The 'mydnet' is symbolic only and can be the same, while the dnet id is unique and locked by the wallet's private key and no one else can manage it.
The node's cryto ID, a.k.a
c2pkh, is obtained from the node's owner (see how). The dnet admin needs to assign an unique virtual IP address. For simplicity, the uniqueness is within the scope of this dnet.
Overlay Cloud (OVC) can be from (what is OVC?):
xxxxxxxxxxxxxxx, this is the default setting, more...
Using Public OVC nodes, the dnet is multi-tenanted with other dnets, while using the private OVC nodes, only multi-tenanted with self dnets.
Overlay Relay (OVR) can be from (what is OVR?):