Network equipment maker Cisco Systems Inc said global cloud data traffic will grow at a compound annual rate of 66 per cent between 2010 and 2015, as consumers and businesses seek untethered access to content and applications, Reuters reports. 

By mid-decade more than a third of all data center traffic will be based in the cloud, which allows data to be stored and accessed remotely, Cisco said in its first annual Global Cloud Index published on Tuesday.

Gobal data center traffic overall will increase four-fold, a 33 per cent compound annual growth rate between 2010 and 2015, according to Cisco.

That translates into data traffic of 4.8 zettabytes per year by 2015 or every man, woman and child watching a full length movie once a day for one year.

"What was surprising is how much data is actually being moved, we started off with a zettabyte," said Suraj Shetty, vice president of product and solutions marketing, referring to 2010 when annual data traffic worldwide was at 1.1 zettabyte, which equals a trillion gigabytes.

"The evolution of cloud services is driven in large part by users'' expectations to access applications and content anytime, from anywhere, over any network and with any device," Cisco said.

Economic considerations were also a significant factor, Shetty said, because cloud-based data centers could support more virtual machines and workloads than traditional data centers making remote storage more cost-efficient.

Cisco, which offers technology to build, deploy and use cloud services, expects that, by 2014, more than 50 per cent of all workloads will be processed in the cloud.

IT research firm Forrester has forecast the global cloud computing market will grow to $241 billion in 2020 from $41 billion this year.

However, it will still take some time and investments in network expansion until networks around the world are ready to handle advanced cloud services.

All regions can currently support some level of cloud services based on average download and upload speeds and the time it takes for information to pass through the network for business and consumer connections, Cisco said.

"However, few regions' average network characteristics are currently able to support the high-end advanced cloud apps," Cisco added.

Basic cloud applications include email, Web browsing or social networking, while advanced cloud services, which have higher network requirements, include advanced gaming and high definition video conferencing.

For the forecast Cisco collected network data from 10 enterprise and Internet data centers for 12 months.