Critical Nodes Evaluation in Large-Scale Software Based on Static Structure and Runtime Information

Critical nodes of software systems are the nodes with the ability to transmit fault rapidly in the whole system. As a result, they have a significant impact on software reliability. To evaluate and identify the critical nodes, previous research focused on the static structure of software network which is inadequate since dynamic information affects the evaluation result as well. We propose a comprehensive method combining both static and dynamic information to evaluate critical nodes in our work. Static information consists of parameters measuring software structure. The importance of one node differs in different structures. In our evaluation model, we choose betweenness centrality to measure static structure because it can describe the importance of one node in static topological structure in complex network theory. For dynamic information, we focus on the execution frequency in specific software operation profile and user related operation. Combining the static and dynamic evaluating results, the comprehensive model is obtained. Using this evaluation model, we can obtain the critical nodes for one software system corresponding to different service states which indicate some sets of operating states. Protection strategy can be applied to these nodes pertinently to achieve efficient system reliability improvement.