High-performance system design for a large-scale AWG-based WDM star network

Single-hop arrayed waveguide grating (AWG)-based wavelength division multiplexing (WDM) networks have attracted considerable attention in next-generation networks, especially due to their capability to support a large number of nodes within metropolitan areas. However, due to the static-wavelength-routing properties (non-broadcast nature) of AWG equipment, multiple copies of control information in the reservation-based medium access control (MAC) scheme must be sent to all output ports of the AWG device. Consequently, the control overhead becomes more severe, especially for large-scale networks such as data center networks. In this paper, we propose an AWG-node-connection network architecture that is capable of dividing all nodes into $D$ self-competition subgroups using a ${D \times D}$ AWG device at the center of a star network. By employing this grouping approach, our scheme reduces the control overhead to ${1/D}$ of the previous conventional method, thereby significantly improving system performance. We further propose an MAC protocol that aims to resolve the contention among the nodes attached to different input–output ports of the AWG, maximize spatial reuse, ensure point-to-point transmission, and, importantly, enhance system throughput. Furthermore, our proposed scheme features a simple topology and straightforward hardware, making it suitable for large-scale networks such as data center networks. The simulation and analytic results demonstrate that, as the number of nodes increases, the proposed MAC scheme achieves exceptional system performance under a wide range of traffic loads and various system parameters.