3GPP Message Database

Browse structured telecom message references for NR RRC, NAS, NGAP, LTE RRC, and S1AP. This database is built for scalable static publishing, so adding 100 or 500 more message pages stays maintainable.

Browse by Protocol

NR RRC Messages NR RRC messages manage radio control between the UE and gNB in 5G access. 5G NAS Messages NAS messages connect the UE to the 5G core for mobility, authentication, and session handling. NGAP Messages NGAP carries N2 signaling between the gNB and AMF in 5G core deployments. F1AP Messages F1AP carries signaling between the gNB-CU and gNB-DU in split gNB deployments. E1AP Messages E1AP carries signaling between the CU-CP and CU-UP in split user plane architectures. XnAP Messages XnAP carries signaling between gNB nodes over Xn for mobility and coordination. IMS / SIP Messages This category is reserved for SIP and IMS signaling used by VoNR procedures under the 5G architecture. LTE RRC Messages LTE RRC messages manage radio configuration and mobility between the UE and eNB. S1AP Messages S1AP handles control signaling between LTE eNBs and the MME over the S1-MME interface.

Popular Messages

RRC 5G

5G NR - RRCSetupComplete

Uplink NR RRC message sent by the UE on SRB1 and DCCH to confirm successful RRC connection establishment and transfer the initial NAS message.

UE -> gNB 3GPP TS 38.331

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

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

RRC 5G

5G NR - RRCSetupRequest

Uplink NR RRC message sent by the UE on SRB0 and CCCH to request establishment of an RRC connection.

UE -> gNB 3GPP TS 38.331

RRC 5G

5G NR - RRC Reconfiguration

Reconfigures the UE radio connection after setup, including bearers, measurements, and mobility.

gNB to UE 3GPP TS 38.331

RRC 5G

5G NR - SecurityModeCommand

Downlink NR RRC message used by the gNB to activate AS security for the UE in RRC_CONNECTED.

gNB -> UE 3GPP TS 38.331

Recently Added Messages

RRC 5G

5G NR - UECapabilityInformation

Uplink NR RRC message used by the UE to report its supported radio capability containers to the gNB.

UE -> gNB 3GPP TS 38.331

RRC 5G

5G NR - UECapabilityEnquiry

Downlink NR RRC message used by the gNB to request UE capability information needed for feature, bearer, mobility, and radio configuration decisions.

gNB -> UE 3GPP TS 38.331

RRC 5G

5G NR - SecurityModeFailure

Uplink NR RRC message used by the UE to indicate that the commanded AS security activation could not be completed successfully.

UE -> gNB 3GPP TS 38.331

RRC 5G

5G NR - SecurityModeComplete

Uplink NR RRC message used by the UE to confirm successful activation of the selected AS security configuration.

UE -> gNB 3GPP TS 38.331

RRC 5G

5G NR - SecurityModeCommand

Downlink NR RRC message used by the gNB to activate AS security for the UE in RRC_CONNECTED.

gNB -> UE 3GPP TS 38.331

RRC 5G

5G NR - RRCSetupRequest

Uplink NR RRC message sent by the UE on SRB0 and CCCH to request establishment of an RRC connection.

UE -> gNB 3GPP TS 38.331

Browse by Procedure

RRC Connection Establishment 4 related messages

Initial AS Security Activation 3 related messages

Initial Registration 3 related messages 5G Initial Registration 2 related messages

Capability-Aware RRC Reconfiguration 2 related messages

Connected-Mode Capability Discovery 2 related messages

Connected-Mode Security Setup 2 related messages

Initial Access 2 related messages

Database Snapshot

The current starter dataset includes 13 seeded messages and is wired for future markdown-driven expansion without changing the routing system.

Browse by spec or view popular messages.