| Protocol | rrc | Network | 5g |
|---|---|---|---|
| Spec | 3GPP TS 38.331 | Spec Section | 5.3.7, 6.2.2 |
| Direction | gNB -> UE | Message Type | Connection Recovery |
| Full message name | 5G NR - RRC Reestablishment |
|---|---|
| Protocol | RRC |
| Technology | 5G |
| Direction | gNB -> UE |
| Interface | Uu |
| Signaling bearer / channel | SRB1 / DL-DCCH |
| Typical trigger | Sent when the gNB accepts an RRC Reestablishment Request and continues with recovery. |
| Main purpose | Lets the UE resume protected connected-mode signaling after radio link failure recovery while reusing the recovered context. |
| Main specification | 3GPP TS 38.331, 5.3.7, 6.2.2 |
| Release added | Release 15 |
| Procedures where used | RRC Reestablishment, Radio Link Failure Recovery |
| Related timers | T301 |
RRC Reestablishment is the downlink NR RRC message the network sends when it accepts a reestablishment attempt and provides the recovered connected-mode context.
Lets the UE resume protected connected-mode signaling after radio link failure recovery while reusing the recovered context.
RRC Reestablishment is the network's acceptance message for RLF recovery.
Call flow position: Sent after the network accepts the UE's reestablishment request.
Typical state: UE is recovering from radio link failure.
Preconditions:
Next likely message: RRC Reestablishment Complete
Previous message(s): RRC Reestablishment Request
Next message(s): RRC Reestablishment Complete
Security context: Part of the reestablishment recovery path and tied to recovered security context.
RRCReestablishment ::= SEQUENCE {
criticalExtensions CHOICE {
rrcReestablishment RRCReestablishment-IEs,
...
}
}
The practical checks are whether the reestablishment was accepted and what recovered configuration was sent back.
DL-DCCH-Message
message: rrcReestablishment
radioBearerConfig: present
| IE | Required | Description |
|---|---|---|
radioBearerConfig | Yes | Recovered configuration the UE uses to rebuild the connected radio context. |
nextHopChainingCount | Optional | Security-related count used during recovery handling. |
radioBearerConfigRecovered configuration the UE uses to rebuild the connected radio 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.
nextHopChainingCountSecurity-related count used during recovery handling.
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.
Likely cause: The recovered context may be incomplete or inconsistent.
What to inspect: Check the reestablishment payload and the later complete message.
Next step: Correlate with the radio failure cause and follow-on RRC messages.
The UE normally answers with RRC Reestablishment Complete if recovery succeeds.
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.