Data aggregation is a key problem in wireless sen- sor networks due to both energy-constrained and bandwidth- constrained. In this paper, we highlight the aggregation benefits in network layer and MAC layer by modeling the energy consumption for some energy-efficient routing protocols and MAC protocols. Besides, we define two parameters, aggregation ratio w and packet size coefficient λ, to evaluate the efficiency of an aggregation method, and we discuss their trade-off. Additionally, we propose comparison between A-ARMA and compressive sensing, which are on behalf of the state-of- the-art forecasting aggregation and compressing aggregation respectively.