fix: notify PCF with AN_CH_COR trigger after N2 handover completes#201
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timyl wants to merge 1 commit into
Open
fix: notify PCF with AN_CH_COR trigger after N2 handover completes#201timyl wants to merge 1 commit into
timyl wants to merge 1 commit into
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After N2 handover, SMF receives HoState=COMPLETED from AMF along with the UE's post-handover location. SMF now: 1. Saves the incoming ueLocation to smContext 2. After PFCP path-switch succeeds, asynchronously notifies PCF with AN_CH_COR trigger and the new userLocationInfo (TS 29.512 §5.6.3) 3. Applies the returned SmPolicyDecision (e.g. AMBR update) and sends a second PFCP modification to enforce updated QoS at the UPF The PCF notification is async to avoid blocking the 200 OK response to AMF, which would delay UEContextReleaseCommand to the source gNB. Depends on: free5gc/amf#204
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Summary
After N2 handover completes, SMF now reports the UE's new location to
PCF using the
AN_CH_COR(Access Network Change Correlation) trigger,as required by 3GPP TS 29.512 §5.6.3.
Changes
internal/sbi/consumer/pcf_service.goAdded
SendSMPolicyAssociationUpdateByLocationChange()which sendsSmPolicyUpdateContextDatawith:repPolicyCtrlReqTriggers: [AN_CH_COR]userLocationInfo: UE's post-handover locationinternal/sbi/processor/pdu_session.goHoState_COMPLETEDhandler: saveueLocationfrom AMF requestinto
smContext.UeLocationSessionUpdateSuccess(after PFCP path-switch): launch asyncgoroutine to notify PCF and apply returned policy decision via PFCP
The goroutine is async to avoid blocking the 200 OK to AMF — a sync
call would delay
UEContextReleaseCommandto the source gNB and causeDL traffic outage of ~3 minutes in testing.
Related PR
Requires AMF change to populate
ueLocationin HoState=COMPLETED:free5gc/amf#204
Testing
Verified with free5gc v4.2.0 + UERANSIM + OAI rfsim + vendor PCF