A system comprising: - a lighting and/or environmental-control system comprising one or more lighting devices (1a, 1b, 1c) for emitting light and/or one or more environmental-control devices for providing an environmental-control function, and - a control device, for controlling the lighting and/or environmental-control system over a communication system which comprises one or more networks, the control device comprising: multiple transmitters (4a, 4b, 4c, 4d, 4e) each for transmitting to the lighting and/or environmental-control system via a different respective network interface (7a, 7b, 16, 17, 51) of the communication system; characterized in that the control device comprises further a controller configured to use each of a plurality of the transmitters to transmit an instance of a same control command to the lighting and/or environmental control system via each of a plurality of different paths, each of said instances of the same control command being for controlling the emitted light and/or the provided environmental-control function, and each of said paths comprising a different respective one of the network interfaces; wherein the lighting and/or environmental-control system is configured to invoke feedback to the control device for each instance of a control command which is received and/or executed; and wherein the controller is configured to receive feedback from the lighting and/or environmental control system, to compare the paths in dependence on the feedback, and based thereon to select which of the network interfaces to use to transmit subsequent control commands to the lighting and/or environmental-control system for controlling the emitted light and/or the provided environmental-control function. - a lighting and/or environmental-control system comprising one or more lighting devices (1a, 1b, 1c) for emitting light and/or one or more environmental-control devices for providing an environmental-control function, and - a control device, for controlling the lighting and/or environmental-control system over a communication system which comprises one or more networks, the control device comprising: multiple transmitters (4a, 4b, 4c, 4d, 4e) each for transmitting to the lighting and/or environmental-control system via a different respective network interface (7a, 7b, 16, 17, 51) of the communication system; the control device comprises further a controller configured to use each of a plurality of the transmitters to transmit an instance of a same control command to the lighting and/or environmental control system via each of a plurality of different paths, each of said instances of the same control command being for controlling the emitted light and/or the provided environmental-control function, and each of said paths comprising a different respective one of the network interfaces; wherein the lighting and/or environmental-control system is configured to invoke feedback to the control device for each instance of a control command which is received and/or executed; and wherein the controller is configured to receive feedback from the lighting and/or environmental control system, to compare the paths in dependence on the feedback, and based thereon to select which of the network interfaces to use to transmit subsequent control commands to the lighting and/or environmental-control system for controlling the emitted light and/or the provided environmental-control function.