Programmable Cycle-Specified Queue for Long-Distance Industrial Deterministic Packet Scheduling

TL;DR

This paper introduces a Programmable Cycle-Specified Queue (PCSQ) that enables microsecond-level resource reservation and jitter control for long-distance industrial deterministic networks, ensuring strict delay guarantees.

Contribution

The paper presents the first high-precision rotation dequeuing mechanism and cycle tags computation for active packet scheduling in industrial networks.

Findings

Schedules tens of thousands of time-sensitive flows

Guarantees millisecond-level delay

Achieves microsecond-level jitter control

Abstract

The time-critical industrial applications pose intense demands for enabling long-distance deterministic networks. However, previous priority-based and weight-based scheduling methods focus on probabilistically reducing average delay, which ignores strictly guaranteeing task-oriented on-time packet delivery with bounded worst-case delay and jitter. This paper proposes a new Programmable Cycle-Specified Queue (PCSQ) for long-distance industrial deterministic packet scheduling. By implementing the first high-precision rotation dequeuing, PCSQ enables microsecond-level time slot resource reservation (noted as T) and especially jitter control of up to 2T. Then, we propose the cycle tags computation to approximate cyclic scheduling algorithms, which allows packets to actively pick and lock their favorite queue in a sequence of nodes. Accordingly, PCSQ can precisely defer packets to any desired time. Further, the queue coordination and cycle mapping mechanisms are delicately designed to solve the cycle-queue mismatch problem. Evaluation results show that PCSQ can schedule tens of thousands of time-sensitive flows and strictly guarantee $ms$-level delay and us-level jitter.