Method for determining whether to offload traffic to WLAN

A method for supporting network based Internet Protocol (IP) flow mobility (NBIFOM) in a mobile communication network, the method performed by a gateway and comprising:

• receiving NBIFOM function information of a user equipment (UE) and network nodes and a wireless local area network (WLAN) offloadability information for a packet data network (PDN);
• determining whether to perform NBIFOM for allowing the PDN to be offloaded to the WLAN by performing the NBIFOM based on the function of the NBIFOM of the gateway, the received NBIFOM function information of the network nodes and the UE, and the received WLAN offloadability information;
• and
• transmitting a result that the NBIFOM is disabled to the UE and the network nodes when it is determined that the PDN is disabled to be offloaded to the WLAN based on the received WLAN offloadability information even though the NBIFOM is enabled to be performed based on the received NBIFOM function information of the network nodes and the UE.

A network entity for determining whether to offload traffic of a user equipment (UE) to a wireless local area network (WLAN), the network entity comprising:

• a transceiver;
• and
• a processor operatively connected to the transceiver,
• wherein the processor is configured to:
• control the transceiver to receive subscriber information on the UE from a subscriber information server, wherein the subscriber information includes a first WLAN offloadability information for a packet data network (PDN) connection,
• determine WLAN offloadability for the PDN based on the first WLAN offloadability indication and configuration information,
• control the transceiver to transmit network based Internet Protocol (IP) flow mobility (NBIFOM) function information of the network entity and a second WLAN offloadability information for the PDN connection which includes the determined WLAN offloadability to network nodes, which include a serving gateway (S-GW) and a PDN gateway (P-GW), and
• control the transceiver to transmit the second WLAN offloadability information to the UE,
• wherein when the determined WLAN offloadability is that the PDN is disabled to be offloaded to the WLAN, the second WLAN offloadability information is used as a highest priority condition among a plurality of conditions which are used by the P-GW for determining whether to perform the NBIFOM for allowing the PDN to be offloaded to the WLAN.