Method, apparatus, and system for establishing connection

A terminal device for establishing a connection, comprising:

• a transmitter, configured to send connection resumption request information to a first radio access network (RAN) element, wherein the first RAN element is a RAN element corresponding to a cell on which the terminal device currently camps, the first RAN element is a RAN element indicated by configuration information of a master cell corresponding to the terminal device in a connected state, the terminal device is in an inactive state, the terminal device stores configuration information by using a storage unit, and the configuration information comprises information about a secondary cell corresponding to the terminal device in the connected state;
• a receiver, configured to receive acknowledgement information from the first RAN element, wherein the acknowledgement information is in response to the connection resumption request information;
• and
• a processor, configured to determine to resume a connection to a second RAN element based on the acknowledgement information comprising information for indicating to the terminal device to maintain configuration information of the secondary cell, wherein the second RAN element is indicated by the configuration information of the secondary cell, and configured to resume the connection to the second RAN element.

A first radio access network (RAN) element device for establishing a connection, comprising:

• a receiver, configured to receive connection resumption request information from a terminal device, wherein the connection resumption request information comprises an identifier of the terminal device;
• a processor, configured to obtain, based on the identifier of the terminal device in the connection resumption request information received by the receiver, configuration information of a secondary cell corresponding to the terminal device in a connected state;
• and
• a transmitter, configured to send acknowledgement information to the terminal device in response to the connection resumption request information and to indicate to the terminal device to resume a connection to a second RAN element according to the acknowledgement information, wherein the acknowledgement information comprises information for indicating to the terminal device to maintain configuration information of the secondary cell and the second RAN element is a RAN element indicated by the configuration information of the secondary cell.