EU project solves the mystery of Netflix’s content delivery network

With online video content currently accounting for half of web traffic and rich content applications sprouting everywhere, the team’s findings - which notably reveal that Netflix’s content delivery network (CDN) spans 233 sites across six continents - are crucial. They hint at how Internet infrastructure will evolve to address future capacity issues, expose the diversity of the Internet ecosystem worldwide, and suggest that the specifics of each region’s ecosystem and market should lead to different development strategies.

Different location, different strategy

In April and May 2016, the five-researcher team from Queen Mary, University of London (QMUL) requested videos from university computers, localising the requests using a browser extension. They studied the traffic delivered by the servers in each region, eventually highlighting the relative reliance on Internet eXchange Points (IXPs) and Internet Service Providers’ (ISPs) servers.

Their findings revealed significant differences in Netflix’s network between countries and continents: whilst in North America Netflix is present in many locations simultaneously, in Europe, their servers are deployed at only a few locations per country. The UK comes out as a notable exception to that rule, as the situation there is more similar to that of North America.

When studying these differences, the team noticed that IXP locations tend to rely on significant number of servers at few locations, whilst ISP deployments are smaller in size but often at many locations. They also found that the sheer size of the deployments reflected the various markets of Netflix quite well.

‘The study is important as it provides an insight into how today’s Internet works,’ said Timm Boettger, first author of the study supported by the EU-funded ENDEAVOUR project. ‘The different deployment strategies observed are caused by inherent regional differences, forcing Netflix to adapt its strategy to ensure low movie start-up times and to avoid video stalling during playback. These differences are not only caused by how well an ISP [Internet service provider] connects its end-users, but also by how well different intermediary networks and ISPs interconnect and exchange traffic.’

Moving ahead

‘This study highlights the importance of the still vastly underappreciated IXP ecosystem,’ said Professor Steve Uhlig, senior supervisor of the team and Principal Investigator of the Horizon 2020-funded project. ‘Indeed, IXPs are vital to supporting high-speed connectivity in the Internet, especially for large content delivery players such as Netflix. This study supports the need to carry out more research relevant for IXPs, as done within the ENDEAVOUR project.’

For the ENDEAVOUR team, a better understanding of IXPs is key to reaching the project’s core objective: enabling added-value services to be provided thanks to Software-Defined Networking (SDN), on top of Internet Exchange Points and other network interconnection fabrics. They have until December 2017 to do so, when the project is due to finish.

The project’s study of Netflix, titled ‘Open Connect Everywhere: A Glimpse at the Internet Ecosystem through the Lens of the Netflix CDN,’ is available on the ArXiv website.

For more information please see:
project website