Image: techinasia.com

Image: techinasia.com

If, like me, you often find that 1080p content on youtube buffers even when your download speed is more than sufficient to stream HD content, arsTechnica has the explanation.

Behind the scenes, in negotiations that almost never become public, the world’s biggest Internet providers and video services argue over how much one network should pay to connect to another. When these negotiations fail, users suffer. In other words, bad video performance is often caused not just by technology problems but also by business decisions made by the companies that control the Internet … 

The full piece is worth reading if you want to understand in detail, but the executive summary is this …

Bandwidth isn’t free. Every time a video is streamed, or a webpage accessed, someone has to pay for that traffic. The business model of the Internet is predicated on the idea that, overall, traffic balances out. Network A sends data to Network B, and Network B sends about the same amount of data back to Network A. Costs cancel out.

But that often isn’t the case for ISPs – the companies who deliver HD streaming video to your home while all you send in return are some emails and tweets. There are a number of ways of dealing with than imbalance. One way is for companies like Netflix and YouTube-owner Google to create local caches that reduce the amount of data that has to be transferred. Another is for payments to be made by companies delivering large volumes of data to the companies who receive and pass it on.

Those negotiations sometimes break down, and when they do, things can get messy.

In the most extreme cases, large Internet companies stop passing traffic to one another entirely. (This happened in 2005 with France Telecom and Cogent, in 2005 with Cogent and Level 3, and in 2008 with Sprint and Cogent.) But recent disputes have been less likely to lead to a complete severing of ties. […]

Instead, network operators can degrade traffic by failing to upgrade connections without severing them entirely. […] Degraded connections disproportionately affect the quality of streaming video because video requires far more bits than most other types of traffic. Netflix and YouTube alone account for nearly half of all Internet traffic to homes in North America during peak hours.

The solution may be found in a new proposal to ignore the direction of traffic, and simply to measure how much traffic is carried and over what distance. That approach makes the problem much easier to solve, argues the company behind the proposal, Internet backbone provider Level 3.

Two networks could still end up with unbalanced traffic under the bit miles approach, but it would be easier to fix. “If you connect in 10, 15, 20, 30 places, it’s easy to add connectivity points, it’s easy over time to add and subtract those connectivity points to make sure the networks are in balance and you incur equal costs of transmission,” Taylor said.

If accepted, the days of watching that light grey line stutter its way across the bottom of the YouTube video may soon be at an end.