RRC 5G UE -> gNB 3GPP TS 38.331

5G NR - RRC Resume Request1

RRC Resume Request1 is an alternate NR RRC resume request message variant used in the resume procedure.

Message Fact Sheet

Protocol	rrc	Network	5g
Spec	3GPP TS 38.331	Spec Section	5.3.13, 6.2.2
Direction	UE -> gNB	Message Type	Connection Resume

Full message name	5G NR - RRC Resume Request1
Protocol	RRC
Technology	5G
Direction	UE -> gNB
Interface	Uu
Signaling bearer / channel	SRB0 / UL-CCCH
Typical trigger	Used when the UE follows the RRCResumeRequest1 variant defined for the resume path.
Main purpose	Provides the UE with an alternate resume-request encoding path defined by the specification.
Main specification	3GPP TS 38.331, 5.3.13, 6.2.2
Release added	Release 15
Procedures where used	RRC Resume, Inactive-to-Connected Transition
Related timers	T380
Related cause values	None highlighted

What is RRC Resume Request1 in simple terms?

RRC Resume Request1 is an alternate NR RRC resume request message variant used in the resume procedure.

Provides the UE with an alternate resume-request encoding path defined by the specification.

Why this message matters

RRC Resume Request1 is an alternate resume-request message used by the UE in the resume procedure.

Where this message appears in the call flow

RRC Resume

Call flow position: Alternate first UE message in the resume path.

Typical state: UE is in inactive or suspended state and attempts resume.

Preconditions:

A valid inactive or suspended context exists.

Next likely message: RRC Resume or RRC Reject

Call flow position

Previous message(s): Paging, Resume trigger from upper layers

Next message(s): RRC Resume, RRC Reject

Message direction and transport

Sender and receiver: UE -> gNB

Interface: Uu

Domain: Access-side radio control

Signaling bearer: SRB0

Logical channel: UL-CCCH

Transport / encapsulation: Early resume signaling before restored dedicated context exists

Security context: Sent before full connected context is restored.

Message Structure Overview

The practical role is the same as Resume Request, but the exact encoded variant differs.

ASN.1 for 5G NR - RRC Resume Request1

RRCResumeRequest1 ::= SEQUENCE {
  criticalExtensions CHOICE {
    rrcResumeRequest1 RRCResumeRequest1-IEs,
    ...
  }
}

How to read this ASN.1

In practice, engineers treat this as an alternate resume request variant and correlate it with the same resume procedure outcome.

Decoded Message Dump

UL-CCCH-Message
  message: rrcResumeRequest1

How to read this dump

The main check is that the network recognizes and answers the alternate resume request correctly.

Important Information Elements

IE	Required	Description
`resumeIdentity / variant fields`	Yes	Carries the alternative resume-request content defined by the spec.

Detailed field explanation

`resumeIdentity / variant fields`

Carries the alternative resume-request content defined by the spec.

Presence: Required

What to check in logs and traces

Check whether this variant appears instead of the base resume request.
Correlate it with the same resume acceptance or rejection path.

Common Issues and Troubleshooting

Resume works inconsistently across UE types.

Likely cause: Some traces may use the alternate Resume Request1 path.

What to inspect: Check whether the UE sent RRC Resume Request1 instead of the base resume request.

Next step: Compare the network response to both variants.

Detailed explanation

5G NR - RRC Resume Request1 Explained

RRC Resume Request1 is a 5G NR RRC message reference page for engineers who need to understand what the message carries, where it fits in the procedure, and what to inspect in traces when behavior does not match expectation.

RRC Resume Request1 is an alternate NR RRC resume request message variant used in the resume procedure. Provides the UE with an alternate resume-request encoding path defined by the specification.

What is RRC Resume Request1 in simple terms?

RRC Resume Request1 is the uplink NR RRC message the UE sends to the network when this specific procedure step needs to be requested, reported, or confirmed.

Provides the UE with an alternate resume-request encoding path defined by the specification.

Why this message matters

it directly affects RRC Resume, Inactive-to-Connected Transition
Resume works inconsistently across UE types
Used when the UE follows the RRCResumeRequest1 variant defined for the resume path

Where this message appears in the call flow

RRC Resume Request1 is typically seen during RRC Resume. Engineers usually read it together with the messages just before and just after it so they can tell whether the procedure is progressing normally or drifting into a fallback or failure path.

The UE is usually in in inactive or suspended state and attempts resume when engineers evaluate this message in traces. In the main procedure context, it appears alternate first UE message in the resume path. Before this message appears, the important preconditions are A valid inactive or suspended context exists..

Simplified sequence:

UE                       gNB / Network
|                        |
|<-- Paging -----------|
|--- RRC Resume Request1 ----------->|
|<-- RRC Resume -----------|

Message direction and transport

sender: UE
receiver: gNB
interface: Uu
signaling bearer: SRB0
signaling channel: UL-CCCH
transport type: Early resume signaling before restored dedicated context exists
domain: Access-side radio control
security context: Sent before full connected context is restored.

Important Information Elements

IE	Why it matters
`resumeIdentity / variant fields`	Carries the alternative resume-request content defined by the spec.

Example message dump

UL-CCCH-Message
  message: rrcResumeRequest1

How to read this dump

The main check is that the network recognizes and answers the alternate resume request correctly.

FAQ

How is RRC Resume Request1 different from RRC Resume Request?

It serves the same procedural role but represents an alternate resume-request encoding path defined by the spec.

Summary

RRC Resume Request1 is an alternate NR RRC resume request message variant used in the resume procedure.

Advanced Engineer Notes

This page is mainly useful when engineers compare specification variants or interoperability behavior.

Related message pages

Related Procedures

5G RRC Resume

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.