Measurement Study of Netflix, Hulu, and a Tale of Three CDNs

Netflix and Hulu are leading Over-the-Top (OTT) content service providers in the US and Canada. Netflix alone accounts for 29.7% of the peak downstream traffic in the US in 2011. Understanding the system architectures and performance of Netflix and Hulu can shed light on the design of such large-scale video streaming platforms, and help improving the design of future systems. In this paper, we perform extensive measurement study to uncover their architectures and service strategies. Netflix and Hulu bear many similarities. Both Netflix and Hulu video streaming platforms rely heavily on the third-party infrastructures, with Netflix migrating that majority of its functions to the Amazon cloud, while Hulu hosts its services out of Akamai. Both service providers employ the same set of three content distribution networks (CDNs) in delivering the video contents. Using active measurement study, we dissect several key aspects of OTT streaming platforms of Netflix and Hulu, e.g., employed streaming protocols, CDN selection strategy, user experience reporting, etc. We discover that both platforms assign the CDN to a video request without considering the network conditions and optimizing the user-perceived video quality. We further conduct the performance measurement studies of the three CDNs employed by Netflix and Hulu. We show that the available bandwidths on all three CDNs vary significantly over the time and over the geographic locations. We propose a measurement-based adaptive CDN selection strategy and a multiple-CDN-based video delivery strategy that can significantly increase users' average available bandwidth.

I. Introduction

Netflix and Hulu are the leading subscription-based video streaming service providers for movies and TV shows. By April 2014, Netflix has attracted more than 35 million subscribers in the US alone and about 48 million worldwide [1]. It is the single largest source of Internet traffic, consuming 29.7% of peak downstream traffic in 2011 [2]. Like Netflix, Hulu also has a large viewer base, with 38 million casual viewers who watch Hulu at least once a year and 3 million paying subscribers. Both providers offer video at multiple quality levels, capable of adapting to the user's available bandwidth. Designing such large-scale, fast-growing video streaming platforms with high availability and scalability is technically challenging. Because of their popularity and size, the design and traffic management decisions of these services also have a profound impact on the Internet infrastructure.