Simulation of replicated services in Jini

摘要

This paper presents a performance comparison of several assignment schemes for replicated services in Jim. Both early and delayed assignments have been used as basic options in our study. We also show that the quality of assignment decisions depends on the level of information detail available about the current state of the whole system. In our model the requests for service generated by the clients follow independent user- or machine-initiated transactions. Each client has to be assigned a service selected from the pool of available replicated services, which have joined the Jini federation and have registered with the lookup service. The assignment is transparent to the clients and is done in accordance with the applicable assignment scheme. The performance modeling of these schemes is based on queuing systems. The evaluation is done with regard to the mean residence time of the clients in the system as well as the control overhead imposed by the assignment schemes. The simulation results reveal the applicability, scalability and limitations of the assignment schemes for different relative load and granularity of the clients in a Jini federation.