The event service is the earliest CORBA solution to the message queue model of communication in distributed systems. Typical implementations, however, suffer from the lack of event delivery guarantees. The loss of messages is aggravated by the presence of burstiness in the input to the event service, and occurrences of isolated bursts of traffic could also have serious effects. In this paper, we develop stochastic reward net (SRN) models that can aid in the study and configuration of the event service to conform to design specifications. To capture burstiness in the input, a Markov-modulated Poisson process (MMPP) is used as the input source. Erlang distributed event consumption times are used in the models to accommodate more general distributions and a wider range of variances. The models also take into consideration the FIFO discard policy adopted in many event service implementations. The SRN models are solved using the tool SPNP (Stochastic Petri Net Package). The applicability of the models to the CORBA notification service is also briefly discussed.
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