Customized Routing and Sub-Timeslot Assignment for Deterministic Transport in FGU-Enabled Metro Converged Optical-Electrical Networks

Flexible Ethernet (FlexE) performs as an advanced technology in metro networks, offering bandwidth sharing, high resilience, and resource isolation advantages. Featured as the new brand of FlexE, fine granularity unit (FGU) has been recently proposed, where the standard 5 Gbps timeslot is further divided into 480 sub-ones for sub-1G service accommodation. However, this reduction in granularity will raise new issues on end-to-end (EtE) latency and jitter performance, which are crucial for emerging time-critical services, such as remote industrial control and virtual reality. With FGU, service data may experience extended wait time at forwarding sites due to the misalignment between data arrival and sub-timeslot readiness, thereby increasing the risk of violating latency and jitter requirements. Therefore, the FGU-enabled network cannot completely inherit the timeslot assignment scheme in traditional FlexE of solely bandwidth considerations. To address this issue, we propose a customized optical-electrical routing and sub-timeslot assignment scheme (CRTAS) for FGU, where latency and jitter requirements as well as service characteristics are considered. This scheme aims at minimizing the wait latency of sub-timeslot mapping and crossover in forwarding sites along the EtE path. Additionally, we also introduce the traditional sub-timeslot assignment scheme (TTAS) for comparison. Cases of virtual reality and industrial control are modelled and numerically evaluated, where CRTAS outperforms TTAS in terms of EtE latency and jitter guarantee. Our analyses can offer valuable insights for developing quality-of-service (QoS) committed transport solutions in future metro converged optical-electrical networks.