Adaptive Flow Control Mechanism for Optical Switching Data Center Networks

This is the authors' abstract. We don't add key points for this paper.

Optical switching is anticipated to be an alternative to electrical switching in Data Center Networks (DCNs), as it can provide higher bandwidth at a relatively lower cost and energy consumption. However, deploying optical switching systems remains a significant challenge due to the lack of an adaptive flow control (FC) mechanism to provide elastic bandwidth to cope with traffic bursty and complexity. Implementing adaptive FC requires addressing two important technical challenges, including high-precision time synchronization among network nodes and low-latency scheduling for dynamic time-slot allocation. We have designed a high-precision time synchronization mechanism that enables nanosecond rapid optical switching control. Additionally, we proposed a low-latency scheduling strategy to facilitate the dynamic time-slot allocation while effectively eliminating packet contention. Experimental results demonstrate that the proposed adaptive FC mechanism has achieved zero packet loss and zero packet error rates across various bursty traffic patterns, significantly outperforming the fixed time-slot method with a packet loss rate of 61.2%. Additionally, the system has achieved a very low synchronization offset of 1.65 ns, an extremely low timer jitter (σ = 11.06 ps), and no observed drift during long-term operations. Furthermore, the proposed scheduling mechanism in our system completely avoids optical packet contention and reduces control time to 30.72 ns, representing a tenfold reduction compared to the typical ‘Request-Grant’ (350.72 ns) approach.