A method includes receiving, by a forwarder, rule modification information sent by a controller. The rule modification information includes rule description match information and action instruction modification information. The rule description match information is used to determine a to-be-modified processing rule. Rule description information of the to-be-modified processing rule accords with the rule description match information, and the action instruction modification information is used to instruct to modify an action instruction specified in an instruction set of the to-be-modified processing rule. The method also includes modifying, by the forwarder, when the forwarder determines that rule description information of a first processing rule meets the rule description match information, an action instruction specified in an instruction set of the first processing rule according to the action instruction modification information.