Maximising CDN delivery performance

The logistics and economics of delivering Cloud DVR and Catch-up TV

A new era of connected TV is coming into being. But unfortunately, most networks are not ready for it, designed for it, or built for it.

Viewers increasingly want and expect complete control over when and where they watch, and on what device. Catch-up TV and Cloud TV offer new possibilities, freedom and flexibility, but the difficulties lie in making content readily available via these new channels whilst maintaining quality of delivery, and in monetising the opportunity whilst avoiding high capital costs.

Cloud-based Catch-up TV and Digital Video Recording (Cloud DVR) allow operators to replace costly home DVRs with single copy recordings stored in their network. In addition, they can make these recordings available beyond the living room TV, on tablets, smart phones and on the go. These services are clearly very attractive to consumers and the advantages look obvious. However, achieving them is not without its challenges.

Even though supporting the DVR set-top box model is highly expensive, delivering network DVR streams on demand to many thousands of simultaneous viewers can be equally costly if the wrong approach is adopted. If all recordings are stored in a few data centres in the central network, each and every stream to each and every viewer will have to pass through the same part of the network at the same time. Meeting the kind of peak traffic demand which that can create will require a sizeable investment in upgrading network capacity.

There is, however, an alternative which can avoid the need to upgrade the network, as well as offering better performance with reduced latency and less susceptibility to congestion.

The answer is to cache closer to the network edge, with all the savings that implies. But, of course, it’s not really that simple.

To achieve the necessary network offload, the edge caches must be able to serve the most popular content – a typical goal is 80% of the requests. Then only 20% of the content will need to be collected from the central data centres, creating load on the network. The amount of storage needed to achieve this goal varies greatly with the type of DVR service.

For example, a 24-hour catch-up service for just 100 SD channels would need 3.7TB of fast storage. But with each home DVR having up to 1TB of storage, and with viewers used to storing data forever, replacing set-top boxes entirely would demand an exponential increase in network storage capacity in the edge caches. In fact, storage becomes the major cost of the CDN.

But can caching really provide capital savings worth the investments, for storage intensive services such as Cloud DVR? Is it possible to find the optimum cost-effective balance between traffic levels and storage capacity? How do you make the crucial choice of the right Content Distribution Network?

Find out how the Edgeware Video Consolidation Platform (VCP) is already providing the solution – and savings – for one of Europe’s largest cloud DVR services, currently growing at the rate of around 100,000 new TV subscribers and several HD channels every month.

Download the Edgeware Whitepaper: Caching Cloud DVR and Catch-Up TV in the Last Mile


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