A control apparatus of a communication system that uses a plurality of communication paths from a transmission node to a reception node to redundantly transmit data is provided. The apparatus comprises: a setting unit for setting priorities to a plurality of partial data; a calculation unit for calculating the time slot number which is required to transmit the partial data on the communication paths; a selection unit for selecting one or more combinations of the partial data and the communication path. The selection unit selects the one or more combinations in descending order of the priorities of the partial data and selects the one or more combinations in ascending order of the required time slot number if the priorities of the partial data are equal.