Abstract: A data transmission method includes an access node sends first traffic to a first core network device in a core network through a first service plane of a bearer network. The access node sends second traffic to a second core network device in the core network through a second service plane of the bearer network. The first service plane and second service plane are independent all-active service planes in the bearer network. Service data sent by the base station is split on the access node, and split data each corresponds to one transmission path. Even if one transmission path is completely interrupted, the service data may still be transmitted by another core network device through the other transmission path.