NGAP
NG Application Protocol
NGAP is found on the N2 reference point between the gNB and the AMF (Core Access and Mobility and Management Function) in order to support both UE and non UE associated services. This includes operations such as configuration updates, UE context transfer, PDU Session resource management and also support for mobility procedures. NGAP is also used to convey downlink and uplink NAS (Non Access Stratum) messages as a payload, as well as support CM Idle and CM Connected operations such as Paging and UE Context release.