NAS i.e. Non-Access-Stratum is highest stratum of the control plane between UE and MME at the radio interface which is transparently passed by the access network. Main functions of the protocols that are part of the NAS are the support of mobility of the user equipment (UE) and the support of session management procedures to establish and maintain IP connectivity between the UE and a packet data network gateway (PDN GW).
NAS Protocol performs followings operations:
1. EPS bearer management;
2. Authentication;
3. ECM-IDLE mobility handling;
4. Paging origination in ECM-IDLE;
5. Security control.
Complete List of NAS messages (LTE and UMTS)
EPS session management message
Call Ctrl and Call Related SS message
Mobility Management message
EPS mobility management message
GPRS mobility management message
SMS message
GPRS Session Management message
Non call related SS message
Activate default EPS bearer context request
Activate default EPS bearer context accept
Activate default EPS bearer context reject
Activate dedicated EPS bearer context request
Activate dedicated EPS bearer context accept
Activate dedicated EPS bearer context reject
Modify EPS bearer context request
Modify EPS bearer context accept
Modify EPS bearer context reject
Deactivate EPS bearer context request
Deactivate EPS bearer context accept
PDN connectivity request
PDN connectivity reject
PDN disconnect request
PDN disconnect reject
Bearer resource allocation request
Bearer resource allocation reject
Bearer resource modification request
Bearer resource modification reject
ESM information request
ESM information response
Notification
ESM status
Alerting(Uplink)
Alerting(Downlink)
Call Proceeding
Progress
CC-Establishment
Setup(Uplink)
Setup(Downlink)
CC-Establishment Confirmed
Connect(Uplink)
Connect(Downlink)
Call Confirmed
Start CC
Recall
Emergency Setup
Connect Acknowledge
User Information
Modify Reject
Modify
Hold
Hold Acknowledge
Hold Reject
Retrieve
Retrieve Acknowledge
Retrieve Reject
Modify Complete
Disconnect(Uplink)
Disconnect(Downlink)
Release Complete(Uplink)
Release Complete(Downlink)
Release(Uplink)
Release(Downlink)
Stop DTMF
Stop DTMF Acknowledge
Status Enquiry
Start DTMF
Start DTMF Acknowledge
Start DTMF Reject
Congestion Control
Facility(Uplink)
Facility(Downlink)
Status
Notify
IMSI Detach Indication
Location Updating Accept
Location Updating Reject
Location Updating Request
Authentication Reject
Authentication Request
Authentication Response
Identity Request
Identity Response
TMSI Reallocation Command
TMSI Reallocation Complete
Authentication Failure
CM Service Accept
CM Service Reject
CM Service Abort
CM Service Request
CM Service Prompt
CM Reestablishment Request
Abort
MM Null
MM Status
MM Information
Attach request
Attach accept
Attach complete
Attach reject
Detach request (UE originated detach)
Detach request (UE terminated detach)
Detach accept
Tracking area update request
Tracking area update accept
Tracking area update complete
Tracking area update reject
Extended service request
Service reject
GUTI reallocation command
GUTI reallocation complete
Authentication request
Authentication response
Authentication reject
Identity request
Identity response
Authentication failure
Security mode command
Security mode complete
Security mode reject
EMM status
EMM information
Downlink NAS transport
Uplink NAS transport
CS Service notification
Downlink generic NAS transport
Uplink generic NAS transport
Service request
Attach Request
Attach Accept
Attach Complete
Attach Reject
Detach Request(Uplink)
Detach Request(Downlink)
Detach Accept(Uplink)
Detach Accept(Downlink)
Routing Area Update Request
Routing Area Update Accept
Routing Area Update Complete
Routing Area Update Reject
P-TMSI Reallocation Command
P-TMSI Reallocation Complete
Authentication and Ciphering Request
Authentication and Ciphering Response
Authentication and Ciphering Reject
Authentication and Ciphering Failure
GMM Identity Request
Identity Response
GMM Status
GMM Information
Service Request
Service Accept
Service Reject
CP-DATA
CP-ACK
CP-ERROR
Activate PDP Context Request
Activate PDP Context Accept
Activate PDP Context Reject
Request PDP Context Activation
Request PDP Context Activation Reject
Deactivate PDP Context Request
Deactivate PDP Context Accept
Modify PDP Context Request(Downlink)
Modify PDP Context Accept(Uplink)
Modify PDP Context Request(Uplink)
Modify PDP Context Accept(Downlink)
Modify PDP Context Reject
Activate Secondary PDP Context Request
Activate Secondary PDP Context Accept
Activate Secondary PDP Context Reject
SM Status
Activate MBMS Context Request
Activate MBMS Context Accept
Activate MBMS Context Reject
Request MBMS Context Activation
Request MBMS Context Activation Reject
Request Secondary PDP Context Activation
Request Secondary PDP Context Activation Reject
Notification
Release Complete
Facility Message
Register(Uplink)
Register(Downlink)
