson spinoff has expanded the portfolio of cloud-based solutions developed by Ericsson for the MVPD market to the entire OTT market. MediaKind’s distributed Media Edge modules operate as a complete CDN solution in synch with its private or public cloud-hosted Video Storage and Processing Platform (VSPP) to enable live streaming in the range of three to seven seconds.

Incoming content from contribution sources is ingested and transcoded to mezzanine formats at the VSPP and streamed out to the Media Edge nodes, which perform the JIT packaging and encryption for CTE-based unicast delivery to each viewer. In the case of non-linear content and implementations of time-shift storage with linear content. the edge-based processing capabilities make it possible to store just one copy to serve all devices in the service area. JIT packaging at the edge also supports dynamic advertising with MediaKinds’ DAI solution on linear as well as on-demand streams.


4) Synamedia

U.K.-based Synamedia is another video solutions provider spun off from a major player, in this case Cisco. Synamedia’s acquisition of Cisco’s Service Provider Video Software Solutions (VSS) portfolio and a global customer base exceeding 1,000 MVPDs has left the company in a good position to put the cloud to use in virtually any video service scenario. But while it has begun pitching the DTC market, it remains heavily focused on MVPDs with the burden of rectifying some well-publicized scaling failures that plagued Cisco prior to the spinoff.

The solution portfolio includes a Cisco-developed cloud CDN platform that ties in with Synamedia’s transcoding system utilizing CTE to deliver “near broadcast” latency, in the company’s words, at six seconds. The company also says it intends to support distribution via the still evolving Apple Low Latency HLS format, marking the first public commitment to doing so among the vendors discussed here. Early tests of Apple Low Latency HLS have shown latencies in the two- to three-second range at best.

The CDN platform employs JIT packaging to orchestrate time shifting with linear streaming and to achieve bandwidth efficiencies across the core network. Synamedia also touts an edge-based DAI option. The CDN along with other elements of the VSS portfolio is available as a managed service, which has been popular with large as well as smaller MVPDs and could help drive penetration in the DTC market.


5) Vecima

Vecima, an old-line Canadian supplier of QAM (quadrature amplitude modulation) products for the cable industry, took a leap into the CDN and other video storage-related spaces with its 2018 acquisition of Concurrent. Vecima’s solution set for the OTT market combines Concurrent’s strengths in object-based video storage with a master workflow system that collapses transcoding, encryption, packaging, storage and playout silos into a highly flexible, automated system for executing asset management across all distribution channels.

One of the unique aspects to Vecima’s cloud CDN solution is a transcoding system that’s coupled tightly to its storage platform through consistent communications between CPUs and hard discs. This greatly facilitates easy execution of multi-tiered recording for everything from live-to-file storage processing to end users’ trick-play and catch-up applications, the company says. With edge-based JIT packaging, reliance on QUIC and a variation on CTE that handles chunk-fragmented segments of ABR streams without reliance on the CMAF container, Vecima says it has reduced latency to two seconds.


6) Velocix

This U.K.-based spinoff from Nokia has tapped its pre-Nokia roots in making alternative CDN architecture the foundation for its business development. Employing CTE, the company says it achieves end-to-end latency on live streams in the five-second range.

Velocix is putting a high premium on helping providers achieve the best possible user experience on its CDN platform through use of personalized media extensions, including addressable advertising, developed by the former Nokia IP business group that now leads the company. Edge-based DAI, an optional component, has been uniquely designed to utilize JIT packaging in an ad-delivery architecture optimized to work with the on-the-fly bidding and purchasing mechanisms of programmatic advertising. The CDN edge also supports trick-play, restart and catch-up with live programming, personalization of user experience on a per-session basis and, when used with MVPD services, a direct tie-in with the vendor’s shared-copy approach to cloud DVR.

The company has strong credibility in the CDN alternatives space owing in part to its pre-spinoff work with Sky, which in 2017 became one of the first SVOD providers to mount its own cloud-based CDN architecture. The Sky CDN now supports a wide range of live and on-demand services in conjunction with a multi-CDN strategy that taps third-party resources when necessary.


7) Red5 Pro

Red5 Pro’s approach to alternative CDN architecture differs from all the systems discussed so far in multiple respects. Fundamentally, Red5 Pro’s innovations are targeted solely to minimizing latency and maximizing quality of experience on live streamed content while maintaining scale. In other words, if you want to mount a CDN alternatives supporting caching for on-demand content, you will need more than what Red5 Pro has to offer.

But, if you want to operate in an environment that’s been future-proofed for meeting the ultra-low requirements of video communications in all its permutations, you will need Red5 Pro. Whereas all the other platforms discussed here have managed to get latency down to broadcast and even sub-broadcast multi-second levels in some instances, Red5 Pro supports ultra-low end-to-end latency at 200 - 500 ms. with scalability to millions of simultaneous streams worldwide.

Details explaining the Red5 Pro architecture can be found in the previously referenced blog and in other on-site documents, including two white papers accessed here. Regarding Red5 Pro’s approach to minimizing core network congestion, this is done with any of the referenced transport mechanisms (WebRTC, SRT, RTSP, RTMP, MPEG-TS) while adhering to the profiles used with ABR streaming.

When processing an ingested live stream, the Red5 Pro encoder can be set to play out the stream in multiple profiles mapped to the typical ABR ladder. When the multiple versions of the stream reach each of the edge nodes after passing through the relay nodes in the Red5 Pro distribution hierarchy, the platform delivers whichever version of the stream is suited to each receiving device served from a given node based on real-time assessment of device parameters and access bandwidth conditions.

Clearly, as demonstrated by the hard work these other vendors have put into lowering latency on their platforms, once you get down to two or three seconds you hit a wall with any ABR-centric mode of delivery in a traditional CDN architecture. If we were living in a world where the goal in OTT distribution was merely to replicate broadcast TV, these limitations wouldn’t be a problem.

But the power of interactivity that comes with the move away from broadcast is increasingly going to be the factor that separates winners from losers in the battle for consumer allegiance in the crowded OTT marketplace. Whether by way of second-screen social interactions among sports viewers or via windows that bring those fact-to-face interactions in stream, real-time sharing of the viewing experience is a benefit OTT services can provide if they can meet the 200 ms. threshold intrinsic to wireline communications.  

Moreover, apart from interactions, once it becomes possible to witness what’s happening in real time on the playing field from anywhere a stream supported by Red5 Pro reaches, who will want to watch the same action with a multi-second lag time? Imagine a college dorm where some viewers are watching the quarterback take the snap while others are cheering for the completed touchdown pass.

Such considerations are especially relevant when it comes to the surging popularity of esports. People are socializing around action where the competitive standing among players waxes and wanes at lightning speed. Ultra-low latency is essential.

Massive multiplayer gaming, too, has become a mainstay in online activities. Services that improve on the lag times currently intrinsic to playing these games will prevail over those that don’t.

Other types of interactive online experiences are taking shape as likely ingredients to a compelling streaming service. For example, multiple types of auctions requiring real-time interaction between auctioneers and bidders are moving online. So, too, is casino-type gambling involving remotely located players that need to interact with dealers in real time.

What, then, is the best approach to meeting all the goals of CDN operations in this new world where live means much more than it did in the broadcast world and where, at the same time, scheduled viewing of episodic programming is no longer required? All of the CDN alternatives discussed here have something to offer, but only one has the essential performance characteristics essential to the trends taking shape around live streaming.


The Optimum CDN Alternative Solution

The obvious course for anyone choosing any of the CDN platforms offering support for on-demand distribution is to allocate the applicable cloud resources to the Red5 Pro platform as well. In such instances, the choice of the other platform can be based on considerations other than latency advantage, such as basic costs, whether one wants SaaS support, how devoted the supplier is to the category – MVPD, DTC or vMVPD – relevant to the buyer or the perceived importance of DAI.

Meanwhile, it’s worth noting that the public CDN providers weren’t sitting idly by as the once marginal domain of OTT video distribution became the mainstream conduit for video entertainment in the 21st Century. With competition driving prices down and operational enhancements based on the same technologies that once gave the suppliers of CDN alternatives an edge, many public CDN operators have rendered the perspective on their services from two or three years ago irrelevant.

Consequently, there’s just one investment in the CDN alternatives paradigm that’s essential. Once a service provider has put in place the ability to live stream content with interactive video communications support to millions of simultaneous users at sub 500 ms. latency, the question of whether spending is best placed on private or public CDNs becomes pretty much a matter of basic arithmetic and the nuances of specific needs. From where we sit, any combination of these options with Red5 Pro is far superior to one that overlooks the ultra-low latency mandate.

For more information on how Red5 Pro can help your live streaming application; send an email to info@red5pro.com or schedule a call directly. We would love to help.

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