QoS as middleware: bandwidth reservation system design

We wish to provide quality of service (QoS) to scientists who are remotely controlling experiments on singular instruments such as the LBL Advanced Light Source (ALS) or who need to harness heterogeneous and distributed computing resources to perform large-scale computation. To ensure the timely availability of the computing, storage, and networking resources required for data collection and/or analysis, use of these resources must be scheduled in advance. The bandwidth reservation system (BRS) reserves time in IP differentiated service classes (S. Blake et al.). These classes have upper bounds on the total bandwidth allocation. The reservation unit is a slot: a well-defined period of time with an associated bandwidth. The sum of the allocated bandwidths in all of the slot allocations never exceeds the maximum bandwidth defined for the service class. The result is that the classes are never oversubscribed.