No abstract

Abstract-Small or home office (SOHO) Ethernet LAN switches consume about 8 TWh per year in the U.S. alone. Despite normally low traffic load and numerous periods of idleness, these switches typically stay fully powered-on at all times. With the standardization of Energy Efficient Ethernet (EEE), Ethernet interfaces can be put into a Low Power Idle (LPI) mode during idle periods when there are no packets to transmit. This paper proposes and evaluates a new EEE policy of synchronous coalescing of packets in network hosts and edge routers. This policy provides extended idle periods for all ports of a LAN switch and thus enables energy savings deeper than in the Ethernet PHY only. We evaluate our method using an ns-2 simulation model of a LAN switch. We show that our method can reduce the overall energy use of a LAN switch by about 40%, while introducing limited and controlled effects on typical Internet traffic and TCP.

No abstract

Newer link-layer protocols -including Energy Efficient Ethernet (EEE) -support a sleep mode to save energy during idle periods. Bursting or coalescing of packets can be used to reduce the overhead from sleep-wake transitions for such links. We develop an energy-delay model for a coalescing queue given deterministic interarrival and service times. We also model the delay of a downstream queue. The model shows that there is a burst size beyond which only little energy savings can be achieved while the packet delay increases linearly. By a simulation study, we show that the results from our model approximate that of an EEE-enabled Ethernet link connected to an uplink.

An analytical model is developed for the recently proposed Dual-Mode Energy Efficient Ethernetan extension to EEE with two modes of low-power operation. The model can be used for predicting energy savings for different loads and other traffic parameters. The results from the analytical model closely match the results obtained by simulation for synthetic and real traffic.