دانلود رایگان مقاله تاثیر مدل قدرت نقطه دسترسی در مدیریت LAN های بی سیم

Abstract

The reduction of the energy footprint of large and mid-sized IEEE 802.11 access networks is gaining momentum. When operating at the network management level, the availability of an accurate power model of the APs becomes of paramount importance, because different detail levels have a non-negligible impact on the performance of the optimisation algorithms. The literature is plentiful of AP power models, and choosing the right one is not an easy task. In this paper we report the outcome of a thorough study on the impact that various inflections of the AP power model have when minimising the energy consumption of the infrastructure side of an enterprise wireless LAN. Our study, performed on several network scenarios and for various device energy profiles, reveals that simple one- and two-component models can provide excellent results in practically all cases. Conversely, employing accurate and detailed power models rarely offers substantial advantages in terms of power reduction, but, on the other hand, makes the solving algorithms much slower to execute.

6. Discussion and conclusions

In the paper we have discussed the impact that the various elements of the AP power consumption model have when optimising the power efficiency of an enterprise wireless LAN. The performance of the models has been assessed for four classes of devices with different balance of the power components, deployed in homogeneous and heterogeneous networks, and for a variety of operational scenarios. From this extensive analysis, it emerged that: • The power consumption due to the traffic processing operation is fundamentally irrelevant. This has been mathematically proven for the homogeneous networks, whereas in the heterogeneous case the computational analysis revealed that its impact is well below the 1%. • In homogeneous networks, the simplest on/off power model is sufficient to provide very good results. Further but marginal energy gains can be achieved with the more sophisticated 2C and 3Cw models, but at the expense of much greater computational complexity. • In heterogeneous networks, the best compromise between energy efficiency and computational complexity is given by the 2C model, which includes the baseline and the airtime components. The fast-executing on/off power model could be regarded as a passable alternative only for heavily loaded networks or in cases with an evenly distributed traffic demand. Conversely, the complete 4C model might produce some energy benefits only for networks where the APs are very densely deployed (but with much longer solving times).