A quality of service based allocation and routing algorithm for distributed, heterogeneous real time systems

An increasing number of applications execute over a set of computing and communication resources and have end-to-end quality of service (QoS) requirements. Given a system and an application with specific flow structure and QoS requirements, this paper describes an integrated QoS-based allocation and routing algorithm that determines which computing and communication resources to utilize for this application. More specifically, the algorithm finds the best flow path for an application, subject to application flow and QoS constraints, so as to optimize system objectives (e.g., minimize total system utilization or balance the load). The paper also introduces a Δ-optimal algorithm that, relative to the optimal algorithm, significantly reduces the run-time of the algorithm with a minor degradation in the optimality of the solution. The Δ-optimal algorithm is guaranteed to produce a result that is at most Δ-units sub-optimal. The paper also analyzes the optimality and run time of the solution as a function of Δ for two multimedia scenarios. Rules of thumb for setting Δ are also given