Be prepared for the unicast flood!

“Consumers just can’t get enough video” as a Bell Labs study reported recently.

It’s not just the amount of time consumers spend watching video that is increasing, it’s also the way they consume content that is changing. And this has a huge impact on the networks delivering that video. When people watch Live TV on their television sets, it is broadcast or multicast TV, which means the same stream is distributed across the network to all the viewers at the same time. But when people watch video on IP connected devices (smartphones, tablets, PC, etc.) or when they watch on demand content (VoD, catch-up TV, network DVR, etc.), it is unicast traffic: each individual user is served with a unique stream.

Time spent watching video, per user, per day in the United States in 2012 and 2020

The Bell Labs study says that in 2022, unicast-type video will represent more than 90% of the demand.

This is raising unique challenges for service providers who have to scale their networks to support unicast traffic. Let’s take a closer look at the evolution of pay TV traffic in an IPTV or cable operator’s network:

Looking first at the types of devices on which pay TV is consumed, video to IP connected devices (which requires unicast) is set to explode, from only 20% of video traffic today, increasing to 80% in 10 years.

From another perspective, if we look at the types of services consumed, whatever the devices used, time-shifting (which also requires unicast) will grow from 15% of video traffic to 60% over the same period of time.

Time shifting refers to watching previously aired programs on demand but it also typically includes bingeviewing. Binge viewing has been popularized by over-the-top providers such as Netflix and consists of devouring shows in quick succession, episode after episode, season after season.

Evolution of traffic for video services offered by network operators (IPTV and cable) in US due to multiscreen and on demand viewing

Many operators say this phenomenon has started already and they are investing to ensure they can better serve their subscribers at the lowest cost. In this 5-min video you can hear some of our customers – Swisscom, Telus and Time Warner Cable – discussing this surge in unicast traffic and describe the paths they have taken to prepare their networks.

Watch the video: Preparing for all-unicast migration

It’s pretty clear that Content Delivery Network (CDN) will play a critical role in helping operators optimize their networks for unicast traffic. The basic idea of a CDN is known as “caching” – storing content close to subscribers at the edge of the network so that every time someone requests a video, they are served from this cache instead of being served from a central server. This means the content travels a shorter distance to reach the screen. This is better for the operator who needs less capacity in the core network. It’s also better for the end user who can expect a better quality.

But there is more to come for CDNs.

Unicast means the stream is unique to each user, which also means content can be unique, or at least part of the content. We call it content personalization, and it opens up new possibilities in terms of advanced video services. One classic example of personalization is targeted advertising.

To retain the cost and traffic management benefits of the CDN, it means this personalization has to be performed in the CDN at the edge of the network: the common part of the content is sent once from the central location to the edge where a cache introduces the personalized piece to the stream as it is delivered. Of course, not every basic CDN can do that. This requires some tight integration with back office platforms and some level of intelligence to process the content. This is the next step for CDNs, as I am describing in this paper.

Consumers just can’t get enough video, this is true. On the downside, this means operators have to invest more in their networks to cope with the increased traffic. But the good news is that they have to tools to cope with the demand and these tools can help them make the video experience unique and personal!