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Contrary to popular thought and the overly-simplistic views of popular quality “benchmarks”, the Internet access provider is not the sole (or necessarily even the primary) influencer of subscribers’ Internet quality of experience. The quality of experience of an end-user for a given Internet-delivered application or content is affected by many choices made by many players through the value chain. This is the second in a series of blog posts, that explores those choices based on excerpts from Sandvine’s Global Internet Phenomena Spotlight: Exposing the Technical and Commercial Factors Underlying Internet Quality of Experience.
For the first blog post in the series, see:
How do you spend your lunch break?
For the first blog post in the series, see:Tough Choices: To HD or not HD
As I write this, its lunch time at Sandvine and some of my colleagues are foregoing food in favour of increased productivity, some are off at a yoga class, some have gone home to walk their dog(s), while others are eating at their desk and watching YouTube videos. To me, it’s this last group that is most interesting.
Below is a chart showing actual throughput (80th percentile) achieved by YouTube from a number of US Internet service providers (both Cable and DSL) for one week (all days overlaid) as collected in September 2013.
What is instantly noticeable in the chart is the fact that YouTube has two pronounced dips. The first may not surprise some as it occurs during the evening peak period when networks are most congested. The second dip however is far more interesting as it occurs over the lunch hour.
If we compare YouTube’s performance with Hulu (seen below) during the same time period and for the same set of operators we do not see a similar lunch hour dip. In fact there doesn’t appear to be a dip at all.
So why is YouTube suffering a noticeable drop in quality at two separate times in the day?
Many people immediately point to their ISP whenever their video buffers, or they experience another symptom of poor Internet quality. In this case however, because Hulu, another over-the-top video provider does not experience a noticeable dip in quality, and the data sample comes from multiple networks, we can rule out ISPs being the root cause of YouTube’s quality issue.
Instead, we can conclude that the root cause of the degradation in quality is likely occurring because of an oversubscription in the Google server farm (where YouTube is hosted) which makes YouTube unable to meet high lunch time and evening video demand. This oversubscription would result from a commercial decision by YouTube to regarding how much capital they wanted to invest in server capacity to maintain quality.
So the next time you try to watch a YouTube video and it buffers, don’t automatically blame your ISP. Google may very well have made a commercial decision that limits the ISPs ability to improve quality and caused the tens of thousands of users, like me, who would otherwise like to spend their lunch hour watching videos on YouTube, return to more productive activities. Like writing this blog.
For those interested in examining further, although not as widely publicized as Speedtest, YouTube has a ‘my_speed benchmark’ that unlike Speedtest which seeks to measure ‘absolute capacity’, seeks to measure ‘maximum demand’. You can use these benchmark tools to not only view your historical YouTube performance, but also measure in real-time the performance of a video you are viewing.
In the coming weeks we will continue take a deeper look at other key players in the Internet ecosystem and how the commercial and technical decisions that they make impact overall Internet quality. For those too eager to wait for our next post, you can download the Sandvine’s Global Internet Phenomena Spotlight: Exposing the Technical and Commercial Factors Underlying Internet Quality of Experience today.
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