Kerry Hinton

Green Cloud Computing: Balancing Energy in Processing, Storage, and Transport

Network-based cloud computing is rapidly expanding as an alternative to conventional office-based computing. As cloud computing becomes more widespread, the energy consumption of the network and computing resources that underpin the cloud will grow. This is happening at a time when there is increasing attention being paid to the need to manage energy consumption across the entire information and communications technology (ICT) sector. While data center energy use has received much attention recently, there has been less attention paid to the energy consumption of the transmission and switching networks that are key to connecting users to the cloud. In this paper, we present an analysis of energy consumption in cloud computing. The analysis considers both public and private clouds, and includes energy consumption in switching and transmission as well as data processing and data storage. We show that energy consumption in transport and switching can be a significant percentage of total energy consumption in cloud computing. Cloud computing can enable more energy-efficient use of computing power, especially when the computing tasks are of low intensity or infrequent. However, under some circumstances cloud computing can consume more energy than conventional computing where each user performs all computing on their own personal computer (PC).

Energy Consumption in Optical IP Networks

As community concerns about global energy consumption grow, the power consumption of the Internet is becoming an issue of increasing importance. In this paper, we present a network-based model of power consumption in optical IP networks and use this model to estimate the energy consumption of the Internet. The model includes the core, metro and edge, access and video distribution networks, and takes into account energy consumption in switching and transmission equipment. We include a number of access technologies, including digital subscriber line with ADSL2+, fiber to the home using passive optical networks, fiber to the node combined with very high-speed digital subscriber line and point-to-point optical systems. In addition to estimating the power consumption of todays Internet, we make predictions of power consumption in a future higher capacity Internet using estimates of improvements in efficiency in coming generations of network equipment. We estimate that the Internet currently consumes about 0.4% of electricity consumption in broadband-enabled countries. While the energy efficiency of network equipment will improve, and savings can be made by employing optical bypass and multicast, the power consumption of the Internet could approach 1% of electricity consumption as access rates increase. The energy consumption per bit of data on the Internet is around 75\bm muJ at low access rates and decreases to around 2-4 \bm muJ at an access rate of 100 Mb/s.

Evolution of WDM Optical IP Networks: A Cost and Energy Perspective

We review technologies and architectures for WDM optical IP networks from the viewpoint of capital expenditure and network energy consumption. We show how requirements of low cost and low energy consumption can influence the choice of switching technologies as well as the overall network architecture.

Energy Consumption of the Internet

As concerns about global energy consumption increase, the power consumption of the Internet is a matter of increasing importance. We present a network-based model that estimates Internet power consumption including the core, metro, and access networks.

Energy Consumption in Access Networks

We present a comparison of energy consumption of access networks. We consider passive optical networks, fiber to the node, point-to-point optical systems and WiMAX. Optical access technologies provide the most energy-efficient solutions.

Power consumption and energy efficiency in the internet

This article provides an overview of a network-based model of power consumption in Internet infrastructure. This model provides insight into how different parts of the Internet will contribute to network power as Internet access increase over time. The model shows that today the access network dominates the Internets power consumption and, as access speeds grow, the core network routers will dominate power consumption. The power consumption of data centers and content distribution networks is dominated by the power consumption of data storage for material that is infrequently downloaded and by the transport of the data for material that is frequently downloaded. Based on the model several strategies to improve the energy efficiency of the Internet are presented.

Energy consumption in wired and wireless access networks

Energy consumption is becoming an increasingly important issue throughout the community. For network operators in particular it is a concern as networks expand to deliver increasing traffic levels to increasing numbers of customers. The majority of the energy used by the Internet today is consumed in the access network, and this will continue to be the case for the short-to-mid- term future. Access technologies should thus be a prime focus for energy use mitigation. In this article, we present a detailed analysis of energy consumption in current and future access networks. We present the energy consumption of DSL, HFC networks, passive optical networks, fiber to the node, point-to-point optical systems, UMTS (W-CDMA), and WiMAX. Optical access networks are the most energy efficient of the available access technologies.

Photonic Switching and the Energy Bottleneck

The energy consumption of the Internet is growing exponentially. We examine the potential of photonic switching to reduce energy consumption by determining the contribution of cross connects and buffers to the total energy consumption of the Internet.

Switching Energy and Device Size Limits on Digital Photonic Signal Processing Technologies

The relationship between device size and power consumption of photonic signal processing devices is derived using device-specific models for photonic signal processing using semiconductor optical amplifiers, periodically poled lithium niobate, and highly nonlinear fibers. The results are then compared with the power-length characteristics of CMOS digital devices. The general conclusion is that photonic signal processing technologies demand significantly larger space and/or power than CMOS technologies.

Energy consumption in IP networks

A model of energy consumption in IP networks is used to estimate the energy consumption of the public Internet. Today’s Internet uses less than 1% of the available electricity supply. However, network energy consumption could grow substantially as access rates increase.