5G NR - RRC Setup Complete

Message Fact Sheet

Protocol	rrc	Network	5g
Spec	3GPP TS 38.331	Spec Section	5.3.3.1, 5.3.3.3, 6.2.2
Direction	UE -> gNB	Message Type	Connection Control

Full message name	5G NR - RRC Setup Complete
Protocol	RRC
Technology	5G
Direction	UE -> gNB
Interface	Uu
Signaling bearer / channel	SRB1 / UL-DCCH
Typical trigger	The UE has successfully applied RRCSetup and is ready to confirm the setup while forwarding the first dedicated NAS message.
Main purpose	Confirms successful completion of RRC connection establishment, moves the procedure into core-facing signaling, and carries the dedicated NAS message toward the network.
Main specification	3GPP TS 38.331, 5.3.3.1, 5.3.3.3, 6.2.2
Release added	Release 15
Procedures where used	RRC Connection Establishment, Initial Registration, Mobility Registration Update, Periodic Registration Update, Service Request from Idle
Related timers	T300

What is RRC Setup Complete in simple terms?

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

Confirms successful completion of RRC connection establishment, moves the procedure into core-facing signaling, and carries the dedicated NAS message toward the network.

Why this message matters

RRCSetupComplete tells the gNB that the UE finished the initial radio setup and is now sending the first real NAS message, such as Registration Request.

Where this message appears in the call flow

5G RRC Connection Setup

Call flow position: UE response after applying the RRC Setup configuration.

Typical state: UE has entered connected-mode handling and can now use SRB1.

Preconditions:

RRCSetup has been received and successfully applied.
SRB1 is available.
The dedicated NAS payload is ready for transfer.

Next likely message: Initial UE Message on N2 and then AMF-driven response signaling

5G Initial Registration

Call flow position: Bridge message between radio setup and core registration signaling.

Typical state: UE is ready to deliver Registration Request into the network.

Preconditions:

Initial access and RRC setup completed successfully.

Next likely message: Initial UE Message

Call flow position

Previous message(s): RRCSetup

Next message(s): Initial UE Message, Security Mode Command, Downlink NAS Transport

Message direction and transport

Sender and receiver: UE -> gNB

Interface: Uu

Domain: Access-side radio control carrying core-bound NAS payload

Signaling bearer: SRB1

Logical channel: UL-DCCH

Transport / encapsulation: RRC over DCCH on SRB1 after the initial setup has been applied

Security context: Sent after SRB1 is established. Depending on the exact stage, the message is still before later AS security activation but already uses the dedicated control bearer rather than SRB0.

Message Structure Overview

RRCSetupComplete still uses the RRC transaction wrapper, but the operationally important payload is the dedicated NAS message plus selected PLMN and optional AMF or slice context.
Unlike RRCSetupRequest, this message is sent on SRB1 and therefore marks the move to the dedicated connected-mode control bearer.
Engineers should inspect the dedicatedNAS-Message first, then selectedPLMN-Identity and any AMF / S-NSSAI context.

ASN.1 for 5G NR - RRC Setup Complete

RRCSetupComplete ::= SEQUENCE {
  rrc-TransactionIdentifier RRC-TransactionIdentifier,
  criticalExtensions CHOICE {
    rrcSetupComplete RRCSetupComplete-IEs,
    criticalExtensionsFuture SEQUENCE {}
  }
}

RRCSetupComplete-IEs ::= SEQUENCE {
  selectedPLMN-Identity    INTEGER,
  registeredAMF            RegisteredAMF OPTIONAL,
  guami-Type               GUAMI-Type OPTIONAL,
  s-NSSAI-List             S-NSSAI-List OPTIONAL,
  dedicatedNAS-Message     DedicatedNAS-Message,
  ng-5G-S-TMSI-Value       NG-5G-S-TMSI-Value OPTIONAL,
  lateNonCriticalExtension OCTET STRING OPTIONAL,
  nonCriticalExtension     SEQUENCE {} OPTIONAL
}

How to read this ASN.1

In practice, read this message as the UE confirming setup and handing the first real NAS payload into the radio-to-core pipeline. The dedicatedNAS-Message is usually the most important field.

5G NR - RRC Setup Complete - Example Dump

UL-DCCH-Message
  message: rrcSetupComplete
    rrc-TransactionIdentifier: 1
    criticalExtensions:
      rrcSetupComplete:
        selectedPLMN-Identity: 1
        registeredAMF:
          plmn-Identity: 001-01
          amf-Identifier:
            regionID: 02
            setID: 341
            pointer: 1
        guami-Type: native
        s-NSSAI-List:
          - sst: 1
        dedicatedNAS-Message:
          Registration Request
            Extended Protocol Discriminator: 5GMM
            Security Header Type: Plain NAS
            Message Type: Registration Request
            5GS Registration Type: Initial Registration
            UE Identity: SUCI
        ng-5G-S-TMSI-Value:
          ng-5G-S-TMSI-Part2: 0x101

How to read this dump

selectedPLMN-Identity should match the PLMN selection broadcast and chosen by the UE.
The key payload is dedicatedNAS-Message because it tells the network what core procedure starts next.
If present, registeredAMF and slice information can influence how the later core handling proceeds.

Important Information Elements

IE	Required	Description
`rrc-TransactionIdentifier`	Yes	Transaction identifier matching the RRC setup transaction being completed.
`selectedPLMN-Identity`	Yes	Index of the PLMN or SNPN selected by the UE from the plmn-IdentityInfoList or npn-IdentityInfoList broadcast in SIB1.
`registeredAMF`	Optional	Transfers the GUAMI of the AMF where the UE is registered, as provided by upper layers.
`guami-Type`	Optional	Indicates whether the GUAMI is native or mapped.
`s-NSSAI-List`	Optional	Carries one or more S-NSSAI values provided by upper layers for slice-related access handling.
`dedicatedNAS-Message`	Yes	Mandatory NAS message container used to transfer the initial UE-specific NAS message transparently through RRC.
`ng-5G-S-TMSI-Value`	Optional	Optional NG-5G-S-TMSI value. In the normal RRCSetupRequest -> RRCSetup -> RRCSetupComplete path, the UE sets the Part2 form when upper layers provide a 5G-S-TMSI.
`lateNonCriticalExtension`	Optional	Late non-critical extension container used for release evolution and backward compatibility.
`nonCriticalExtension`	Optional	Regular extension branch used for later release additions such as idle measurement availability, mobility history, UL RRC segmentation, onboarding request, NCR indication, and mobile IAB indication.

Detailed field explanation

`rrc-TransactionIdentifier`

Transaction identifier matching the RRC setup transaction being completed.

Presence: Required

In practice: In practice, compare this field with the original request and with any later release-dependent optional fields so you can see whether the network accepted the same service model the UE asked for.

`selectedPLMN-Identity`

Index of the PLMN or SNPN selected by the UE from the plmn-IdentityInfoList or npn-IdentityInfoList broadcast in SIB1.

Presence: Required

In practice: In practice, compare this field with the original request and with any later release-dependent optional fields so you can see whether the network accepted the same service model the UE asked for.

`registeredAMF`

Transfers the GUAMI of the AMF where the UE is registered, as provided by upper layers.

Presence: Optional

In practice: In practice, compare this field with the original request and with any later release-dependent optional fields so you can see whether the network accepted the same service model the UE asked for.

`guami-Type`

Indicates whether the GUAMI is native or mapped.

Presence: Optional

In practice: In practice, compare this field with the original request and with any later release-dependent optional fields so you can see whether the network accepted the same service model the UE asked for.

`s-NSSAI-List`

Carries one or more S-NSSAI values provided by upper layers for slice-related access handling.

Presence: Optional

In practice: This is the slice context that ties the session to the network selection outcome. In roaming or slice-specific cases, it is one of the strongest indicators of whether the session landed on the expected slice.

`dedicatedNAS-Message`

Mandatory NAS message container used to transfer the initial UE-specific NAS message transparently through RRC.

Presence: Required

In practice: In practice, compare this field with the original request and with any later release-dependent optional fields so you can see whether the network accepted the same service model the UE asked for.

`ng-5G-S-TMSI-Value`

Optional NG-5G-S-TMSI value. In the normal RRCSetupRequest -> RRCSetup -> RRCSetupComplete path, the UE sets the Part2 form when upper layers provide a 5G-S-TMSI.

Presence: Optional

In practice: In practice, compare this field with the original request and with any later release-dependent optional fields so you can see whether the network accepted the same service model the UE asked for.

`lateNonCriticalExtension`

Late non-critical extension container used for release evolution and backward compatibility.

Presence: Optional

In practice: In practice, compare this field with the original request and with any later release-dependent optional fields so you can see whether the network accepted the same service model the UE asked for.

`nonCriticalExtension`

Regular extension branch used for later release additions such as idle measurement availability, mobility history, UL RRC segmentation, onboarding request, NCR indication, and mobile IAB indication.

Presence: Optional

In practice: In practice, compare this field with the original request and with any later release-dependent optional fields so you can see whether the network accepted the same service model the UE asked for.

What to check in logs and traces

Confirm the message follows a valid RRCSetup and uses SRB1 / UL-DCCH.
Decode the embedded dedicatedNAS-Message fully and correlate it with the expected procedure.
Check selectedPLMN-Identity against SIB1 broadcast information and UE selection.
Inspect any registeredAMF or NG-5G-S-TMSI-related context for consistency with prior UE state.
Correlate the message with the subsequent Initial UE Message on N2.

Common Issues and Troubleshooting

RRCSetupComplete is missing after RRCSetup.

Likely cause: The UE may have failed while applying RRC Setup or failed before assembling the dedicated NAS payload.

What to inspect: Check RRCSetup content, SRB1 bring-up, and whether the UE can build the NAS message.

Next step: Troubleshoot the transition from RRCSetup to SRB1-based uplink signaling.

RRCSetupComplete is present but the core procedure fails immediately.

Likely cause: The embedded NAS message or identity context may be wrong even though the radio procedure succeeded.

What to inspect: Decode dedicatedNAS-Message, selected PLMN, and AMF-related fields, then compare with Initial UE Message.

Next step: Shift troubleshooting from pure RRC to the NAS / NGAP handoff path.

Unexpected PLMN or AMF context is used.

Likely cause: selectedPLMN-Identity or registeredAMF-related fields may not match the scenario.

What to inspect: Check SIB1 selection context, GUAMI usage, and any temporary identity values.

Next step: Validate PLMN selection and UE context assumptions.

LTE / 5G / Variant Comparison

Compared with RRCSetupRequest

RRCSetupRequest asks for access on SRB0 and contains no NAS payload. RRCSetupComplete confirms setup on SRB1 and carries the dedicated NAS message that launches the core procedure.

FAQ

What is RRCSetupComplete in 5G NR?

It is the uplink RRC message that confirms successful RRC connection establishment and carries the UE's initial NAS message toward the network.

What NAS message is usually inside RRCSetupComplete?

Common examples are Registration Request and Service Request, depending on why the UE initiated the connection.

Does RRCSetupComplete use SRB0 or SRB1?

RRCSetupComplete is sent on SRB1 using DCCH and RLC AM, unlike RRCSetupRequest which is sent on SRB0 and CCCH.

What comes after RRCSetupComplete?

The network typically forwards the NAS message toward the AMF and continues with procedures such as Initial UE Message, Downlink NAS Transport, and Security Mode Command.

Related message pages

Related Procedures

Related Tools

Use This Reference in Practice

Decode this message with the 3GPP Decoder, inspect the related message database, or open the matching call flow to see where this signaling step fits in the full procedure.