Patent ID: 8908528

Claim:
A method for managing a backup service gateway (SGW) associated with a primary SGW, the method comprising: in a slave mode of operation, the backup SGW periodically receiving from the primary SGW at least a portion of corresponding UE session state information stored at the primary SGW; and in response to a failure of the primary SGW, the backup SGW entering a master mode of operation, said master mode of operation comprising: assuming management of IP addresses and paths associated with said primary SGW; and waiting until control plane or data plane traffic associated with a UE is received before generating a Downlink Data Notification (DDN) message and transmitting said DDN message to inform a Mobility Management Entity (MME) indicating that the UE is in a live state and cause said MME to provide to said backup SGW attachment information associated with said UE, so that the MME will find or page the UE to enable the UE to properly respond to the control plane or the data plane traffic.