cmEthernetTrafficPortTagFrameControl is a read-write setting defining whether a c-tag/s-tag frame is allowed to pass through this port, available only when the port's admitted frame policy (AFP) is set to Tagged. An administrator uses this to control whether already-tagged customer frames are accepted onto a port expecting tagged input, rejecting untagged frames that don't match the configured tagging policy. For example, a port provisioned to only accept pre-tagged customer traffic would use this object to explicitly allow c-tag/s-tag frames through rather than silently dropping them due to the Tagged AFP policy.