The installer detects the network interfaces on the cluster member nodes and displays them in the table on this screen. Identify which subnets are public and which subnets are private, and identify any other interfaces that are in use for other purposes, and should not be used for IP addresses within the cluster.
For each interface, in the Interface Type column, identify the interface as Public or Private. If it is an interface that is in use for other purposes, and should not be used by Oracle Clusterware, then mark it as Do Not Use.
The precise configuration you choose for your network depends on the size and use of the cluster you want to configure, and the level of availability you require. If certified Network-attached Storage (NAS) is used for Oracle RAC and this storage is connected through Ethernet-based networks, then you must have a third network interface for storage input/output, and you should mark this interface as Do Not Use so that it is dedicated for use by the NAS.
If you have NAS as your storage option, and you do not have a separate dedicated interface for it, then the lack of a dedicated storage interface can cause performance and stability problems under load. For high capacity clusters with a small number of multiprocessor servers, to ensure high availability, you may want to configure redundant network interfaces to prevent a network interface failure from reducing significantly the overall cluster capacity.