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NAS 5G

5G NAS - Registration Request

Starts a 5G registration or mobility update by sending UE identity and registration intent to the core.

UE -> AMF 3GPP TS 24.501
NGAP 5G

5G NGAP - Downlink NAS Transport

Downlink NAS Transport is the NGAP message the AMF uses to carry a downlink NAS message toward the UE through the NG-RAN over the N2 interface.

AMF -> NG-RAN 3GPP TS 38.413
RRC 5G

5G NR - RRC Setup

Downlink NR RRC message sent by the gNB to establish SRB1 and move the UE into the connected RRC procedure.

gNB -> UE 3GPP TS 38.331
NGAP 5G

5G NGAP - Uplink NAS Transport

Uplink NAS Transport is the NGAP message the NG-RAN uses to carry a subsequent uplink NAS message from the UE toward the AMF over the N2 interface after the initial access is already established.

NG-RAN -> AMF 3GPP TS 38.413
NGAP 5G

5G NR - Initial UE Message

NGAP initiating message used by the NG-RAN to transfer the UE's first uplink NAS message to the AMF.

NG-RAN -> AMF 3GPP TS 38.413
NGAP 5G

5G NGAP - Initial Context Setup Request

Initial Context Setup Request is the NGAP message the AMF sends to NG-RAN to establish UE context, security, and initial PDU session resources after successful NAS entry and core-side authentication steps.

AMF -> NG-RAN 3GPP TS 38.413
NAS LTE

LTE Attach Request

Attach Request is the EPS NAS message the UE uses to start the LTE attach procedure and ask the network to create EPS mobility-management context.

UE -> MME 3GPP TS 24.301
NGAP 5G

5G NGAP - NAS Non Delivery Indication

NAS Non Delivery Indication is the NGAP message the NG-RAN sends to the AMF when a downlink NAS message cannot be delivered to the UE.

NG-RAN -> AMF 3GPP TS 38.413
LTE RRC LTE

LTE RRC Connection Setup

Downlink LTE RRC message sent by the eNodeB to establish SRB1 and move the UE into connected-mode signaling.

eNodeB -> UE 3GPP TS 36.331
LTE RRC LTE

LTE RRC SIB1 - System Information Block Type 1

Broadcast LTE RRC message on BCCH and DL-SCH that gives the UE the essential access identity, cell selection, scheduling, and change-detection context needed before it can use the wider SIB set.

eNodeB -> UE 3GPP TS 36.331
NGAP 5G

5G NGAP - Paging

Paging is the NGAP message the AMF sends to NG-RAN to trigger UE reachability attempts in one or more tracking areas when the UE is not currently on an active UE-associated N2 signaling connection.

AMF -> NG-RAN 3GPP TS 38.413
NGAP 5G

5G NGAP - Initial Context Setup Response

Initial Context Setup Response is the NGAP message the NG-RAN sends to AMF to report successful or partial completion of the Initial Context Setup Request, including per-session setup outcomes.

NG-RAN -> AMF 3GPP TS 38.413
NGAP 5G

5G NGAP - PDU Session Resource Setup Request

PDU Session Resource Setup Request is the NGAP message the AMF sends to NG-RAN to request Uu and NG-U resources, DRBs, and QoS flow handling for one or more PDU sessions of an already identified UE.

AMF -> NG-RAN 3GPP TS 38.413
NGAP 5G

5G NGAP - Reroute NAS Request

Reroute NAS Request is the NGAP message the AMF sends to NG-RAN when the UE's NAS signaling should be rerouted toward a different AMF selection path.

AMF -> NG-RAN 3GPP TS 38.413
NGAP 5G

5G NGAP - UE Context Release Command

UE Context Release Command is the NGAP message the AMF sends to NG-RAN to order release of the UE-associated logical NG connection and associated access-side context.

AMF -> NG-RAN 3GPP TS 38.413
XnAP 5G

5G XnAP - Handover Request

Handover Request is the XnAP message the source NG-RAN node sends to the target NG-RAN node to request preparation of resources for an incoming handover on the Xn interface.

Source NG-RAN node -> Target NG-RAN node 3GPP TS 38.423
NGAP 5G

5G NGAP - Handover Required

Handover Required is the NGAP message the source NG-RAN sends to the AMF to request preparation of resources at the target during AMF-mediated mobility procedures.

Source NG-RAN -> AMF 3GPP TS 38.413
NGAP 5G

5G NGAP - Initial Context Setup Failure

Initial Context Setup Failure is the NGAP message the NG-RAN sends to AMF when the Initial Context Setup Request cannot be completed for the UE context or its requested setup state.

NG-RAN -> AMF 3GPP TS 38.413
NGAP 5G

5G NGAP - PDU Session Resource Setup Response

PDU Session Resource Setup Response is the NGAP message the NG-RAN sends to AMF to report which requested PDU session resources were successfully established and which failed.

NG-RAN -> AMF 3GPP TS 38.413
NGAP 5G

5G NGAP - UE Context Release Complete

UE Context Release Complete is the NGAP message the NG-RAN sends to AMF to confirm that the targeted UE-associated logical NG connection has been released.

NG-RAN -> AMF 3GPP TS 38.413
NGAP 5G

5G NGAP - Handover Request

Handover Request is the NGAP message the AMF sends to the target NG-RAN to request preparation of resources for an incoming UE during handover preparation.

AMF -> Target NG-RAN 3GPP TS 38.413
NGAP 5G

5G NGAP - PDU Session Resource Release Command

PDU Session Resource Release Command is the NGAP message the AMF sends to the NG-RAN to request release of already established PDU session resources for a given UE.

AMF -> NG-RAN 3GPP TS 38.413
NGAP 5G

5G NGAP - UE Context Modification Request

UE Context Modification Request is the NGAP message the AMF sends to NG-RAN to partly modify an already established UE context without rebuilding it from scratch.

AMF -> NG-RAN 3GPP TS 38.413
XnAP 5G

5G XnAP - Handover Request Acknowledge

Handover Request Acknowledge is the XnAP message the target NG-RAN node sends to the source NG-RAN node to report the prepared resources at the target and confirm that the handover branch is ready to continue.

Target NG-RAN node -> Source NG-RAN node successfulOutcome 3GPP TS 38.423