Wake Transition Decision algorithm for energy saving in OBS network with LPI

The Low Power Idle (LPI) has been proposed by IEEE 802.3az Task Force to reduce energy consumption of network devices. Recently, many researches about the LPI have been progressing to maximize the sleep time and improve the performance of energy saving. However, most researches have not considered the effect of transition which causes additional energy consumption. The transition is a serious factor, which affect the performance of energy saving and QoS. Therefore, in this paper, we propose novel algorithms, called Wake Transition Decision(WTD) algorithms to reduce unnecessary transition in an OBS edge router with LPI. The Fixed Time based WTD algorithm(FT-WTD) reduces transition by waiting certain time before sleep transition. The Burst Length based WTD algorithm(BL-WTD) controls the unnecessary transition by keeping the active state of Tx module in an OBS edge router when burst length exceeds certain threshold. Simulation results show that not only approximately 30% of energy consumption can be decreased compared with exist LPI approach but also packet delay is kept within acceptable level by proposed algorithm.