5G NAS Mobility Management - 5GMM

The major functionality of 5GMM

• Registration 
• De-registration 
• eCall inactivity procedure
• Connected mode procedure - network-initiated NAS transport, primary authentication, and key agreement procedure, security mode control, generic UE configuration update, identification and UE initiated NAS transport. 
• Connection management procedure - service request, paging, and notification. 

5G Mobility Management: 5GMM procedures are used to keep track of the whereabouts of the UE, to authenticate the UE, and to control integrity protection and ciphering. The 5G MM procedures also allow the network to assign new temporary identities to the UE (5G-GUTI) and also request identity information (SUCI and PEI) from the UE. 5G MM procedures provide the UE’s capability information to the network and the network may also inform the UE about information regarding specific services in the network. The 5G MM procedures provide the UE’s capability information to the network and the network may also inform the UE about information regarding specific services in the network. 

Basic MM procedures

• Registration 
• Deregistration 
• Authentication 
• Security mode control 
• Service request 
• Notification 
• Uplink NAS transport
• Downlink NAS transport
• UE configuration update
• UE identity request 

The 5G MM procedures can only be performed if a NAS signaling connection has been established between the UE and the AMF. If there is no active signaling connection, the 5G MM layer has to initiate the establishment of a NAS signaling connection.  

The NAS signaling connection is established by a Registration or a Service request procedure from the UE.  For Downlink NAS signaling, if there is no active signaling connection the AMF first initiates a paging procedure that triggers the UE to execute the Service Request procedure. 

5G MM Registration & De-Registration procedures

1. Registration request
2. Registration accept
3. Registration complete
4. Registration reject
5. De-registration request 
6. De-registration accept 

5G MM connection management procedures

1. Service request
2. Service reject
3. Service accept 
4. Paging 
5. Notification
6. Notification update 

5G MM common procedures

1. UE configuration update command
2. UE configuration update complete
3. Authentication request
4. Authentication response 
5. Authentication reject
6. Authentication failure
7. Authentication result 
8. Identity request
9. Identity response
10. Security mode command
11. Security mode complete 
12. Security mode reject
13. UL NAS transport
14. DL NAS transport