Power Awareness in Network Design and Routing

Exponential bandwidth scaling has been a fundamental driver of the growth and popularity of the Internet. However, increases in bandwidth have been accompanied by increases in power consumption, and despite sustained system design efforts to address power demand, significant technological challenges remain that threaten to slow future bandwidth growth. In this paper we describe the power and associated heat management challenges in today's routers. We advocate a broad approach to addressing this problem that includes making power-awareness a primary objective in the design and configuration of networks, and in the design and implementation of network protocols. We support our arguments by providing a case study of power demands of two standard router platforms that enables us to create a generic model for router power consumption. We apply this model in a set of target network configurations and use mixed integer optimization techniques to investigate power consumption, performance and robustness in static network design and in dynamic routing. Our results indicate the potential for significant power savings in operational networks by including power-awareness.

I. Introduction

In the last decade, the Internet transformed from a computer network used primarily by academics into a worldwide communication medium with significant impact on the global economy. The role of the Internet will perhaps be even more important in the future, prompting Ray Ozzie, Microsoft's CTO to recently state that “ We're in a new era—an era in which the Internet is at the center” [1]. The tremendous growth in the number of end users and their network connection speeds has resulted in a consistent, exponential increase in the bandwidth demand. To keep pace, Internet Service Providers have relied on similar growth in bandwidth and capacities of routers and switches. These performance improvements have been accompanied by a decrease in the cost per byte of traffic, which has further fueled the growth of the Internet by making connectivity more affordable for everyone.