Optimization
/
VoLTE
/
CSSR
/
VoLTE E-RAB Setup
VoLTE
CSSR
VoLTE E-RAB Setup Optimization
Optimize QCI-1 bearer establishment for VoLTE call setup success
Target KPI
≥ 99.5%
VoLTE E-RAB Setup SR
Related Counters
🔢
8
Performance counters
Parameters
⚙️
12
Tunable parameters
KPI Formula
VoLTE_ERAB_SSR = [L.E-RAB.SuccEst.QCI.1 / (L.E-RAB.AttEst.QCI.1 – L.E-RAB.FailEst.X2AP.VoIP)] × 100%
Associated Counters
L.E-RAB.AttEst.QCI.1
VoIP E-RAB setup attempts
L.E-RAB.SuccEst.QCI.1
VoIP E-RAB setup success
L.E-RAB.FailEst.QCI.1
VoIP E-RAB setup failures
L.E-RAB.FailEst.X2AP.VoIP
X2AP related failures (excluded)
Optimization Parameters
Parameter
MO
Default
Recommended
Range
Impact
VoLTEPrioritySwitch
VolteAlgoConfig
OFF
ON
ON/OFF
High
QCI1PreemptionCap
QciPara
NOT_PREEMPT
MAY_PREEMPT
Enum
High
ErabSetupTimer
CellQciPara
3000
5000
1000~30000 ms
Med
DlGbrPriority
CellQciPara
5
1
1~16
Med
Optimization Steps
1
Enable VoLTE Priority
Set VoLTEPrioritySwitch=ON in VolteAlgoConfig to prioritize voice bearers
2
Configure QCI-1 Preemption
Allow QCI-1 bearers to preempt lower priority bearers during congestion
3
Increase E-RAB Setup Timer
Extend timer for edge coverage or high-load scenarios
4
Monitor & Validate
Track L.E-RAB.SuccEst.QCI.1 counter improvement over 24-48 hours
MML Commands
// Check current settings
LST VOLTEALGOCONFIG: LocalCellId=0;
// Modify VoLTE priority
MOD VOLTEALGOCONFIG: LocalCellId=0, VoLTEPrioritySwitch=ON;
// Check QCI parameters
LST QCIPARA: Qci=1;