Many network-intensive applications in various science, engineering, and business domains require high bandwidths to support large-scale data transfer over long distances. Such bandwidth requirements give rise to the development and deployment of high-performance networks that are capable of provisioning dedicated channels with reserved bandwidths through circuit/lambda-switching or MPLS/GMPLS techniques. We consider both advance and immediate bandwidth reservations, the former reserving bandwidth ahead of time in a future time slot to provide guaranteed bandwidth, while the latter allocating bandwidth upon availability in the next immediate time slot. As a result, an ongoing data transfer task based on an immediate reservation may be preempted by the activation of an advance reservation due to the lack of bandwidth. We formulate the advance bandwidth scheduling problem to minimize the impact on immediate reservations. Based on rigorous statistical analysis of reservation dynamics, we propose a scheduling solution to route incoming advance reservations such that the number of preempted immediate reservations by the advance reservations is minimized. The performance superiority of the proposed scheduling solution is illustrated by extensive simulations in comparison with existing algorithms.