Area Virtual Time

Abstract: We present a novel synchronisation algorithm for distributed discrete-event simulation (DDES), called the Area Virtual Time (AVT) algorithm. We first expose two orthogonal ideas of the synchronisation policy for DDES, which is either conservative or optimistic, and the time-keeping mechanism,which is based on either Local or Global Virtual Times. The AVT algorithm is based on a network of virtual time regions, which is a happy medium between the Local Virtual Time (LVT) and the Global Virtual Time (GVT). The AVT algorithm permits the different parts of the simulation model to run either under LVT or GVT time-keeping mechanisms. This is particularly suited to models which are less than homogeneous. In those cases, mapping the models entirely to either one of the time-keeping schemes would not be efficient; or, the real-time nature of the interfaces precludes the use of GVT in those parts of the model. Our results demonstrate that the AVT algorithm progresses the simulation times faster than either the LVT or the GVT schemes, and is less sensitive to variations in some key model and communication parameters -a desirable property in distributed computation.