usdVlanSubIfVlanUntagged 1.3.6.1.4.1.4874.2.2.34.1.4.2.1.3

When VLANs are enabled, this allows tagged frames to be received, while transmitted frames remain untagged. This can only be enabled when the usdVlanSubIfVlanId field is zero. Cannot be changed if the vlan subinterface has upper bindings.