There will be nearly three billion internet users and twice as many network-connected devices as people on the planet by 2015. Internet traffic will quadruple by then, driven mainly by online video, which will increase by seven times. Average global internet traffic will approach 250 terabytes a second, with a million minutes of video crossing the network every second. Peak internet traffic will be equivalent to 500 million people streaming online video simultaneously. The forecast figures are from the annual Visual Networking Index Forecast from Cisco, which has an interest in network growth. They are required reading for anyone involved in online video.

Online video will be the main reason for the increase in network traffic, available to around 1.5 billion users by 2015, up from more than a billion online video users in 2010. The number of online video users in China alone will pass half a billion.

Globally, 3 trillion minutes, or around 5 million years, of video media will cross the internet each month in 2015. The United Kingdom alone will see over 36,000 minutes of video streamed or downloaded every second, accounting for 70% of all consumer internet traffic.

Online video traffic will increase at a compound annual growth rate of 48%, from 8,079 petabytes a month in 2011 to 33,620 petabytes a month in 2015. Online video to the television will increase by a compound annual growth rate of 77%, from 838 petabytes a month in 2011 to 5,911 petabytes a month in 2015, accounting for 18% of online video traffic or 10% of all global consumer internet traffic.

The average fixed broadband connection will also be four times faster, delivering 28 megabits per second. The average internet user will generate nearly 25 gigabytes of traffic every month. Over 20 million households will generate half a terabyte per month.

The combination of an increasing number of devices, more internet users, faster broadband and more video usage will see total internet traffic approach a zettabyte a year by 2015, which is a trillion gigabytes.

The Cisco Visual Networking Index: Forecast and Methodology, 2010-2015 is available to download from the Cisco web site, which has useful interactive forecasting tools.