A cost-effective and energy-efficient all-optical access metro-ring integrated network architecture

All-optical access-metro networks avoid costly OEO conversions which results in subsequent reduction of infrastructure costs and improvement in energy-efficiency of the network. However, avoiding OEO conversions imply that OLTs are unable to route packets to the ONUs due to unavailability of processing provisions, which necessitates setting up of lightpaths between ONUs. Setting up lightpaths, require a control mechanism, which considers requests from all ONUs in the metro-ring and informs them about the lightpath to be set up. Owing to high data rate of optical networks, the lifetime of a lightpath may be minuscule (few microseconds), which enforces the control mechanism to perform these operations frequently, which incurs large control overhead and processing complexity. This turns out to be a major bottleneck in all existing proposals, which can be alleviated if lightpaths are set up between OLTs instead of ONUs. However, in this case, facilitating data transmission between source and destination ONUs becomes a challenge, due to inability of OLT to process and buffer data packets. In this paper, we resolve this issue by proposing a novel architecture which supports a plausible MAC protocol. The proposed architecture demonstrates significant reduction in cost and power-consumption figures with a slight improvement in reach when compared to traditional architectures.