Video consumption has exploded over the last few years as more and more consumers are watching live OTT television content on smartphones, tablets, PCs, and other IP-connected devices. It has always been difficult for operators to predict the popularity of live video content, especially for major news and sporting events, and this becomes a problem when the dimensioning of the delivery system is directly related to the audience. Even when a content delivery network (CDN) is involved, the edge network becomes congested. This leads to a poor quality of service (QoS) for viewers. Investing in additional infrastructure equipment is too costly of an undertaking and would only be a temporary solution, as there would always be a need for more servers when live OTT consumption increases.

This article explains how operators can cost-effectively support peaks in live OTT multiscreen video consumption by leveraging multicast technology, in addition to outlining the benefits of multicast over unicast.

Multicast vs. Unicast Technology

Most television operators rely on unicast technology to deliver OTT multiscreen content. With unicast, every time a user requests a piece of content, a stream is sent throughout the entire network. If a significant number of users are requesting content, the operator’s resources are drained. This becomes quite a problem when millions of users want to simultaneously watch a live event. The peak in video consumption is simply too much for an operator to handle since each viewer counts as a separate unicast session. As live OTT multiscreen video consumption shows no signs of slowing down, a traditional unicast delivery method is becoming too expensive in terms of bandwidth and investments that must be made to maintain the network.

Partnering with a CDN provider only helps optimize the traffic on the backbone for known content. A sizeable infrastructure investment is still required at the edge of the network to absorb the load. The challenge for operators is how to support the growing demand for high-quality live OTT multiscreen content in the most affordable manner possible.

The most effective solution is to use multicast technology, even for OTT content delivery. Through multicast technology, television operators can stream live content only once in the network, regardless of the number of viewers watching, eliminating the impact of live content consumption peaks, which are very difficult to plan for given the fast-breaking nature of news and sports. The end result is that operators can serve millions of simultaneous viewers using only a few Mbps from the operator network. There are a couple of stipulations. The solution has to be transparent to the end device and should not require any modification to the subscriber’s display application.

When an advanced video delivery technology, like Broadpeak’s nanoCDN is employed, it allows the operator to rely on certain components of a subscriber’s home network, such as broadband gateways and set-top boxes (STBs), making them an extension of the operator CDN. After a CDN manager determines which live channels are popular and allocates the requests to either the nanoCDN or to the traditional CDN, the unicast streams are converted into multicast, allowing the operator to serve millions of viewers at once. An application installed in the CPE receives the multicast stream and converts it into unicast for delivery to individual devices across the residential environment.After the content has been delivered, the operator is provided with detailed analytics about the consumption of the services, the audience, etc., so that they can review the popularity of content and best allocate their resources during future live events.

Under the multicast approach, if 1 million live OTT viewers accessed the same live channel at 3Mbps on the network, the content is only carried once to a subscriber’s home, making the load for one channel across the entire network just 3Mbps. Yet, with unicast, the load on the network would be 3Tbps, which is a substantial difference in bandwidth usage.

A multicast approach is easy to deploy for operators since they already own a managed network with multicast capabilities. Furthermore, multicast technology is fully compliant with all DRM systems and does not require any specific implementation at device level.

Benefits of Using Multicast for Live OTT Multiscreen Delivery

Using multicast technology for live OTT streaming, television operators can dramatically increase their footprint without any impact on the network. Under this approach, the distribution infrastructure is not affected by usage. Once the technology is deployed, it can handle virtually any number of users without requiring operators to make an extra investment in network equipment. Thus, operators realize substantial operational and capital savings not only in terms of reducing bandwidth, but also by retaining the core network, access network (DSLAM), and CDN equipment.

This type of content delivery method also provides a more reliable quality of service, as the quality of the video content is only affected by a subscriber’s home network bandwidth. If an operator’s server is experiencing a peak in video consumption, there will be no impact on the subscriber’s quality of service.

Another benefit provided by multicast technology is that it resolves latency on the network caused by Transmission Control Protocol (TCP). When an operator’s servers are located far away from the end users, the roundtrip time to deliver content is higher, creating a delay on the network. Because a multicast delivery approach works with an end user’s home gateway rather than the server, it eliminates service interruptions, enabling consumers to enjoy a more unified multimedia experience across devices.

The benefits

Operators can contain costs with a nanoCDN, which scales very effectively. As the number of devices grows, nanoCDN ensure that the amount of bandwidth consumed in the core network is constant no matter how many users are watching it. This makes live OTT video delivery to any device truly scalable by extending the CDN infrastructure as far as the user’s home gateway. There is no need to add more servers or to dimension the system for peak capacity. With CDN costs controlled, the operator can offer customers more competitive prices.