| Protocol | e1ap | Network | 5g |
|---|---|---|---|
| Spec | 3GPP TS 37.483 | Spec Section | Bearer Context Release procedure and related IE definitions (Release 18 baseline) |
| Direction | gNB-CU-CP -> gNB-CU-UP initiatingMessage | Message Type | UE-associated bearer-context release control |
| Full message name | 5G E1AP - Bearer Context Release Command |
|---|---|
| Protocol | E1AP |
| Technology | 5G |
| Direction | gNB-CU-CP -> gNB-CU-UP initiatingMessage |
| Interface | E1 between gNB-CU-CP and gNB-CU-UP |
| Signaling bearer / channel | UE-associated E1AP signaling / SCTP carried E1AP initiatingMessage |
| Typical trigger | The CU-CP decides that the CU-UP bearer context is no longer required because of release, handover cleanup, failure recovery, or another bearer-teardown event. |
| Main purpose | Tells the CU-UP to release bearer state for one UE so user-plane resources can be cleaned up under CU-CP control. |
| Main specification | 3GPP TS 37.483, Bearer Context Release procedure and related IE definitions (Release 18 baseline) |
| Release added | Release 17 |
| Procedures where used | Bearer context release, Mobility cleanup, Failure recovery teardown |
Bearer Context Release Command is the E1AP message the gNB-CU-CP sends to the gNB-CU-UP to release the existing bearer context for one UE when the user-plane branch is no longer needed or must be cleaned up.
Tells the CU-UP to release bearer state for one UE so user-plane resources can be cleaned up under CU-CP control.
Bearer Context Release Command is the CU-CP telling the CU-UP to tear down the UE's bearer context.
Call flow position: The CU-CP no longer needs the CU-UP bearer branch for the UE and orders release.
Typical state: The CU-UP still holds the bearer state, but the control plane has decided that the user-plane branch should be removed.
Preconditions:
Next likely message: Bearer Context Release Complete
Call flow position: The release command is used to clean up CU-UP bearer state after the control plane decides that the current bearer branch should end.
Typical state: The CU-UP must remove bearer resources that should not survive the current release decision.
Preconditions:
Next likely message: Bearer Context Release Complete
Previous message(s): Bearer Context Setup Response, Bearer Context Modification Request
Next message(s): Bearer Context Release Complete
Security context: Bearer Context Release Command does not create or update security. It removes CU-UP bearer state for the targeted UE.
BearerContextReleaseCommand ::= SEQUENCE {
protocolIEs ProtocolIE-Container { {BearerContextReleaseCommand-IEs} },
...
}
BearerContextReleaseCommand-IEs E1AP-PROTOCOL-IES ::= {
{ gNB-CU-CP UE E1AP ID, mandatory } |
{ gNB-CU-UP UE E1AP ID, mandatory } |
{ Cause, mandatory } |
{ Bearer Context Status Change, optional },
...
}
The release command is structurally smaller than setup or modification because its main job is to identify the existing bearer context and explain why it should be removed.
E1AP-PDU
initiatingMessage
procedureCode: id-bearerContextRelease
criticality: reject
value: BearerContextReleaseCommand
protocolIEs:
- id: id-gNB-CU-CP-UE-E1AP-ID
value: 0x00004192
- id: id-gNB-CU-UP-UE-E1AP-ID
value: 0x00000087
- id: id-Cause
value:
radioNetwork: normal-release
- id: id-BearerContextStatusChange
value: released
| IE | Required | Description |
|---|---|---|
gNB-CU-CP UE E1AP ID | Yes | Mandatory CU-CP side UE identifier used to correlate the release command with the existing bearer context. |
gNB-CU-UP UE E1AP ID | Yes | Mandatory CU-UP side UE identifier used to identify the bearer context to be released. |
Cause | Yes | Mandatory release reason explaining why the CU-CP is ordering bearer-context teardown. |
Bearer Context Status Change | Optional | Optional status-oriented context that can help describe the bearer state transition associated with the release command. |
gNB-CU-CP UE E1AP IDMandatory CU-CP side UE identifier used to correlate the release command with the existing bearer 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.
gNB-CU-UP UE E1AP IDMandatory CU-UP side UE identifier used to identify the bearer context to be released.
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.
CauseMandatory release reason explaining why the CU-CP is ordering bearer-context teardown.
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.
Bearer Context Status ChangeOptional status-oriented context that can help describe the bearer state transition associated with the release command.
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: A Bearer Context Release Command may have been sent because the control plane decided to tear down the branch.
What to inspect: Check the release cause and correlate it with preceding mobility, rejection, or teardown procedures.
Next step: Treat the release command as the authoritative control-plane teardown instruction for the CU-UP branch.
Modification changes an active bearer context in place. Release tears the bearer context down.
It is the E1AP message the gNB-CU-CP sends to the gNB-CU-UP to release an existing bearer context for one UE.
The core mandatory fields are the CU-CP UE E1AP ID, the CU-UP UE E1AP ID, and Cause.
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.