Network architectural is indispensable for a wide-area and robust Fiber-optic time transfer (FOTT) network, however, there is currently a deficiency in effective scheme. This article proposed a reconfigurable FOTT network architecture based on software-defined time transfer units (SD-TTU), enhancing the network’s capability for flexible resource allocation, automatic protection and restoration. The architecture consists of three layers: 1) time transfer layer for time signal transmission and clock difference cancellation; 2) monitor and control layer for monitoring network states, fault detection, and dynamic reconfiguration of the SD-TTU; and 3) service and configuration layer for customizable service construction and proactive network reconfiguration. A polymorphic software-defined time transfer unit (SD-TTU) is further designed, which can operate as a master station, intermediate station, and slave station using the same hardware. The proposed architecture and the designed SD-TTU are experimentally demonstrated over chained and ring networks, respectively. Network expansion, contraction, topology reconfiguration, failure and fault recovery are validated. The changes of measured mean clock differences are below 43-ps across different scenarios, verifying the robustness and flexibility of the proposed architecture.

Contrary to Optical Circuit Switching (OCS), Optical Burst Switching (OBS) is efficient for bursty traffic but also weak in guaranteeing the delivery of real-time traffic. We have proposed an OBS enhancement approach, called Labeled OBS with Home Circuits or LOBS-HC, which provides each source-destination pair with a wavelength sharable home circuit for the real-time traffic, so it can guarantee lossless transmission with a short delay. In previous works, we have shown that LOBS-HC requires less resources and provides a better QoS to the real-time traffic than OCS, since it does statistical multiplexing. Here, we extend the study of LOBS-HC. First, we study a few possible design choices in LOBS-HC. Then we evaluate its performance under not only real-time traffic, but also best-effort traffic. Finally, we analyze the effects of the switching speed and the burst size on the performance.