Trading off Energy and Forwarding Performance in Next-Generation Network Devices

Description

The concept of energy-efficient networking has begun to spread in the past few years, gaining increasing popularity. Besides the widespread sensitivity to ecological issues, such interest also stems from economic needs, since both energy costs and electrical requirements of telcos' and Internet Service Providers' (ISPs) infrastructures around the world show a continuously growing trend. In this respect, a common opinion among networking researchers is that the sole introduction of low consumption silicon technologies may not be enough to effectively curb energy requirements. Thus, for boosting the network energy efficiency, these hardware enhancements must be integrated with mechanisms able to adapt the network device resources to the current offered load. The chapter is organized as follows. At first, we explore current perspectives in power consumption for next generation networks. Secondly, we will try to identify and to characterize the main sources of energy consumption in a heterogeneous set of wire-line network devices. Then, we will move our attention to analysing and evaluating the impact of power scaling on next-generation network devices focusing on two basic power scaling techniques: Adaptive Rate (AR) and Low Power Idle (LPI). We will introduce a simple analytical model based on classical concepts of queuing theory able to capture the trade-off between energy- and network-aware performance metrics, when AR and/or LPI techniques are adopted in a network device. Finally, in order to validate the proposed model, we discuss the results of several tests performed by using real-world traffic traces, and compare the estimated performance indexes with experimental measurements, obtained with Component Off-The-Shelf (COTS) SW routers.

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