| Protocol | e1ap | Network | 5g |
|---|---|---|---|
| Spec | 3GPP TS 37.483 | Spec Section | Bearer Context Setup successful outcome and related IE definitions (Release 18 baseline) |
| Direction | gNB-CU-UP -> gNB-CU-CP successfulOutcome | Message Type | UE-associated bearer-context setup confirmation |
| Full message name | 5G E1AP - Bearer Context Setup Response |
|---|---|
| Protocol | E1AP |
| Technology | 5G |
| Direction | gNB-CU-UP -> gNB-CU-CP successfulOutcome |
| Interface | E1 between gNB-CU-CP and gNB-CU-UP |
| Signaling bearer / channel | UE-associated E1AP signaling / SCTP carried E1AP successfulOutcome |
| Typical trigger | The CU-UP has successfully processed Bearer Context Setup Request far enough to keep the bearer-context setup procedure on the success path. |
| Main purpose | Confirms that the CU-UP accepted the requested bearer-context creation and reports the resulting bearer state the CU-CP must use for later user-plane control. |
| Main specification | 3GPP TS 37.483, Bearer Context Setup successful outcome and related IE definitions (Release 18 baseline) |
| Release added | Release 17 |
| Procedures where used | Bearer Context Setup, Initial user-plane bring-up, PDU session resource activation |
Bearer Context Setup Response is the E1AP successful outcome the gNB-CU-UP returns after accepting bearer creation, confirming the CU-UP side UE identity and reporting the resulting bearer and user-plane state.
Confirms that the CU-UP accepted the requested bearer-context creation and reports the resulting bearer state the CU-CP must use for later user-plane control.
Bearer Context Setup Response is the CU-UP telling the CU-CP that bearer creation succeeded and reporting what the CU-UP actually built.
Call flow position: The CU-UP has accepted the setup request and returns the procedure-level success outcome to the CU-CP.
Typical state: The user-plane bearer context now exists at the CU-UP at procedure level.
Preconditions:
Next likely message: Bearer Context Modification Request or later user-plane continuation
Call flow position: The response reports which bearer items and associated user-plane details were created successfully at the CU-UP.
Typical state: The CU-CP must read the returned bearer outcome before assuming the full user-plane model exists exactly as requested.
Preconditions:
Next likely message: Later bearer-context control based on the returned CU-UP state
Previous message(s): Bearer Context Setup Request
Next message(s): Bearer Context Modification Request, Bearer Context Release Command
Security context: Bearer Context Setup Response does not establish NAS security by itself. It reports the outcome of CU-UP bearer creation for the UE.
BearerContextSetupResponse ::= SEQUENCE {
protocolIEs ProtocolIE-Container { {BearerContextSetupResponse-IEs} },
...
}
BearerContextSetupResponse-IEs E1AP-PROTOCOL-IES ::= {
{ gNB-CU-CP UE E1AP ID, mandatory } |
{ gNB-CU-UP UE E1AP ID, mandatory } |
{ System Bearer Context Setup Response, mandatory } |
{ Criticality Diagnostics, optional },
...
}
The response is operationally valuable because it turns requested bearer state into confirmed CU-UP bearer state. Read it as an outcome report, not just as an acknowledgement.
E1AP-PDU
successfulOutcome
procedureCode: id-bearerContextSetup
criticality: reject
value: BearerContextSetupResponse
protocolIEs:
- id: id-gNB-CU-CP-UE-E1AP-ID
value: 0x00004192
- id: id-gNB-CU-UP-UE-E1AP-ID
value: 0x00000087
- id: id-System-BearerContextSetupResponse
value:
pdu-session-list:
- pdu-session-id: 10
drb-setup-list:
- drb-id: 4
qos-flow-list:
- qfi: 9
| IE | Required | Description |
|---|---|---|
gNB-CU-CP UE E1AP ID | Yes | Mandatory CU-CP side UE identifier used to correlate the response with the original setup request. |
gNB-CU-UP UE E1AP ID | Yes | Mandatory CU-UP side UE identifier allocated or confirmed by the CU-UP for the bearer context. |
System Bearer Context Setup Response | Yes | Mandatory bearer result payload that reports the created CU-UP bearer state and associated user-plane outcome. |
Criticality Diagnostics | Optional | Optional protocol-level diagnostics if the CU-UP needs to expose additional processing detail. |
gNB-CU-CP UE E1AP IDMandatory CU-CP side UE identifier used to correlate the response with the original setup request.
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 allocated or confirmed by the CU-UP for the 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.
System Bearer Context Setup ResponseMandatory bearer result payload that reports the created CU-UP bearer state and associated user-plane outcome.
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.
Criticality DiagnosticsOptional protocol-level diagnostics if the CU-UP needs to expose additional processing detail.
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 returned bearer result may not match the original request completely, or later procedures may be using the wrong interpretation of the setup outcome.
What to inspect: Compare the response payload with the original setup request and any subsequent modification command.
Next step: Treat the response as the authoritative CU-UP-side state before debugging downstream traffic.
The request asks the CU-UP to create bearer state. The response reports the bearer state that was actually created.
It is the E1AP successful outcome the gNB-CU-UP sends after bearer-context creation succeeds.
The key fields are the CU-CP UE E1AP ID, the CU-UP UE E1AP ID, and the returned system bearer context response payload.
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.