LTE RRC Connection Reestablishment

Message Fact Sheet

Protocol	lte-rrc	Network	lte
Spec	3GPP TS 36.331	Spec Section	5.3.7, 6.2.2, Annex B
Direction	eNodeB -> UE	Message Type	Connection Recovery

Full message name	LTE RRC Connection Reestablishment
Protocol	LTE-RRC
Technology	LTE
Direction	eNodeB -> UE
Interface	Uu
Signaling bearer / channel	SRB0 / DL-CCCH
Typical trigger	The network accepts RRCConnectionReestablishmentRequest and continues the LTE recovery path.
Main purpose	Continues the LTE re-establishment path by restoring the connected radio control context after the network accepts the UE recovery request.
Main specification	3GPP TS 36.331, 5.3.7, 6.2.2, Annex B
Release added	Release 8
Procedures where used	RRC Re-establishment, Radio Link Failure Recovery, Handover Failure Recovery

What is LTE RRC Connection Reestablishment in simple terms?

Downlink LTE RRC message sent by the network to accept re-establishment and rebuild the connected signaling context after a recoverable failure.

Continues the LTE re-establishment path by restoring the connected radio control context after the network accepts the UE recovery request.

Why this message matters

RRCConnectionReestablishment is the LTE network saying that recovery is accepted and the broken connected context can be rebuilt.

Where this message appears in the call flow

Radio link failure recovery

Call flow position: Network acceptance message that continues the LTE re-establishment path after the UE request.

Typical state: UE is in the recovery branch and is rebuilding a connected context.

Preconditions:

RRCConnectionReestablishmentRequest was accepted.
The earlier UE context is still recoverable.

Next likely message: RRCConnectionReestablishmentComplete

Handover failure recovery

Call flow position: Recovery-accept message used after a failed mobility path when LTE re-establishment is allowed to continue.

Typical state: UE is recovering from a failed connected mobility attempt.

Preconditions:

The failed mobility path still allows recovery.
The network could correlate and accept the recovery request.

Next likely message: RRCConnectionReestablishmentComplete

Call flow position

Previous message(s): RRCConnectionReestablishmentRequest

Next message(s): RRCConnectionReestablishmentComplete, Later recovered connected-mode LTE RRC signaling

Message direction and transport

Sender and receiver: eNodeB -> UE

Interface: Uu

Domain: Access-side radio control recovery

Signaling bearer: SRB0

Logical channel: DL-CCCH

Transport / encapsulation: RRC over CCCH during re-establishment before the dedicated connected context is fully restored

Security context: Sent during recovery of a previously broken connected context, before the restored dedicated signaling path fully resumes.

Message Structure Overview

RRCConnectionReestablishment is the network acceptance step in the LTE recovery branch.
Its practical meaning comes from the fact that recovery was accepted and the connected context is being rebuilt.
The most useful follow-on check is whether the UE completes recovery successfully.

ASN.1 for LTE RRC Connection Reestablishment

RRCConnectionReestablishment ::= SEQUENCE {
  rrc-TransactionIdentifier RRC-TransactionIdentifier,
  criticalExtensions CHOICE {
    c1 CHOICE {
      rrcConnectionReestablishment-r8 RRCConnectionReestablishment-r8-IEs,
      spare3 NULL,
      spare2 NULL,
      spare1 NULL
    },
    criticalExtensionsFuture SEQUENCE {}
  }
}

RRCConnectionReestablishment-r8-IEs ::= SEQUENCE {
  radioResourceConfigDedicated RadioResourceConfigDedicated,
  nextHopChainingCount         NextHopChainingCount,
  nonCriticalExtension         RRCConnectionReestablishment-v8a0-IEs OPTIONAL
}

How to read this ASN.1

The message is mainly read as recovery acceptance plus the dedicated configuration needed to continue the restored connected path.

LTE RRC Connection Reestablishment - Example Dump

DL-CCCH-Message
  message c1 : rrcConnectionReestablishment : {
    rrc-TransactionIdentifier 2,
    criticalExtensions c1 : rrcConnectionReestablishment-r8 : {
      radioResourceConfigDedicated present,
      nextHopChainingCount 3
    }
  }

How to read this dump

Start by confirming that the network accepted recovery rather than rejecting it.
radioResourceConfigDedicated is the key payload used to restore the connected context.
The next useful read is whether the UE answers with RRCConnectionReestablishmentComplete.

Important Information Elements

IE	Required	Description
`rrc-TransactionIdentifier`	Yes	Transaction identifier used to correlate the recovery exchange.
`radioResourceConfigDedicated`	Yes	Dedicated radio configuration used to rebuild the recovered connected context.
`nextHopChainingCount`	Optional	Security-related counter context used in the recovery path.
`nonCriticalExtension`	Optional	Release-extension branch for later additions.

Detailed field explanation

`rrc-TransactionIdentifier`

Transaction identifier used to correlate the recovery exchange.

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.

`radioResourceConfigDedicated`

Dedicated radio configuration used to rebuild the recovered connected context.

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.

`nextHopChainingCount`

Security-related counter context used in the recovery path.

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`

Release-extension branch for later additions.

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 RRCConnectionReestablishmentRequest.
Check the rebuilt dedicated radio configuration.
Verify whether the UE completes recovery with RRCConnectionReestablishmentComplete.
Correlate the recovered behavior with the earlier failure cause.
If recovery still fails later, move forward into the post-accept path.

Common Issues and Troubleshooting

The network accepts re-establishment but the UE still does not recover.

Likely cause: The rebuilt connected configuration may still fail, or the later completion step may not happen.

What to inspect: Check radioResourceConfigDedicated, the following completion message, and the recovered radio behavior.

Next step: Continue into the post-accept recovery path instead of assuming acceptance solved the issue.

Re-establishment is accepted after handover failure, but service still drops.

Likely cause: The recovery path may continue, but the restored context may still be unstable.

What to inspect: Read the accept message together with the earlier mobility failure and the following complete message.

Next step: Treat this as recovered-but-unstable behavior rather than a pure accept/reject issue.

The message is present but later release follows quickly.

Likely cause: Recovery may have been accepted formally but not held successfully.

What to inspect: Check the rebuilt dedicated configuration and the immediate post-recovery signaling.

Next step: Compare with a known-good re-establishment success path.

LTE / 5G / Variant Comparison

Compared with RRCConnectionReestablishmentRequest

RRCConnectionReestablishmentRequest is the UE recovery request. RRCConnectionReestablishment is the network acceptance that continues recovery.

Compared with RRCConnectionSetup

RRCConnectionSetup creates a fresh connected context. RRCConnectionReestablishment restores a previously broken one.

FAQ

What is RRCConnectionReestablishment in LTE?

It is the downlink LTE RRC message the network sends to accept re-establishment and continue recovery of a broken connected context.

What comes after RRCConnectionReestablishment?

The UE normally responds with RRCConnectionReestablishmentComplete.

What should I inspect first in RRCConnectionReestablishment?

Start with whether recovery was accepted, then inspect the rebuilt dedicated configuration and the following completion step.

How is it different from RRCConnectionSetup?

RRCConnectionSetup creates a new connection. RRCConnectionReestablishment restores an earlier one after failure.

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.