Authored by Gregory Samson EVP Worldwide Sales Telco & Media
Between June 14th and July 15th of this year, many of us will be stuck to our sofa, a beer on the table and a pizza on order. The reason: FIFA’s 2018 world cup, that will take place across a dozen football stadiums throughout Russia. While sports fans are blissfully awaiting the event, OTT distribution networks are bracing for what could well turn out to be one of the highest viewing peaks in IPTV history. The difference between triumph and disaster will hold in two words: network scaling.
What’s the issue?
Conventional TV uses a multicast principle: one single media stream is broadcast, then picked up and displayed by all viewers. The same applies to multicast IPTV distribution, where everyone watches the same programme, using the same set-top box. But in today’s unicast streaming model (typically the case of OTT), every user gets a separate media stream, designed for their playback device. This is also what allows every viewer to pause, replay or record for later.
If too many users request media streams, beyond the infrastructure’s capacity, anything can happen. This includes unavailable streams, downgraded image quality, and buffering in the player displaying the video. To make matters worse, users confronted with buffering will usually relaunch their player, issuing another request and further building up the platform’s workload.
Ramping up the CDN infrastructure
In an OTT setup, distributors build their infrastructure around a packager and origin server upstream, serving the required media streams. The packager/origin server is supported by a content delivery network, or CDN, caching and delivering the streams to end users.
During viewing peaks, bottlenecks can occur between the CDN servers that are spread throughout the operator network that viewers connect to. This is the part of the infrastructure that OTT suppliers will need to ramp up in time for the FIFA championship.
Four options to choose from
The most obvious move is to add extra CDN servers as close as possible to the largest concentration of users. With a robust and disseminated CDN infrastructure, operators will maintain a multicast platform for IPTV traffic and keep the heavier unicast traffic for the multiscreen devices.
Another option is to implement multicast ABR. Home viewers using tablets or smartphones require separate unicast streams sent from the CDN servers. Multicast ABR allows these users to access multicast streams sent to the gateway in their home. This limits unicast streams to the user’s home WiFi LAN, freeing up the ISP’s network, including its last mile.
A third option to consider is using external CDN providers. Large content distributors will usually operate their own CDN servers, peered with local ISPs’ infrastructure. But they can temporarily boost their infrastructure by relying on external CDNs such as those operated by Akamai or Limelight, to handle part of their traffic.
Finally, one of the most forward-thinking options is to deploy an elastic CDN on a private or public cloud infrastructure using a virtualised software solution that could be activated only for the duration of the event. This move allows networks to reinforce their CDN infrastructure as required, without the upfront capital expenditure.
What’s the roadmap?
Experience has shown that the highest viewing peaks happen during sports events, reaching up to more than four times the regular infrastructure capacity. With this in mind, the challenge for OTT service providers will be to anticipate viewing peaks, as well as new registered users for those networks that will acquire exclusive rights from FIFA for the event.
OTT operators are currently scaling their capacities and will freeze their CDN infrastructure at least one month before the event.