This read-create InterfaceIndexOrZero is the ifIndex of the single target port associated with this Super-VLAN source port; a value of zero means the source port is instead paired with a redundant pair of ring ports defined in prvtSuperVlanIfRingPortTable. Admins use it to configure simple one-to-one Super-VLAN port forwarding, and changing it from zero to a valid ifIndex automatically deletes any existing ring-port association for that source port. For example, setting this to the ifIndex of a specific uplink port wires that Super-VLAN source directly to a single target port instead of a resilient ring pair.