Communication Method, Device, And System

A communication method, wherein the method comprises:

• obtaining, by a first network element, a first cell identifier and a network identifier, wherein the network identifier comprises an identifier of a first private network and an identifier of a second private network, and wherein the first network element serves a terminal device in the first private network;
• determining, by the first network element based on the first cell identifier, that an area in which the terminal device is currently located is beyond a service range of a cell identified by the first cell identifier;
• and
• sending, by the first network element, the first cell identifier and the network identifier to a first mobility management network element, wherein the first cell identifier and the network identifier are used to obtain downlink routing information, and wherein the downlink routing information is used to indicate transmission of downlink data from a first user plane entity in the first private network to a second user plane entity in the second private network.

A communication device, comprising:

• a transceiver;
• at least one processor;
• and
• one or more memories coupled to the at least one processor and storing programming instructions for execution by the at least one processor to:
• receive, by the transceiver, a first cell identifier and a network identifier from a first network element, wherein the network identifier comprises an identifier of a first private network and an identifier of a second private network;
• obtain information about a second network element based on the first cell identifier and the network identifier, wherein the first network element serves a terminal device in the first private network, and wherein the second network element serves the terminal device in the second private network;
• and
• send, by the transceiver, the first cell identifier and the network identifier to the second network element indicated by the information about the second network element, wherein the first cell identifier and the network identifier are used to obtain downlink routing information, and wherein the downlink routing information is used to indicate transmission of downlink data from a first user plane entity in the first private network to a second user plane entity in the second private network.