An engineer configured the OSPF protocol in the vPC topology.

An engineer configured the OSPF protocol in the vPC topology. During the catastrophic failure of one of the vPC the member switches, the traffic was routed to a black hole. This route was caused by the long convergence time caused by the delay of the of the vPC member switch reboot. After the failure, the engineer rebooted both switches, but the secondary switch powered on before the primary one. It caused all the vPCs to be shut down due to consistency-check violations. Which two features must be used to prevent these situations from happening in the future? (Choose two.)