In distributed real-time systems, both computation and communication are critical factors. The timeliness of activities relies on both the computation and the communication involved in them. Moreover, the timeliness of computation relies on that of communication, and vice versa. This property requires that both computation and communication be integrated into the resource allocation model and that the model be able to capture the interplay between them. Unfortunately, the utility/benefit/value accrual models employed in current distributed real-time systems are constructed solely on computation. They are inadequate for capturing the interplay between computation and communication. This paper extends previous research on utility-based model by proposing a new utility accrual model, which integrates both computation and communication. Most importantly, the interplay between computation and communication is fully characterized in the model. Under the new model, resource managers are guided towards maximizing system-wide utility by exploring the interplay between computation and communication instead of traditional meeting the timing constraint on computation and the deadline of communication separately. To validate the effectiveness of this model, a resource allocation algorithm called CAUASA is developed under it. The performance of CAUASA is compared to that of another resource allocation algorithm that is developed according to existing utility accrual models. Simulation results reveal that CAUASA is far superior to its counterpart. Therefore, the new utility accrual model provides a more effective framework for the resource allocation in distributed real-time systems.