The next frontier for communications networks: power management

International Journal of Network Management, 2005

The IT equipment comprising the Internet in the USA uses about $6 billion of electricity every year. Much of this electricity use is wasted on idle, but fully powered-up, desktop PCs and network links. We show how to recover a large portion of the wasted electricity with improved power management methods that are focused on network issues.

2010

In this paper we study the power consumption of networked devices in a large Campus network, focusing mainly on PC usage. We first define a methodology to monitor host power state, which we then apply to our Campus network. Results show that typically people refrain from turning off their PC during not-working hours so that more than 1500 PCs are always on, causing a large power waste. We then design PoliSave, a simple web-based architecture which allows users to schedule power state of their PCs, avoiding the frustration of wasting long power-down and bootstrap times of today PCs. By exploiting already available technologies like Wake-On-Lan, Hibernation and Web services, PoliSave reduces the average PC uptime from 15.9h to 9.7h during working days, generating an energy saving of 0.6kW/h per PC per day, or a saving of more than 250,000 Euros per year considering our Campus University. 9 J a n -0 0 J a n -0 1 J a n -0 2 J a n -0 3 J a n -0 4 J a n -0 5 J a n -0 6 J a n -0 7 J a n -0 8 25 50 75 100 125

In enterprise networks, idle desktop machines rarely sleep, because users and IT departments want them to be always accessible. While some solutions have been proposed, few of them have been implemented even more evaluated in real network environments. In this paper, we implement and evaluate a sleep proxy system, based on existing proposed architecture for this Proxy. This system is tested in 6 different PC machines of a real network. The results of the experiments show that machines can sleep almost 55% of the experimenting time (which is translated into energy savings) while maintaining their network accessibility to user satisfaction. However, there is a need of “cooperation” between IT procedures and sleep proxy system in order to gain better performance and thus less dissipated energy.

2009

Networked end-systems such as desktops and set-top boxes are often left powered-on, but idle, leading to wasted energy consumption. An alternative would be for these idle systems to enter low-power sleep modes. Unfortunately, today, a sleeping system sees degraded functionality: first, a sleeping device loses its network "presence" which is problematic to users and applications that expect to maintain access to a remote machine and, second, sleeping can prevent running tasks scheduled during times of low utilization (e.g., network backups). Various solutions to these problems have been proposed over the years including wake-on-lan (WoL) mechanisms that wake hosts when specific packets arrive, and the use of a proxy that handles idle-time traffic on behalf of a sleeping host. As of yet, however, an in-depth evaluation of the potential for energy savings, and the effectiveness of proposed solutions has not been carried out. To remedy this, in this paper, we collect data directly from 250 enterprise users on their end-host machines capturing network traffic patterns and user presence indicators. With this data, we answer several questions: what is the potential value of proxying or using magic packets? which protocols and applications require proxying? how comprehensive does proxying need to be for energy benefits to be compelling? and so on. We find that, although there is indeed much potential for energy savings, trivial approaches are not effective. We also find that achieving substantial savings requires a careful consideration of the tradeoffs between the proxy complexity and the idle-time functionality available to users, and that these tradeoffs vary with user environment. Based on our findings, we propose and evaluate a proxy architecture that exposes a minimal set of APIs to support different forms of idle-time behavior.

2008

Billions of dollars of electricity are being used to keep idle or unused network hosts fully powered-on only to maintain their network presence. We investigate how a Network Connectivity Proxy (NCP) could enable significant energy savings by allowing idle hosts to enter a low-power sleep state and still maintain full network presence. An NCP must handle ARP, ICMP, DHCP, and other low-level network presence tasks for a network host. An NCP must also be able to maintain TCP connections and UDP data flows and to respond to application messages. The focus of this paper is on how TCP connections can be kept alive during periods of host sleep by using a SOCKS-based approach called green SOCKS (gSOCKS) as part of an NCP. The gSOCKS includes awareness of the power state of a host. A prototype implementation of gSOCKS in a Linksys router shows that TCP connections can be preserved.

Future Generation Computer Systems, 2013

h i g h l i g h t s

2009

Over 500 million host computers, three billion PCs and mobile devices consume over a billion kilowatts of electricity. As part of this "system" computer networks consume an increasing amount of energy, and help reduce energy expenditure from other sources through E-Work, E-Commerce and E-Learning. Traditionally, network design seeks to minimise network cost and maximise quality of service (QoS). This paper examines some approaches for dynamically managing wired packet networks to minimise energy consumption while meeting users' QoS needs, by automatically turning link drivers and/or routers on/off in response to changes in network load.

2009

Over 500 million host computers, three billion PCs and mobile devices consume over a billion kilowatts of electricity. As part of this “system” computer networks consume an increasing amount of energy, and help reduce energy expenditure from other sources through E-Work, E-Commerce and E-Learning. Traditionally, network design seeks to minimise network cost and maximise quality of service (QoS). This paper examines some approaches for dynamically managing wired packet networks to minimise energy consumption while meeting users’ QoS needs, by automatically turning link drivers and/or routers on/off in response to changes in network load.

2011 Developments in E-systems Engineering, 2011

Many large enterprises are wasting vast amounts of electricity due to computers that are powered-up yet unused for considerable periods of time. It is unfortunate that although the facilities to power management are already available, many administrators are reluctant to adopt power saving features. This paper first highlights the scale of electricity wastage and goes on to consider the issues associated with computer power management before providing a detailed description of the development of a framework that can deliver power savings to large organisations The proposed framework effectively integrates standard network services, standard applications and off-the-shelf power management software together with policies and procedures to enforce power saving measures on individual computers.

IEEE Network, 2000

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 Internet's 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.