Load sharing method, apparatus and system

Disclosed are a load sharing method, apparatus and system. The method comprises: a controller acquiring a load parameter of a target network device; the controller determining whether the target network device is in a load over-limit state according to the load parameter; and when the target network device is in the load over-limit state, the controller sending first configuration information to the target network device, wherein the first configuration information is used for configuring the target network device to be in a first state, and the first state instructs the target network device, when receiving an active discovery initiation (PADI) packet, to delay or not return an active discovery offer (PADO) packet. By means of the embodiments of the present invention, not only are loads of various network devices in a network more balanced, but also the realization of network load balancing has small difficulty and low costs.