In fact, cloud traffic will grow faster -- at a 35% compound annual growth rate -- than overall data center traffic (25% CAGR), according to this year's Cisco Global Cloud Index. By 2017, 69% of data center traffic will be cloud based, up from 46% in 2012.
For perspective on the big numbers in its study, Cisco said 7.7 zettabytes is equivalent to 107 trillion hours of streaming music -- about 1.5 years of continuous music streaming for the global population in 2017.
The growth in cloud-based traffic is largely due to the economies of scale that virtualization and cloud computing provides enterprises and service providers, Thomas Barnett Jr., director of service provider thought leadership at Cisco, said in an interview.
Due to ongoing privacy and security concerns businesses have with cloud-based applications, consumers are generating much more cloud traffic than businesses, he said. By 2017, consumers will generate 81% of cloud traffic compared to 19% by businesses, according to the report.
"Consumers are leading and driving the growth of cloud traffic," Barnett said, citing increased use of cloud storage services such as Google Drive, SkyDrive and Dropbox.
Still, cloud traffic generated by businesses will grow at a healthy clip -- 31% CAGR -- just behind the rate at which consumer-based cloud traffic will grow (35% CAGR), he said.
[Read about IBM's method for avoiding cloud performance problems by dynamically managing network bandwidth in "IBM Invention Aims To Fix Cloud Bottlenecks."]
North America generated the most cloud traffic last year, followed by Asia-Pacific, and that trend will continue into 2017, according to Cisco. However, the company expects the Middle East and Africa to have the highest cloud traffic growth rate.
Overall, most data center traffic -- 76% -- will remain in the data center, generated mostly by storage, production and development data, according to the study.
The report also included a forecast of "workload transition" in the data center, predicting that next year will be the first year that the majority of workloads will shift to the cloud at 51% compared to 49% handled in a traditional data center. By 2017, 63% of workloads will be processed in the cloud.
Increased virtualization in the data center is fueling a shift of workloads from traditional data centers to cloud data centers, according to Cisco. The company expects the growth of workloads in cloud data centers to be five times the growth of workloads in traditional data centers.
The Cisco Global Cloud Index also assessed "cloud readiness" around the world, based on characteristics of countries' fixed and mobile networks. All regions showed they can support an intermediate level of cloud services with their average fixed network performance, according to the study. Cisco described a download speed of 751-2,500kbps, an upload speed of 251-1,000kbps, and latency of 159-100 milliseconds as the network requirements for intermediate-level cloud services, such as ERP/CRM, video conferencing and music streaming.
This year saw an increase in the number of regions providing advanced cloud capability, Barnett said. Requirements for advanced cloud applications, as specified by Cisco, include a download speed of greater than 2,500kbps and upload speed of higher than 1,000kbps. In addition, the adoption of 4G is narrowing the gap between fixed and mobile networks, he said.
The Cisco Global Cloud Index is based on 40TB of data collected from 10 enterprise and service provider data centers, along with data on server shipments from market-research firms, which Cisco used to calculate an installed base of workloads by type and implementation. To calculate global cloud-readiness, Cisco used a separate study of more than 90 million speeds tests conducted from 150 countries.