Patent ID: 8908603

Claim:
A method in a network in which a mobility management entity (MME) in a pool of MMEs is adapted for communicating with (i) at least one other MME in the pool of MMEs and (ii) a serving gateway (SGW), and is adapted for managing mobility of user entities (UEs) for establishing packet data communication between the SGW and UEs via at least a base station, the method comprising: establishing a UE context for a user entity (UE); appointing a back-up MME for holding a duplicate UE context of the user entity; informing the SGW of the back-up MME in which the duplicate context is held, or is to be held; and transmitting the duplicate UE context to the appointed back-up MME, wherein said appointing the back-up MME comprises using a predetermined function to select a MME as the back-up MME, wherein each MME in a subgroup of the MMEs in the pool uses said predetermined function to select a back-up MME such that any MME in the subgroup would appoint the same MME as a back-up MME for a given UE, the selected back-up MME being different than a registered MME for the given UE.