A control network comprises multiple master nodes and multiple slave nodes, connected together in a loop configuration by at least one fiber optic cable. The master nodes share concurrent control over the network nodes by time multiplexing or other techniques. The control network may include two fiber optic rings which carry the same data simultaneously in opposite directions around the loop. A polling scheme may be used by the master nodes such that only one node transmits at a given time in both directions around the loop. The receiving node(s) propagate the transmissions and select between the transmissions based on time, error rate, or other factors. A hierarchical control network may be constructed with upper tier and lower tier fiber optic rings. Multiple master nodes may be used at any level of the ring, and some or all of the rings may include two fiber optics for bidirectional, redundant communication within the network.