An Open radio access network (ORAN) configured for accessing a 5G Core network to provide voice and data services to one or more mobile terminals, includes radio units (RUs), distributed units (DUs) and a centralized unit (CU) pool. The ORAN is configured such that each DU is configured to be associated concurrently to a primary CU and a secondary CU, both selected from the CU pool according to predetermined criteria. Upon occurrence of a predetermined event, the DU switches the secondary CU to become the primary CU, without resulting an outage in the ORAN.