Experience of responsiveness verification for connection establishment protocols

The responsiveness verification of a given communication protocol is to check whether the given protocol can recover from any abnormal state to a normal state within a permissible time or not. In order to make practical discussions, we assume that the lower and upper bounds of execution time are given for each message transfer and event. We propose a new responsiveness verification method which executes several events concurrently based on residual times of events, and develop a simulator which implements the proposed method. Then we present an experience which applies the simulator to the design of an actual connection establishment protocol for a certain plant control system. The system adopts the client server model and real time constraints exist on connection establishments. In the experience, we first specify the protocol straightforwardly. Then we apply the simulator to the specification and detect design faults against responsiveness. Next, we revise the specification successfully based on the state sequences generated by the simulator. The results of the experience conclude that the proposed method is effective for the case study.