Mobility Management Entity

The Mobility Management Entity (MME) is the key control-plane node for the LTE access network. It is responsible for idle mode UE tracking, paging, bearer activation/deactivation, and selecting the S-GW and P-GW for a UE.

The MME handles all the signaling between the UE and the core network for mobility, security, and session management. It authenticates users via interaction with the HSS and manages the security context.

The MME was introduced to replace the control-plane functions of the SGSN from 3G networks. In LTE's flat architecture, the MME provides centralized control while data flows directly through the gateways, reducing latency and improving efficiency.

Key motivations: - Separation of control and user plane for better scalability - Simplified handover procedures - Support for all-IP network architecture