By Nivedita Nouvel – VP Marketing, Broadpeak
Netflix has emerged as a global leader in video streaming, largely due to its pioneering technology and commitment to delivering high-quality content. One of the key components of its strategy is its in-house Content Delivery Network (CDN), which eliminates dependence on third-party CDN providers. By managing its own cache servers placed within operator infrastructures worldwide, Netflix ensures that its videos are stored closer to end users, minimizing latency and optimizing streaming quality.
How Netflix’s CDN works
Netflix’s proprietary CDN is designed to handle unicast streaming. This means video is delivered on a one-to-one basis, with individual streams tailored to each viewer’s device and connection quality. The cache servers distribute video traffic locally, avoiding congestion on the broader Internet. This model works exceptionally well for Video-on-Demand (VOD) services, where content is pre-loaded and users access it asynchronously.
However, this system faces significant challenges during live streaming events. Unlike VOD, live streaming requires real-time delivery, and viewers often join simultaneously, causing a spike in demand. This sudden surge can overwhelm Netflix’s cache servers or the downstream network equipment, leading to degraded quality, interruptions, or delays in playback.
The unique challenges of live streaming
Delivering live content involves capturing, encoding, transmitting, and displaying video with minimal delay. Even minor imperfections in the network or transmission process are immediately noticeable, making live streaming particularly challenging. When millions of viewers attempt to watch live events concurrently, the unicast delivery model struggles to scale effectively.
Traditional broadcast TV overcomes these issues through multicast technology, which allows a single stream to be sent to multiple users simultaneously. This efficient method minimizes network load and ensures consistent quality. However, Netflix and other over-the-top (OTT) platforms rely on Adaptive Bitrate (ABR) streaming, a format that optimizes playback based on the user’s Internet connection but is inherently unicast in nature.
The Multicast ABR solution
To address the inefficiencies of unicast for live streaming, operators can use a solution called Multicast ABR. This technology combines the scalability of multicast with the flexibility of ABR streaming. Here’s how it works:
Stream conversion: In the operator’s headend, live video is encoded and packaged in an ABR format. The unicast stream is then converted into multicast for delivery across the operator’s managed network.
Gateway processing: At the user’s home, a gateway or set-top box converts the multicast stream back into unicast, allowing seamless playback on any device, including smartphones, tablets, connected TVs, and laptops.
This hybrid approach ensures that only one stream is transmitted over the network, no matter how many users are watching. The result is reduced network congestion, improved quality, and lower latency during high-demand live events.
The role of Multicast ABR in operator networks
Multicast ABR is particularly valuable for operators delivering high-audience live content. It reduces the strain on network resources, ensuring a consistent viewing experience even during peak traffic periods. By leveraging their existing multicast infrastructure, operators can offer third-party content providers, such as Netflix, the ability to stream live events without compromising quality.
Operators already use multicast for their IPTV services, where it delivers live TV to set-top boxes in a format known as MPEG-2 Transport Stream. Multicast ABR extends this capability to modern ABR formats, making it compatible with OTT platforms and their wide range of target devices.
Adoption and success stories
Multicast ABR has been widely adopted across the globe. Broadpeak has deployed its nanoCDN solution in more than 30 operator networks, serving over 30 million users. A notable success story involves DAZN, a major sports streaming platform, which uses Multicast ABR on TIM’s network in Italy to broadcast soccer matches. This deployment has significantly enhanced the viewer experience, reducing playback errors by up to 90% and cutting rebuffering times by 75%.
Future opportunities for Netflix
For Netflix, adopting Multicast ABR through partnerships with operators could solve many of its live streaming challenges. By leveraging operator-managed networks, Netflix could enhance the quality and reliability of its live events while reducing infrastructure strain. This approach would be particularly valuable for streaming high-profile events, such as sports matches or award shows, where audience demand peaks simultaneously.
Conclusion
Netflix’s investment in a proprietary CDN has positioned it as a leader in VOD streaming. However, the unique demands of live streaming require innovative solutions like Multicast ABR. By collaborating with operators and adopting hybrid delivery methods, Netflix can overcome the challenges of real-time content delivery and maintain its reputation for quality. As Multicast ABR continues to gain traction, it promises to reshape the landscape of live streaming, making it more scalable, reliable, and efficient.
