Publisher Summary This chapter focuses on the main techniques that have been developed to date for use in low power network systems. It presents the main techniques for low power lookup engines and low power network processors. Power consumption constitutes a significant issue in the emerging green computing environment. Network systems are special-purpose embedded computing systems. The power consumption of most network systems is constrained by their deployment environments. Many network systems are installed in densely utilized equipment racks. Limits on cooling of this equipment put a bound on how much energy can be consumed (and dissipated as heat). Some network systems are used in handheld, battery-operated systems or in application areas that require battery-operated, and thus power-limited, systems. The current state of the art of low power embedded system design does not enable the development of systematic approaches for power efficient systems overall; importantly, several results are developed for embedded subsystems, such as processors and sensors. For network systems, the major effort to date has been on the most power-consuming system components.