Patent ID: 8559299

Claim:
A method performed in a first packet data network gateway (PDN-GW) in a PDN-GW pool, the PDN-GW pool for providing data connectivity between user equipment (UE) devices and an external PDN through an access point name (APN), wherein the first PDN-GW is coupled to a second PDN-GW and the method is for providing UE session resilience by allowing the first PDN-GW to provide connectivity for a set of one or more UE sessions previously serviced by the second PDN-GW after the second PDN-GW becomes non-operational, the method comprising the steps of: recognizing that the second PDN-GW is entering a non-operational state; establishing a temporary data tunnel with the second PDN-GW to be used by the second PDN-GW to forward data traffic received for the set of UE sessions to the first PDN-GW to prevent service interruption to the set of UE sessions through a graceful switchover; receiving, over the temporary data tunnel from the second PDN-GW, the forwarded data traffic of the set of UE sessions; activating a set of one or more standby UE sessions, wherein the set of standby UE sessions are synchronized copies of the set of UE sessions for which the second PDN-GW was the active PDN-GW, each of the set of UE sessions being associated with a UE device and a network resource identifier (NRI) that identifies an APN slice which corresponds with a subset of internet protocol addresses in the external PDN; transmitting a message to a serving gateway (SGW), the SGW for providing data connectivity between one or more of the UE devices and the PDN-GW pool, wherein the message indicates that the first PDN-GW has activated the set of standby UE sessions associated with one or more UE devices serviced by the SGW to cause the SGW to direct traffic previously bound for the second PDN-GW to the first PDN-GW; and closing the temporary data tunnel after the SGW begins directing the traffic previously bound for the second PDN-GW to the first PDN-GW, whereby UE session resilience is achieved in a PDN-GW pool by allowing the first PDN-GW to activate the set of standby UE sessions without notifying each of the UE devices associated with the standby UE sessions on the first PDN-GW and without causing service interruption to the set of UE sessions.