A method for mailbox migration includes creating a message ID map for the source and destination mailboxes, and storing the message ID map in a migration cache file that can also hold message ID persistence and message state indicator data. The matable end of the connector may be of a female or male type and may be of a post, tube, blade, pin, or other configuration. To control in-sequence delivery of the Internet Protocol packets for the given TCP connection, the radio link control entity inserts and uses port-specific sequence numbers in the RLC protocol data units which carry the Internet Protocol packets for the given TCP connection. When the result received is the option other than the driver setting option, display a setting value that corresponds to the option selected in the application-side setting process as the value for the item.