This read-create object specifies which customer VLAN IDs (CVLANs) of the inner tag on a QinQ frame map to this entry, accepting a specific VLAN ID, a range like '100-120', the keyword 'untagged', or 'default' to match anything unmatched. An admin configures this when building QinQ VLAN mapping rules, defining which customer-side inner VLANs should be mapped to the outer service-provider VLAN in this row. Setting it to '100-120' would map all customer VLANs from 100 through 120 into this mapping entry.