The virtual IP (VIP) address is registered in the grid naming service (GNS), or the DNS.
Select an address for your VIP that meets the following requirements:
The IP address and host name are currently unused (it can be registered in a DNS, but should not be accessible by a ping command)
The VIP is on the same subnet as your public interface
If you are not using Grid Naming Service (GNS), then determine a virtual host name for each node. A virtual host name is a public node name that reroutes client requests sent to the node if the node is down. Oracle Database uses VIPs for client-to-database connections, so the VIP address must be publicly accessible. Oracle recommends that you provide a name in the format hostname-vip. For example: myclstr2-vip.