The MME Function

• NAS signalling;
• NAS signalling security;
• AS Security control;
• Inter CN node signalling for mobility between 3GPP access networks;
• Idle mode UE Reachability (including control and execution of paging retransmission);
• Tracking Area list management (for UE in idle and active mode);
• PDN GW and Serving GW selection;
• MME selection for handovers with MME change;
• SGSN selection for handovers to 2G or 3G 3GPP access networks;
• Roaming;
• Authentication;
• Bearer management functions including dedicated bearer establishment;
• Support for PWS (which includes ETWS and CMAS) message transmission.