diff --git a/openair2/F1AP/f1ap_du_rrc_message_transfer.c b/openair2/F1AP/f1ap_du_rrc_message_transfer.c
index ac281af81d..59445d792d 100644
--- a/openair2/F1AP/f1ap_du_rrc_message_transfer.c
+++ b/openair2/F1AP/f1ap_du_rrc_message_transfer.c
@@ -812,6 +812,13 @@ int DU_send_INITIAL_UL_RRC_MESSAGE_TRANSFER(instance_t     instanceP,
                          sdu2P,
                          sdu2_lenP);
   }
+  /* mandatory */
+  /* c6. Transaction ID (integer value) */
+  asn1cSequenceAdd(out->protocolIEs.list, F1AP_InitialULRRCMessageTransferIEs_t, ie6);
+  ie6->id                        = F1AP_ProtocolIE_ID_id_TransactionID;
+  ie6->criticality               = F1AP_Criticality_ignore;
+  ie6->value.present             = F1AP_F1SetupRequestIEs__value_PR_TransactionID;
+  ie6->value.choice.TransactionID = F1AP_get_next_transaction_identifier(f1ap_req(false, instanceP)->gNB_DU_id, f1ap_req(false, instanceP)->gNB_DU_id);
 
   /* encode */
   if (f1ap_encode_pdu(&pdu, &buffer, &len) < 0) {