The present disclosure pertains to improving resilience to single event upsets (“SEUs”) in a software-defined network (“SDN”). In one embodiment, a system may include a communications interface to receive and transmit a data packet. A primary data flow repository may store a plurality of communication flows to be used to route the data packet. A secondary data flow repository may store a subset of communication flows to be used to route a data packet. A system may search the plurality of communication flows in the primary data flow repository based on a criteria associated with the data packet. If no communication flow satisfies the criteria, a secondary data flow repository may be searched. The data packet may be routed according to a communication flow in the secondary data flow repository. The communication flow from the secondary data flow repository may be duplicated in the primary data flow repository.