中文摘要：

内容分发网络是一种新型的网络构建方式，能为用户提供较好的网络访问速度和稳定性，但其复杂的网络设备使得能耗相对较大，因此，内容分发网络的节能及能耗评价是其重要的研究主题。针对内容分发网络的网络结构，提出一种睡眠-唤醒机制和动态速率调节机制相结合的内容分发网络节能策略，并运用随机Petri网对内容分发网络节能策略进行能耗分析。在随机Petri网建模的基础上应用模型化简和评价方法，通过分析随机Petri网模型各状态稳定概率得到系统平均能耗，并使用软件SPNP对节能机制加入前后的内容分发网络能耗进行对比分析。通过对比分析表明，该节能策略能很好地降低内容分发网络的平均能耗。

英文摘要：

Content distribution network （CDN） is a new network construction way, and can provide better network access speed and stability for network users. However its complicated network facilities cause more energy consumption. Therefore, he energy saving and energy consumption evaluation of CDN is an important research topic. In this paper, we propose an energy-saving strategy for CDN, which combines the sleep-awake mechanism with dynamic rate regulation mechanism; and then we analyse and evaluate this energy-saving mechanism based on stochastic Petri nets. We set up the stochastic Petri nets model of energy-saving mechanism and apply model reduction and evaluation method to solve it. We analyse stable probability of various states in stochastic Petri nets model to get system average energy consumption, and use the software SPNP to carry out comparative analyses on energy consumption of CDN before and after the energy-saving mechanism is taken. It is demonstrated by ihe comparative analyses that this energy conservation strategy can reduce the average energy consumption in CDN.