Patent ID: 7830839

Claim:
A method of operation in a communication system to facilitate transmission of data messages to a mobile node when the mobile node is served in a network which is not its home network, the method including: within the mobile node: (a) when attached to a first service node identifying a second service node as a candidate service node to which the mobile node can become attached by an attachment handover procedure; (b) obtaining a new Care Of Address for use with attachment of the mobile node to the second service node; (c) notifying the second service node of its identity and of its new Care Of Address; (d) notifying a Home Agent for the mobile node of the identity of the second service node and/or of the new Care Of Address; wherein steps (b), (c) and (d) are carried out before any attachment handover to the second service node; and (e) in response to the notification in step (c) the second service node establishing a capability to route data messages addressed to the mobile node at the new Care Of Address; (f) the Home Agent in response to the notification in step (d) establishing a capability to send duplicate copies of data messages addressed to the mobile node at (i) a current Care Of Address associated with attachment of the mobile station to the first service node and at (ii) the new Care Of Address obtained in step (b); after (f) the Home Agent notifying the mobile node that the duplication of messages has been started; (g) following steps (e) and (f) the mobile node completing service attachment handover from the first service node to the second service node; (h) following completion of the handover, the mobile node notifying the Home Agent of completion of the handover; and (i) in response to (h), the Home Agent stopping the duplication of data messages, the data messages being forwarded only to the new Care Of Address after the stopping of duplication.