Patent ID: 8218490

Claim:
A method for roaming of a wireless mobile communication unit between Public Land Mobile Networks (PLMN) comprising: sending a context request from a second service support node in a second PLMN to a first service support node in a first PLMN; receiving a context response in the second service support node from the first service support node; sending a context acknowledgement from the second service support node to the first service support node; sending a relocate Packet Data Protocol (PDP) context request from the second service support node to a second proxy gateway support node in the second PLMN; sending an update PDP context request to a home gateway support node in a Home PLMN of the wireless mobile communication unit from the second proxy gateway support node; receiving in the second proxy gateway support node an update PDP context response; sending a relocate PDP context response to the second service support node from the second proxy gateway support node; sending an update location message from the second service support node to a home location register in the Home PLMN of the wireless mobile communication unit; and receiving an update location acknowledgement message in the second service support node from the home location register.