Patent ID: 8060622

Claim:
A method for session re-establishment in a server for providing a messenger service between the server and client terminal, comprising the steps of: receiving a request for session re-establishment for a session from the client terminal after an access of the client terminal to the session is terminated; detecting a synckey, including a session ID of the session between the client terminal and the server, a client ID of the client terminal and a transaction ID of the communication between the client terminal and the server, from the received request for session re-establishment; confirming session information on the session stored in the client terminal based on the detected synckey and comparing the confirmed session information to updated session information on the session stored in a database of the server; detecting updated data, which represents a difference in data between the session information stored in the client terminal and the updated session information, according to a result of the comparison; and sending a reply for requesting session re-establishment including the updated data to the client terminal.