Target cell access method and device

A system for communications between a terminal device and an access network device, comprising:

• a serving access network device and a target access network device;
• the serving access network device comprises:
• at least one processor;
• a non-transitory computer-readable storage medium coupled to the at least one processor and storing programming instructions for execution by the at least one processor, the programming instructions instruct the serving access network device to:
• send a node addition request message to the target access network device to request the target access network device to allocate a resource for multi-connection operation for a terminal device, wherein the node addition request message comprises identification information of a network slice that serves the terminal device, the identification information of the network slice comprises a network slice type, the node addition request message further comprises a security capability of the terminal device, a security key of the target access network device, an identifier of a session, and security information for the session, and wherein the security capability of the terminal device indicates a ciphering algorithm and an integrity protection algorithm supported by the terminal device, the security key of the target access network device is used by the target network device to perform data encryption for the terminal device, the security information for the session comprises a ciphering function enabling option indicating whether a ciphering function is enabled for the session and an integrity protection enabling option indicating whether integrity protection is enabled for the session;
• send a radio resource control (RRC) connection reconfiguration message to the terminal device, wherein the RRC connection reconfiguration message comprises information of a radio resource configuration;
• receive a RRC connection reconfiguration complete message from the terminal device;
• and
• send a message indicating that the terminal device has completed the radio resource configuration to the target access network device;
• and
• the target access network device comprises:
• at least one processor;
• a non-transitory computer-readable storage medium coupled to the at least one processor and storing programming instructions for execution by the at least one processor, the programming instructions instruct the serving access network device to:
• send an addition request acknowledgement message to the serving network device.