Data flow redirection method and system, network device, and control device

A data flow redirection method to overcome a disadvantage that a quantity of adjustable data flows is relatively small due to limited space of a flow specification forwarding table. The method includes receiving, by a network device, a control message sent by a control device, where the control message carries redirection routing information of a data flow and a redirection routing indication, the redirection routing indication instructing to convert the redirection routing information of the data flow into a forwarding entry in a target forwarding table, and tablespace of the target forwarding table is greater than tablespace of a flow specification forwarding table of the network device, and converting, by the network device, the redirection routing information of the data flow into the forwarding entry in the target forwarding table according to the redirection routing indication.