* Validate network connectivity (Option A): Before adding a node, you must ensure it has valid IP addresses on the management and data networks and can reach the existing MDM cluster. Without this, the "Add Node" wizard will fail.
* Assign the node to an existing Protection Domain (Option B): During the add process, you must explicitly tell the system where this new node belongs. You assign it to a Protection Domain (and optionally a Fault Set). This tells the system which other nodes it should peer with for data mirroring.