MME is Mobility Management Entity, control node of SAE/EPC architecture. It works simultaneously with access network and core network with different interfaces. Access Network is network which is facing towards eNodeB and core network is that network which is facing towards S-Gateway/P-Gateway.

Interfaces of MME
· S1-MME:- This interfaces is facing towards enodeB. A very crucial interface which is responsible for UE management with various different type of control messages.
· S11:- This interface is facing towards S-Gateway
· S6a:- This interface is facing towards HSS

Functions of MME
Below is the list of functions performed by S1-MME interfaces:-
· Network Access Control
· Radio Resource Management
· Mobility Management(Handover Management)
· Roaming management
· UE Reach ability
· Tracking Area Management
· Load balancing Between different S gateway
· Paging
· Session Management
· Location Aware Applications

Below is the list of functions performed by S11 interfaces
· PDN Gateway and Serving Gateway selection on the basics of DNS
· Bearer Activation and Deactivation Responsible for handovers from LTE to 3G circuit switched domain in case of voice calls.
Lawful Intercept