Capturing the sensitivity of optical network quality metrics to its network interface parameters

Optical networks-on-chip (ONoCs) are gaining momentum as a way to improve energy consumption and bandwidth scalability in the next generation multicore and many-core systems. Although many valuable research works have investigated their properties, the vast majority of them lack an accurate exploration of the network interface architecture required to support optical communications on the silicon chip. The complexity of this architecture is especially critical for a specific kind of ONoCs: the wavelength-routed ones. These are capable of delivering contention-free all-to-all connectivity without the need for path reservation, unlike space-routed ONoCs. From a logical viewpoint, they can be considered as full nonblocking crossbars; thus, the control complexity is implemented at the network interfaces. To our knowledge, this paper proposes the first complete network interface architecture for wavelength-routed optical NoCs, by coping with the intricacy of networking issues such as flow control, buffering strategy, deadlock avoidance, serialization, and above all, their codesign in a complete architecture. The evaluation methodology spans from area and energy analysis via actual synthesis runs in 40-nm technology to RTL-equivalent (register-transfer level) SystemC modelling of the network architecture and aims at verifying whether the projected benefits of ONoCs versus their electrical counterparts are still preserved when the complexity of their network interface is considered in the analysis