Flow rule sending method, path computation element, and path computation client

Embodiments of the present invention provide a flow rule sending method, a path computation element (PCE), a path computation client (PCC), and a system. The method comprises: a PCE generates a correspondence between path identification information and flow rules; and the PCE sends a path computation element communication protocol (PCEP) message to a PCC, the PCEP message carrying the correspondence between the path identification information and the flow rules, and the flow rules being used for instructing the PCC to forward a traffic matching the flow rules according to the path identification information. The PCE comprises: a processing unit, used for generating a correspondence between path identification information and flow rules; and a sending unit, used for sending a PCEP message to a PCC, the PCEP message carrying the correspondence between the path identification information and the flow rules, and the flow rules being used for instructing the PCC to forward a traffic matching the flow rules according to the path identification information. By means of the technical solution in the embodiments of the present invention, a traffic matching flow rules can be forwarded in time.