A method includes: A first network device receives a first subscription request sent by a first subscription device. The first subscription request includes an identifier of the first subscription device and an identifier of a destination device. The first network device obtains first subscription data based on the identifier of the first subscription device and the identifier of the destination device. The first subscription data includes an identifier of each path in N paths, N is greater than 1, and any path in the N paths is used to implement communication between the first subscription device and the destination device. The first network device sends a first subscription response to the first subscription device. The first subscription response includes the first subscription data.