Dynamic routing and resource assignment for multi-granular optical node architectures with optical grooming

As bandwidth demands continue to rise, wavelength-level granularity in wavelength division multiplexing (WDM)-based optical networks becomes a limiting factor, as scaling such networks places increasing load on the WDM nodes. This motivates a shift toward coarser switching granularities. Node architectures will thus evolve from wavelength switching to waveband-selective switching and eventually to fiber cross-connects as capacity requirements grow. Multi-granular optical node (MG-ON) architectures support this transition by integrating wavelength, waveband, and spatial switching. However, during dynamic routing and resource assignment, MG-ON architectures may suffer from inefficient utilization of wavelength, waveband, and spatial resources. This can lead to increased connection request blocking. To address this, we propose a dynamic routing and resource assignment algorithm combined with an augmented optical grooming strategy for MG-ON networks. We evaluate the proposed approach in terms of connection accommodation, switch count, and per-switch port requirements across multiple network configurations. Its performance is compared with baseline WDM networks and existing MG-ON grooming strategies.