High-performance networks have been increasingly deployed to provision dedicated channels for large data transfers over long distances to support various network-intensive applications with promised Quality of Service in terms of bandwidth and delay. These networks are generally capable of both advance and immediate bandwidth reservations, the former reserving resources ahead of time in a future time slot, while the latter allocating resources upon availability in the next immediate time slot. At the activation of an advance reservation typically with a higher priority, some ongoing data transfer tasks based on immediate reservations may be preempted due to the lack of resources. We propose a comprehensive bandwidth reservation solution to optimize network resource utilization by exploring the interactions between advance and immediate reservations. This solution integrates two major interrelated components: (i) a scheduling algorithm based on statistical analysis of reservation dynamics to route incoming advance reservations with both bandwidth and delay constraints for minimal impact on ongoing immediate reservations, (ii) a runtime preemption scheme to minimize the actual number of immediate reservations that must be preempted at the activation of an advance reservation. Extensive simulation results show that the proposed reservation solution exhibits a superior performance over existing methods.