A multi-class advance-reservation scheduler

High-speed dynamic virtual-circuit services, using multiprotocol label switching and advance-reservation schedulers, are being offered by several research-and-education network providers such as Internet2 and ESnet, and also by commercial providers. This paper develops and evaluates a multi-class batch scheduling algorithm for channels on a link across a reservation window of multiple timeslots. The scheduler runs an optimization algorithm to either admit a call and assign it a specific timeslot, or reject the call. The primary goal of the algorithm is to maximize link utilization, and a secondary goal is to minimize mean response time, while simultaneously considering call-blocking and response-time fairness across the different classes. Our evaluation showed that it is easier to achieve these multiple goals at higher loads. But recognizing that fairness often requires sacrificing mean response time, a tunable fairness relaxation parameter is included in the algorithm to allow operators flexibility in their service offerings.