The Mobility Management Entity (MME) is a nodal element within the LTE EPC.
It performs the signaling and control functions to manage the User Equipment (UE) access to network connections,
the assignment of network resources, and the management of the mobility states to support tracking,paging, roaming and handovers. MME controls all control plane functions related to subscriber and session management.
MME manages thousands of eNodeB elements, which is one of the key differences from requirements previously seen in 2G/3G (on RNC/SGSN platforms). The MME is the key element for gateway selection within the EPC (Serving and PDN). It also performs signaling and selection of legacy gateways for handovers for other 2G/3G networks. The MME also performs the bearer management control functions to establish the bearer paths that the UEs use.
The MME supports the following functions:
• Security procedures: End-user authentication as well as initiation and negotiation of ciphering and integrity protection algorithms.
• Terminal-to-network session handling: All the signaling procedures used to set up packet data context and negotiate associated parameters like QoS.
• Idle terminal location management: The tracking area update process used to enable the network to join terminals for incoming sessions.