5G • Core Network
CM-IDLE
IDLE Connection Management State
Connection Management state where no active N1 signaling connection exists between UE and AMF.
Technical Explanation
In CM-IDLE state, the UE has no active radio signaling bearer (RRC_IDLE or RRC_INACTIVE). The AMF does not maintain an active N2 connection. To deliver incoming downlink data, the AMF must initiate Paging across the UE's registered Tracking Area.
Key Functions
- No active N1 NAS or N2 control plane connection exists
- UE radio is asleep in DRX, reducing battery power consumption
- Downlink data arrival prompts AMF to initiate Tracking Area Paging
Specifications
3GPP TS 23.501, TS 24.501
Interfaces
N1N2
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