Mobility Management Entity (MME)

Description: The MME is the central nervous system of the LTE control plane. Its responsibilities are extensive:

• NAS Signaling: Handles all Non-Access Stratum signaling with the UE, including authentication and security key management.
• Mobility Management: Tracks UE location and manages tracking area lists.
• Session Management: Initiates the establishment and teardown of data bearers.
• Gateway Selection: Chooses the optimal Serving GW (SGW) and PDN GW (PGW) for the UE’s session.
• Context & Deployment: The MME connects to eNodeBs via the S1-MME interface (SCTP protocol) and to the HSS using the Diameter-based S6a interface. Its logs are detailed, making it excellent for debugging attachment procedures, handovers, and bearer activation.
• Interfaces: S1-AP, S6a, S11, S10, SGsAP, and S3