E1 Application protocol (E1AP) provides the signalling service between the gNB-CU-CP and the gNB-CU-UP of a gNB within an NG-RAN, or between the gNB-CU-CP and the gNB-CU-UP of an en-gNB within an E-UTRAN. The services provided by the E1AP are divided to UE-associated and non UE-associated. The UE-associated services are related to one UE and the non UE-associated services are related to the E1 interface. The E1AP is transferred over SCTP. The E1AP protocol is defined in TS 38.463. The E1AP Client Test Suite has been designed to act as a malicious gNB-CU-CP that sends exceptional messages to the tested entity which is gNB-CU-UP.