Multi-option, multi-class path scheduling methods for advance reservation systems

This work advances the state-of-art in path scheduling and route selection by considering multiple call classes and allowing users to provide multiple start-time options in their requests for bandwidth in advance-reservation systems. Our system model supports two call classes: User-Specified Start Times (USST) and Earliest-Start Time (EST). The USST class is suitable for applications such as remote visualization or 4K immersive video-conferencing, while the EST class is suitable for high-speed large file transfers. Two path-selection algorithms, Earliest Available Path (EAP) and Shortest Available Path (SAP), are considered. Given that most core network links are operated at low utilization to support failure-recovery, we focus our simulation study on low-load operation. At low loads, there is no significant difference in call-blocking rates between EAP and SAP, and therefore, we recommend choosing EAP to lower mean waiting time. Since file-transfers, unlike audio-video calls, do not have an intrinsic rate requirement, we studied the question of what rate to choose for EST calls, and found that if EST calls were assigned the full link capacity, call blocking rates and mean waiting times were higher than if EST calls were assigned half the link capacity. Finally, we studied inter-class effects, and recommend design choices that mitigate these effects.