Evaluating QoT-aware hybrid grooming schemes in dynamic C + L-band optical networks

As optical networks evolve toward dynamic, multi-band (C+L) architectures, efficient and QoT-aware
resource management becomes essential to ensure scalable and low-service downtime operation. This paper
introduces a novel, unified hybrid grooming framework that addresses the unique challenges of traffic
grooming in dynamic multi-band elastic optical networks (MB-EONs). Motivated by the need for costeffective
and adaptive high-capacity infrastructures, we propose a policy-based framework incorporating
three heuristic algorithms tailored to distinct optimization goals. The unique challenges of multi-band
optical networks, such as the non-uniform QoT performance caused by inter-channel stimulated Raman
scattering (ISRS) are explicitly considered in our design, as they directly impact grooming efficiency,
spectrum utilization, and achievable modulation formats. The algorithms include: (i) Min-Max Channel,
which minimizes spectrum fragmentation and reduces partial bit rate blocking probability by up to 35%;
(ii) Max Grooming Capacity, which improves line card interface (LCI) reuse and reduces deployment by
20%; and (iii) Time-Aware, which minimizes reconfiguration counts by up to 80%, significantly lowering
control overhead and service downtime. Unlike prior works limited to static or single-band scenarios,
our framework is the first to dynamically integrate routing, band selection, modulation format, grooming,
and spectrum assignment (RBMGSA) in a QoT-aware manner. Simulation results over NSFNET, Japan,
and Spain topologies under dynamic traffic conditions demonstrate that our approach supports flexible
trade-offs among performance, cost, and reconfiguration complexity. Notably, the reconfigurable variants of
our algorithms consistently outperform non-reconfigurable approaches by enhancing resource utilization
and reducing blocking. The proposed system also supports partial grooming, enabling improved service
accommodation and laying the groundwork for scalable and efficient operation in future multi-band
optical networks.