Section: 5.2.2.2.5 Namf_Communication_N1N2MessageSubscribe service operation
Content: Service operation name: Namf_Communication_N1N2MessageSubscribe. Description: An NF can subscribe with the AMF to get notified of a particular N1 message type or a specific N2 information type about the UE. Input, Required: CN NF ID, N1 Message Type Input, Optional: SUPI. Output, Required: None. Output, Optional: None. The consumer NF invokes the Namf_Communication_N1MessageSubscribe service operation (NF ID, N1 message type or N2 information type to subscribe) on the AMF. The consumer NF shall provide a SUPI for UE associated N1 message subscriptions. If the consumer NF is allowed to subscribe for the type of N1/N2 message requested, the AMF creates a binding for the consumer NF to deliver subsequent Namf_Communication_N1MessageNotify or Namf_Communication_N2InfoNotify towards that NF. NOTE: Whether Subscription Ack need a separate message or be realized in the transport layer will be determined in TS 29.518[ 5G System; Access and Mobility Management Services; Stage 3 ]  [18].