More than two-thirds (67 percent) of all data centers will fully or partially adopt software-defined networking (SDN) by 2021, compared to just 16 percent in 2016, according to Cisco’s latest Cloud Index Report.

The findings show that by 2021, 94 percent of all workloads will be cloud-based, and global cloud traffic will represent 95 percent of total data center traffic.

The report also forecasts that SDN and network functions virtualization (NFV) will carry over half of “within data center traffic” — this is traffic that remains within the facility — over the same time period, compared to 28 percent in 2016.

Data center operators make money in one of two ways, said Shruti Jain, a senior analyst at Cisco. They can either offer more services to increase revenue. Or they can optimize operations to control costs.

“SDN and NFV will definitely help them control costs by making data center traffic more efficient,” Jain said.

While SDN and NFV architectures are more efficient and are better suited to cloud deployments — Cisco also forecasts global cloud data center traffic will reach 19.5 zettabytes (ZB) per year by 2021, up from 6 ZB per year in 2016 — there’s still a learning curve to mass adoption, Jain said.

“As with any technology, especially as it relates to data centers and cloud, there is always that period where businesses are trying it out, service providers are trying it out in terms of how much it is going to help them more efficiently deploy traffic and control cost before they turn their whole data center traffic onto SDN,” she explained. “But going forward, the forecast looks pretty good for SDN.”

Hyperscale data centers will drive this adoption, she added.

And, in fact, hyperscale data centers themselves will see growth surge over the forecast period. According to the report, these large-scale public cloud data centers will nearly double in number by 2021.

There were 338 hyperscale data centers globally in 2016, and 386 last year. By 2021, Cisco forecasts there will be 628 of these facilities around the world, representing a 1.9-fold growth over the forecast period.

Also by 2021, hyperscale data centers will support:

• Fifty-three percent of all data center servers (27 percent in 2016)
• Sixty-nine percent of all data center processing power (41 percent in 2016)
• Sixty-five percent of all data stored in data centers (51 percent in 2016)
• Fifty-five percent of all data center traffic (39 percent in 2016)

Hyperscale data center growth reflects the reality that enterprises are adopting hybrid- and multi-cloud business strategies, Jain said.

“We do see big growth happening in public cloud, but we do understand that a number of enterprises will continue to operate in the private cloud space, which is still owned and controlled by them,” she said. “As the trust in public data centers increase, as scalability and security concerns are addressed, we do see growth in adoption of these types of data center services by enterprises globally.”

The Cisco Cloud Index also finds software-as-a-service (SaaS) will remain the most popular cloud service model through 2021, as opposed to infrastructure-as-a-service (IaaS) and platform-as-a-service (PaaS).

By 2021, 75 percent (402 million) of the total cloud workloads and compute instances will be SaaS workloads and compute instances, up from 71 percent (141 million) in 2016.

Also by 2021, 16 percent (85 million) of the total cloud workloads and compute instances will be IaaS workloads and compute instances, down from 21 percent (42 million) in 2016. And 9 percent (46 million) of the total cloud workloads and compute instances will be PaaS workloads and compute instances, up from 8 percent (16 million) in 2016.