Previous analysis and industry focus has missed the point: access networks, not data centres, are the biggest threat to the sustainability of cloud services. This is because more people are accessing cloud services via wireless networks. These networks are inherently energy inefficient and a disproportionate contributor to cloud energy consumption.
Cloud computing has rapidly emerged as the driving trend in global Internet services. It is being promoted as a green technology that can significantly reduce energy consumption by centralising the computing power of organisations that manage large IT systems and devices. The substantial energy savings available to organisations moving their ICT services into the cloud has been the subject of several recent white papers.
Another trend that continues unabated is the take-up and use of personal wireless communications devices. These include mobile phones, wireless-enabled laptops, smartphones and tablets. In fact, tablets don’t accommodate a traditional cable connection; rather it is assumed a local or mobile wireless connection will be used to support all data transferred to and from the device. There is a significant emerging convergence between cloud computing and wireless communication, providing consumers with access to a vast array of cloud applications and services with the convenience of anywhere, anytime, any network functionality from the device of their choice. These are services many of us use every day like Google Apps, Office 365, Amazon Web Services (AWS), Facebook, Zoho cloud office suite, and many more.
To date, discussion about the energy efficiency of cloud services has focussed on data centres, the facilities used to store and serve the massive amounts of data underpinning these services. The substantial energy consumption of data centres is undeniable and has been the subject of recent high-profile reports including the Greenpeace report, How Clean is Your Cloud.
However, focussing cloud efficiency debate on data centres alone obscures a more significant and complex problem and avoids the critical issue of inefficiency in the wireless access network Data centres are only part of a much larger cloud-computing ecosystem. In fact, as this white paper puts forward, the network itself, and specifically the final link between telecommunications infrastructure and user device is by far the dominant and most concerning drain on energy in the entire cloud system.
Based on current trends, wireless access technologies such as WiFi (utilising fibre and copper wireline infrastructure) and 4G LTE (cellular technology) will soon be the dominant methods for accessing cloud services. ‘Wireless cloud’ is a surging sector with implications that cannot be ignored. Our energy calculations show that by 2015, wireless cloud will consume up to 43 TWh, compared to only 9.2 TWh in 2012, an increase of 460%. This is an increase in carbon footprint from 6 megatonnes of CO2 in 2012 to up to 30 megatonnes of CO2 in 2015, the equivalent of adding 4.9 million cars to the roads. Up to 90% of this consumption is attributable to wireless access network technologies, data centres account for only 9%.
Curbing the user convenience provided by wireless access seems unlikely and therefor the ICT sector faces a major challenge. Finding solutions to the ‘dirty cloud’ at the very least requires a broader acknowledgment of the cloud computing ecosystem and each components’ energy requirements. There needs to be a focus on making access technologies more efficient and potentially a reworking of how the industry manages data and designs the entire global network.
This white paper sets out to establish a starting point for addressing these issues, presenting a detailed model that estimates the energy consumption of wireless cloud services in 2015 taking into account all of the components required to deliver those services.The authors conclude -
Cloud computing is widely viewed as the next major evolutionary step for the Internet and Internet-based services. The shift to wireless access is also continuing at a great rate. Cisco projects that cloud computing will represent approximately 34% of data centre traffic in 2015 , with approximately 20% of data centre traffic will be served by wireless access networks.
Wireless and cloud are converging trends supported by the increased availability of affordable, powerful portable devices, convenient and useful applications, and highspeed wireless broadband infrastructure. This convergence is expected to be a key driver of traffic growth on telecommunications networks in the future.
There is evidence to show that cloud services access via fixed-line networks could result in lower energy consumption relative to current computing arrangements, such as replacing powerful desktop computers with cloud services [9,10,11]. Greenpeace has highlighted the carbon footprint of cloud computing but focused on data centres as being the biggest contributor to energy consumption. When considering the energy consumption of the wireless cloud, all aspects of the cloud ecosystem must be taken into account, including end-user devices, broadband access technology, metro and core networks, as well as data centres.
This white paper analysed the various components of the wireless cloud ecosystem to identify the dominant energy consumers. The CEET model explored the impact of the wireless cloud, accounting for all aspects of the ecosystem including devices, broadband access technology, and metro and core telecommunications, in addition to data centres. The predicted large-scale take-up of wireless cloud services will consume 32 to 43 TWh by 2015. The energy consumption of wireless access dominates data centre consumption by a significant margin.
To ensure the energy sustainability of future wireless cloud services, there needs to be a strong focus on the part of the ecosystem that consumes the most energy: wireless access networks. Further debate needs to move beyond the data centre to develop a holistic account of the ecosystem with this white paper being a step in that direction.