private VlanId() {
        super(UNTAGGED);
    }
@Test
    public void testEquality() {
        VlanId vlan1 = VlanId.vlanId("None");
        VlanId vlan2 = VlanId.vlanId((short) -10);
        VlanId vlan3 = VlanId.vlanId((short) 100);
        VlanId vlan4 = VlanId.vlanId((short) 200);

        new EqualsTester().addEqualityGroup(VlanId.vlanId(), vlan1)
            .addEqualityGroup(vlan2)
            .addEqualityGroup(vlan3)
            .addEqualityGroup(vlan4)
            .addEqualityGroup(VlanId.vlanId((short) 10))
            .testEquals();

    }