Using Simulations to Study the Efficiency of Update Control Protocols

Taking an existing large-scale realistic discrete event simulation model [1, 2] of a mobile distributed system with more than 700 000 units we investigate the efficiency of control protocols for the software and data updates of on-board-units (OBUs). Adding four different closed-loop control protocols to the existing simulation model we explain and investigate the technical implications of the control protocols: OBUs that allow incoming network connections can be reached at any time (Always-On or Sometimes-On). If the OBU is designed without a TCP/IP server, signaling is implemented either as polling (Sometimes-On with polling) or using a dedicated GSM signaling channel (On-Demand-On). The efficiency is discussed as a combination of metrics gathered during simulation runs and compared with the OBU controlled update logic. These simulation results are subsequently used as input for the system development process.