vPIFO: Virtualized Packet Scheduler for Programmable Hierarchical Scheduling in High-Speed Networks

Programmable packet scheduling enables the integration of scheduling algorithms into switches without the need for hardware redesign. The Push-In First-Out (PIFO) queue facilitates a programmable packet scheduler, supporting a single scheduling algorithm flexibly. However, hierarchical scheduling required in Multi-Tenant Data Centers (MTDCs) remains non-programmable. Dynamic and diverse hierarchical scheduling algorithms necessitate alterations in both the number of PIFO queues and their connection topology, posing a significant challenge to support them on fixed hardware.