By using GNS with sub-domain ,we will get dynamic allocation of VIP's & Scan IP from DNS sub-domain.This makes easier addition & deletion of nodes in the cluster.
But I have few doubt in GNS configuration without sub-domain. In this configuration just GNS vip entry to be made in DNS to install Oracle 12C RAC with ASM flex. I would need help to understand following.
1. What is the role of GNS vip without subdomain?
2. What is the necessity of GNS vip with ASM flex installation.