De-blocking adaptive feedback control design for shared-buffer CIOQ switching architecture

Abstract

To address the issues of head-of-line (HOL) blocking at the virtual output queue (VOQ) level, packet loss, and congestion spreading caused by buffer overflow in the shared-buffer-based combined input and output queued (CIOQ) switching architecture, while enhancing its performance and stability, we propose a de-blocking adaptive feedback control (AFC) design in this study. The introduction of the credit timeout detection mechanism (CTDM) enables the CIOQ to achieve theoretical 100% non-blocking state, effectively eliminating the impact of HOL blocking. With the combined effect of the proposed VOQ dynamic regulation algorithm (VDRA) and threshold dynamic adaptive algorithm (TDAA), it can reduce the risk of congestion spreading caused by buffer overflow and consequently improve the overall performance of the system. Both theoretical analysis and experimental results demonstrate that, under typical traffic conditions, the proposed design achieves a maximum throughput of 1499.66 Gb/s and a minimum latency of 83 ns. Additionally, the effective throughput ratio reaches 96.94%, with a data link layer packet (DLLP) loss ratio of merely 0.61% and a packet loss rate as low as 0.6%. In comparison with traditional CIOQ and input queued (IQ) switch architectures, the proposed design demonstrates improvements in throughput by 15.12% and 20.55%, and forwarding latency is reduced by 26.9% and 54.7%, respectively, and the system stability is stronger, which can fully satisfy the demand for data exchange in complex situations.

Keywords

Shared-buffer CIOQ switching architecture / Head-of-line (HOL) blocking / Congestion spreading / Adaptive feedback control (AFC) / Peripheral component interconnect express (PCIe) interconnect protocol

RIGHTS & PERMISSIONS

The Authors. Published by Zhejiang University Press Co., Ltd.