Networking giant’s latest Visual Networking Index predicts video to account for 82% of traffic.

Global IP traffic will triple between 2016 and 2021 to reach 3.3 zettabytes per year, according to Cisco’s 12th annual Visual Networking Index (VNI), published on Thursday.

That compares to 1.2 zettabytes – equivalent to 1.2 trillion gigabytes – in 2016, Cisco said.

A number of trends are expected to drive the increase, including growth in the number of Internet users, and the number of connected personal and machine-to-machine (M2M) devices. Ongoing adoption of online video and music streaming, and gaming, is also expected to drive traffic volume.

By 2021, Cisco expects the number of Internet users to reach 4.6 billion, up from 3.3 billion in 2016. Connected devices will increase from 17.1 billion to 27.1 billion, with M2M connections accounting for more than half of that total.

Unsurprisingly, video traffic will dominate, accounting for 80% of all Internet traffic by 2021, up from 67% in 2016.

"Globally, there will be nearly 1.9 billion Internet video users (excluding mobile-only) by 2021, up from 1.4 billion in 2016," Cisco said. By the end of the forecast period, the world will watch 3 trillion minutes of video per month.

In terms of fixed versus wireless, WiFi and mobile-connected devices will generate 73% of Internet traffic by 2021, compared to 27% for fixed. In 2016, that split stood at 62% wireless versus 38% fixed.

On a geographic basis, Cisco expects Asia-Pacific to account for the lion’s share of global IP traffic by 2021, generating 107.7 exabytes per month, ahead of North America with 85 exabytes per month.

Western Europe is expected to be the third-largest region, generating 37.4 exabytes per month, while Central Europe and Latin America are expected to generate 17.1 exabytes and 12.9 exabytes respectively per month. Finally, the Middle East and Africa are expected to generate 15.5 exabytes per month by 2021.