A forwarding unit for a SDN system is provided, the forwarding unit being configured to forward data packets and comprising a memory module for storing at least one forwarding rule and a forwarding rule managing module, wherein the forwarding rule managing module is configured to activate the at least one forwarding rule according to a preset time condition and wherein the preset time condition comprises at least two activation times of the at least one forwarding rule and wherein the forwarding rule managing module is configured to activate the at least one forwarding rule at any one of the at least two activation times.