A distributed Automatic Power Optimization (APO) system and method are provided. The distributed APO system includes: one or more APO modules and a network management system. The one or more APO modules belong to one or more pre-divided APO links. Each APO module in the one or more APO modules belongs to only one APO link. The APO module is configured to, when the APO link to which the APO module belongs is triggered to perform power regulation, regulate a power attenuation or a gain between the two adjacent stations corresponding to the APO module and report a regulation result. The network management system is configured to, when learning that all of one or more APO modules in one APO link are successful in regulation, if there is a next APO link of the APO link, trigger the next APO link of the APO link to perform power regulation.

A first Broadcast-and-Select (B&S) node includes a first downstream port coupled to a first downstream power splitter/combiner, a second downstream port coupled to a second downstream power splitter/combiner, and a third downstream port coupled to a third downstream power splitter/combiner. The first downstream power splitter/combiner is configured to split a total power of a first downstream optical signal received at the first downstream port to form a first version and a second version of the first downstream optical signal, the second power splitter/combiner is configured to: receive the first version of the first downstream optical signal, and transmit the first version of the first downstream optical signal to a first network node via the second downstream port, the third downstream power splitter/combiner is configured to: receive the second version of the first downstream optical signal.

Information on allocation of a bandwidth of uplink communication of each user device is extracted from information notified by an upper-level device on the uplink communication of the user devices. Identification information of a lower-level device connected to a terminal device and identification information of the user devices are stored in correlation with each other. A bandwidth demanded for uplink communication of the terminal device is determined on the basis of the information on the allocation of the bandwidth of the uplink communication of each of the user devices and the identification information of the user devices. A start time point of the uplink communication of the terminal device and the amount of information of signals for which transmission of the uplink communication of the terminal device is allowed are allocated to the terminal device on the basis of the bandwidth demanded for the uplink communication of the terminal device.

Data center network architectures, systems, and methods that can reduce the cost and complexity of data center networks. Such data center network architectures, systems, and methods employ physical optical ring network and multi-dimensional network topologies and optical nodes to efficiently allocate bandwidth within the data center networks, while reducing the physical interconnectivity requirements of the data center networks. The respective optical nodes can be configured to provide various switching topologies, including, but not limited to, chordal ring switching topologies and multi-dimensional chordal ring switching topologies.

A method for determining a bitrate allocation of a plurality of optical channels in an optical transmission link with discretized channel bitrates, the method comprising determining an initial discretized bitrate allocation and a corresponding initial power allocation for the plurality of optical channels for supporting the initial discretized bitrate allocation with the proviso that all optical channels meet a pre-defined optical signal-to-noise, OSNR, threshold for the respective initial discretized bitrate allocated to the respective optical channel; starting from the initial power allocation, varying, for an investigated optical channel of the plurality of optical channels, a channel power of the investigated optical channel to estimate a highest supported discretized bitrate for the investigated optical channel, wherein the highest supported discretized bitrate is the highest discretized bitrate for which the investigated optical channel meets a corresponding OSNR threshold; including the investigated optical channel in an upgrade candidate subset of the plurality of optical channels for potential bitrate upgrades based on the highest supported discretized bitrate exceeding the initial discretized bitrate for the investigated optical channel; and providing the upgrade candidate subset to an upgrade allocation algorithm.