cmEthernetTrafficPortEgressVlanTrunkingEnabled is a read-write boolean that enables or disables VLAN trunking on the egress direction of this Ethernet port, applicable only for connection-oriented EVPL service. An administrator disables this when a customer expects to receive untagged Ethernet frames, since disabling VLAN trunking strips all VLAN tags before the traffic leaves the port, while enabling it preserves the customer's original VLAN tags end-to-end. For example, an EVPL service handing off to a customer device that cannot process VLAN tags would have this object disabled so all tags are removed before the frames reach that device.