5G NAS Messages – Complete 5GMM and 5GSM Message List
5G NAS, or Non-Access Stratum signalling, is the control-plane signalling between the UE and the 5G Core. Defined mainly in 3GPP TS 24.501, NAS includes 5GMM mobility-management messages and 5GSM session-management messages used for registration, authentication, security, service request, deregistration, PDU session establishment, modification, release, and transport of NAS payloads.
Use this page to search or browse 5G NAS messages by procedure category. Each message page explains the message direction, trigger, call-flow role, key fields, and practical troubleshooting notes.
Based on 3GPP TS 24.501
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Registration Messages
5GMM messages used when the UE registers, updates registration, or receives registration acceptance/rejection.
Registration Request
Starts registration, periodic update, or mobility registration update.
Registration Accept
Accepts registration and returns 5GMM registration context.
Registration Complete
Confirms completion of registration acceptance handling.
Registration Reject
Rejects registration with a 5GMM cause and retry context.
Authentication Messages
5GMM messages used for primary authentication and authentication result handling.
Authentication Request
Starts primary authentication challenge handling.
Authentication Response
Returns the UE authentication response to the network.
Authentication Reject
Rejects authentication and stops the authentication attempt.
Authentication Failure
Reports that the UE could not complete authentication.
Authentication Result
Returns EAP or authentication result information where applicable.
Security Messages
NAS security mode control messages used to activate or reject selected NAS security algorithms.
Service Request Messages
Messages used when a registered UE requests service or signalling connection handling.
Service Request
Requests service or signalling connection handling from a registered UE.
Service Accept
Accepts the service request and resumes requested service handling.
Service Reject
Rejects service request with a 5GMM cause.
Control Plane Service Request
Requests control-plane service for signalling or data transfer.
Deregistration Messages
Messages used for UE-originated and network-initiated deregistration.
Deregistration Request (UE Originating)
Starts UE-originated deregistration from 5GS.
Deregistration Accept (UE Originating)
Confirms UE-originated deregistration handling.
Deregistration Request (UE Terminated)
Starts network-initiated deregistration toward the UE.
Deregistration Accept (UE Terminated)
Confirms network-initiated deregistration handling.
Configuration Update Messages
Network-initiated 5GMM configuration update messages after registration.
NAS Transport Messages
NAS wrapper messages used to carry additional NAS payloads between UE and network.
UL NAS Transport
Carries uplink NAS payloads from UE to AMF.
DL NAS Transport
Carries downlink NAS payloads from AMF to UE.
NAS Non Delivery Indication
Indicates NAS payload delivery failure where supported.
Coming soonIdentity and Notification Messages
Messages used for UE identity retrieval and NAS notification handling.
PDU Session Establishment Messages
5GSM messages used to create a new PDU session.
PDU Session Modification Messages
5GSM messages used to modify an active PDU session.
PDU Session Modification Request
Requests modification of an active PDU session.
PDU Session Modification Command
Commands UE-side PDU session modification.
PDU Session Modification Complete
Confirms completion of commanded PDU session modification.
PDU Session Modification Command Reject
Rejects a network-commanded PDU session modification.
PDU Session Modification Reject
Rejects UE-requested PDU session modification.
PDU Session Release Messages
5GSM messages used to release an active PDU session.
5GSM Status & Error Handling Messages
Session-management status and error reporting messages.
Slice / Service Authentication Messages
Messages used for network slice-specific authentication and service-level authentication/authorization.
Network Slice-Specific Authentication Command
Starts network slice-specific authentication.
Network Slice-Specific Authentication Complete
Confirms completion of slice-specific authentication.
Network Slice-Specific Authentication Result
Returns the result of network slice-specific authentication.
Service-level Authentication Command
Starts service-level authentication or authorization.
Service-level Authentication Complete
Confirms service-level authentication or authorization completion.
PDU Session Authentication Command
Starts PDU session authentication or authorization.
PDU Session Authentication Complete
Confirms PDU session authentication completion.
PDU Session Authentication Result
Returns PDU session authentication result information.
Relay / ProSe Messages
NAS messages used for relay authentication, relay key handling, and ProSe support.
Relay Authentication Request
Requests relay authentication for ProSe or relay operation.
Relay Authentication Response
Returns relay authentication response information.
Relay Key Request
Requests relay key handling for ProSe relay operation.
Relay Key Accept
Accepts relay key handling and returns key-related context.
Relay Key Reject
Rejects relay key handling with cause context.
Remote UE Reporting Messages
NAS messages used to report remote UE information and relay-related reporting results.
Most Used NAS Messages
Common NAS Procedure Flows
Registration
Registration Request -> Authentication -> Security Mode -> Registration Accept -> Registration Complete
Authentication
Authentication Request -> Authentication Response -> Authentication Result / Authentication Reject
Security
Security Mode Command -> Security Mode Complete / Security Mode Reject
Service Request
Service Request -> Service Accept / Service Reject
PDU Session Establishment
PDU Session Establishment Request -> PDU Session Establishment Accept / Reject
PDU Session Modification
PDU Session Modification Request -> PDU Session Modification Command -> Complete / Command Reject
PDU Session Release
PDU Session Release Request -> PDU Session Release Command -> Release Complete
FAQ
What are 5G NAS messages?
5G NAS messages are Non-Access Stratum control-plane messages exchanged between the UE and the 5G Core for mobility management, security, service request, deregistration, and session management.
What is the difference between 5GMM and 5GSM?
5GMM handles mobility-management procedures such as registration, authentication, security, service request, and deregistration. 5GSM handles session-management procedures such as PDU session establishment, modification, release, and status reporting.
Which specification defines 5G NAS?
5G NAS is defined mainly in 3GPP TS 24.501.
What are the most important 5G NAS messages?
Commonly analyzed 5G NAS messages include Registration Request, Registration Accept, Authentication Request, Authentication Response, Security Mode Command, Security Mode Complete, Service Request, PDU Session Establishment Request, UL NAS Transport, and DL NAS Transport.
What is the difference between NAS and NGAP?
NAS is UE-to-core signalling between the UE and AMF or SMF. NGAP is N2 signalling between NG-RAN and AMF and often transports NAS payloads across the access network.
What is the role of NAS in registration?
NAS carries the registration request, authentication, security activation, registration acceptance or rejection, and registration completion messages used to create 5G mobility context.
What is the role of NAS in PDU session establishment?
NAS 5GSM messages request, accept, or reject PDU session establishment and carry session parameters such as DNN, S-NSSAI, SSC mode, QoS, and session-related causes.
References
- 3GPP TS 24.501 – Non-Access-Stratum protocol for 5GS
- 3GPP TS 23.501 – 5G System architecture
- 3GPP TS 23.502 – 5G System procedures