Pay TV: use CDN to avoid becoming ‘toast’
Pay TV operators face two immediate challenges when it comes to delivering content in a multiplatform world: to provide consistent services and to contain costs. If they get these right they will then be able to meet a third even greater challenge, which is to avoid being toasted by emerging OTT (over-the-top) providers squeezing them out of the content value chain. They can do this by making high quality and low cost content delivery their speciality, which requires deploying the latest technology for moving video efficiently both to the end customer and within their own networks.
This is happening against a background of migration towards IP based optical fibre based networks, which will account for an increasing proportion both of video contribution and distribution over the next few years. This will give established operators a leg up over their new rivals in the OTT arena by virtue of their expertise in dealing with different end client devices and in delivering content securely, according to Murali Nemani, Director of Video Solutions at Cisco. There is more to moving content in his view than just shunting packets of data around.
“Service providers should become conduits for content to come through and enable consistent experience scaleably across multiple end points,” says Nemani. “Then consumers can seamlessly move between devices with the consistent experience they are used to.”
In this way, operators can add value to the business of content delivery, which can itself become a source of revenue rather than just the medium for delivering service to end customers. “For service providers it is a win because their service becomes more valuable and, more importantly, it enables them to make the network valuable,” says Nemani. “It’s also a win for content providers, because at present they have to transcode and transrate every piece of content and keep up to five physical formats.”
With the service provider delivering the content as a cloud based service, adaptation to the end device and implementation of appropriate security mechanisms can become transparent to the content provider. But the actual movement of the content itself can also give operators competitive advantage, according to Nivedita Nouvel, VP of Marketing at French multiplatform delivery technology vendor Broadpeak. As Nouvel points out, many content owners have come to rely on dedicated providers of Content Delivery Networks (CDNs) for video, such as Akamai and Limelight, to reduce the cost of delivering popular material consumed by each user independently on a unicast basis.
CDNs solve two problems at a stroke. Firstly, they reduce the load on the core or backhaul network by distributing popular unicast content to caches nearer the user. Secondly, they reduce the total delay, or latency, taken to respond to requests from the user, which can be important for interactive applications.
In this way, CDNs will be the most vital component of future hybrid networks combining unicast and multicast/broadcast delivery within a common infrastructure. Then the most popular channels and events might be broadcast to everybody, while rare niche events would always be unicast.
However, a large amount of content – call it the mid-tail – might be either unicast or multicast depending on varying demand at different parts of the delivery network. Suppose somebody requests a particular channel within a given operator’s domain. Then that channel would start being streamed on a unicast basis to that customer. But if several more people wanted to view that channel at the same time, and that could apply to a single event such as a football match as well, then it becomes worth streaming the content once to the last common point of access for those users, and then unicasting from there.
That process is effectively multicasting and a CDN can make that more reliable and efficient by providing a dedicated network for the multicast delivery to caches nearer the end points. The on-demand capabilities of the CDN would cater for dropped packets and enable fast channel change, by being able to deliver small amounts of the relevant content rapidly.
Nouvel believes there is scope for Pay TV service providers to become successful CDN providers, particularly within their operating regions, by going right to the user and guaranteeing end-to-end QoS (Quality of Service), which existing dedicated CDN companies cannot do at present. “The problem content providers have when they deal with Akamai is they don’t have guaranteed end user quality of service,” declares Nouvel, adding that the global CDNs do not necessarily take the optimum route when carrying local traffic.
Nouvel continues: “Akamai and Limelight will still score carrying intercontinental traffic, but when talking about paid content, especially catch-up TV, why should the traffic go through Amsterdam or Italy with Akamai, when it could stay in France?”
Both operators and dedicated CDN providers have scope for reducing their storage and bandwidth costs through optimal routing and location of content within their networks. Broadpeak is one vendor supporting that process through software that helps operators decide how best to respond to changes in demand, both to move content to the best node or point of presence, and to locate it in the most cost-effective form of storage within each server.
Storage for video comes in three categories of increasing performance and cost per unit of data: disk, flash and RAM. To give a quick and rough thumbnail, disks take on average about 4 milliseconds for each read access, which is a relevant measure for video access, while flash is up to 40 times quicker for reads at 0.1 ms. RAM is about 10 times faster again at 0.01 ms. But costs go the other way so operators will save by using RAM only when needed for the most heavily demanded content at a given time. “According to the popularity of content, our CDN mediator can move it dynamically from one type of storage to another,” explains Nouvel. “The mediator keeps track of which content is more popular, which allows operators to move content between Points of Presence as well as within each server.”
It might be thought that operators would want to automate this process of shifting content about to optimise performance and cost, but instead they still prefer to do that themselves. “Operators normally like to decide themselves when and where to move content,” says Nouvel. This, he adds, is largely because other factors beyond the scope of the Broadpeak system also determine the best place to locate content at a given time, such as knowledge of a future event that will affect its popularity. This could be the start of a new TV series expected to be popular, in which case the operator would anticipate the demand and move content in advance.
But there will also be unpredictable factors such as a breaking news story. So the ability to react quickly to fast changing events on an automated basis is likely to become an important feature of competitive CDNs in future. In effect such CDNs bypass the unmanaged part of the Internet, with the implication being that high quality video services cannot really be delivered on the same ‘best effort’ basis as, say, email.
That still leaves the question of the end device, which in the emerging multiplatform world will not always be within the direct control of the operator. Cisco’s solution to this problem is to download a software client to the end device enabling a content owner, or another service provider, to give the end user a consistent interface and experience. “The soft client Cisco provides allows you to load a client that represents your user interface and EPG as if they were on a TV set,” said Cisco’s Nemani.
BT Wholesale’s Content Connect is one CDN based on Cisco products, and Simon Orme, the company’s Strategy Director for Content, argued at the IP&TV World Forum that the ability to reach the expanding plethora of mobile devices, including tablets as well as smart phones, was a great opportunity for CDN providers. His argument is that 85-90% of mobile data, including video, is consumed indoors, often within the user’s home, and so can readily be sucked into a fixed line broadband network underpinned by a CDN.
“The real growth in a mobile environment is all around data and content services and we see that as a major opportunity for us,” said Orme. “As the mobile data explosion matures we see more and more of that end-to-end mobile data migrating back into the fixed line environment.”
It could then be that multi-screen services including mobile are delivered on a common broadband network, bypassing even the cell towers, and connecting with the user either via Wi-Fi or femtocells hooked straight into a DSL or fibre connection.
Related content:
CDNs get smarter, ready for Connected TV
Broadband ready to become a serious TV platform
HD Connected TV needs telco CDNs
Video: CDN analytics improves QoS and boosts content business
Video: Operators need their own CDN for TV Everywhere
Philip Hunter is a technology journalist specializing in the business and delivery of video and digital entertainment.
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