In conventional DEA models, decision making units (DMUs) are generally assumed as a black-box while the performance of decision making sub-units (DMSUs) and their importance play crucial roles in  analyzing the performance of systems which have internal processes. The present paper introduces an ideal network which have efficient processes and next purposes a new approach for evaluating importance of network components (DMSUs) based on comparison with the ideal network. Eventually, overall efficiency of network system will be determined which can be decomposed to the weighted efficiency of its sub-processes. As the result of the purposed approach, we can determine the situations that the network would perform better by improving the efficiency of the important DMSUs which have a vital impact on network performance.