The present document specifies the standards for Signalling Transport to be used across the F1 interface. The F1 interface provides means for interconnecting a gNB-CU and a gNB-DU of a gNB within an NG-RAN@ or for interconnecting a gNB-CU and a gNB-DU of an en-gNB within an E-UTRAN. The present document describes how the F1AP signalling messages are transported over F1.