/// <summary>
/// Sets the VLAN mask for the specified port.
/// </summary>
public void SetVlanMask(Port port, Byte[] mask) {
    if (mask.Length != 2)
        throw new ArgumentException("mask must be exactly 2 bytes.");

    try {
        lock (objLock) {
            if (blnConnected || Connect()) {
                Log("Set VLAN data for port: " + port + "Value: " + BitConverter.ToString(mask));

                Int32 intReturn = 0;
                // enable MDIO
                Byte[] writeBytes = new Byte[] { 0x02, 0x01 };
                intReturn = WriteRequest((Byte)Device.Switch, writeBytes, 2);
                if (intReturn != CP2112_DLL.HID_SMBUS_SUCCESS) {
                    LogUtility.Log.Error("SetVlanMask error: WriteRequest(" + ((Byte)Device.Switch).ToString("X2") + ", " + BitConverter.ToString(writeBytes) + ", 2) == " + intReturn.ToString() + " (Enable MDIO)");
                    return;
                }
                // address switch
                writeBytes = new Byte[] { 0x5F, GetSwitchPortDevice(port) }; // GetSwitchPortDevice() returns either 0x01 or 0x02 depending on which switch that port is on
                intReturn = WriteRequest((Byte)Device.Switch, writeBytes, 2);
                if (intReturn != CP2112_DLL.HID_SMBUS_SUCCESS) {
                    LogUtility.Log.Error("SetVlanMask error: WriteRequest(" + ((Byte)Device.Switch).ToString("X2") + ", " + BitConverter.ToString(writeBytes) + ", 2) (address switch)");
                    return;
                }

                byte bytPort = (byte)(GetSwitchPortRegister(port) + 0x10);
                ushort smiCommand = (ushort)(1 << 15 | 1 << 12 | 1 << 10 | bytPort << 5 | 0x06); // 0x06 is the VLAN register
                writeBytes = new Byte[3];
                writeBytes[0] = 0x61;
                writeBytes[1] = mask[1];
                writeBytes[2] = mask[0];
                intReturn = WriteRequest((Byte)Device.Switch, writeBytes, 3); // write mask first
                if (intReturn != CP2112_DLL.HID_SMBUS_SUCCESS) {
                    LogUtility.Log.Error("SetVlanMask error: WriteRequest(" + ((Byte)Device.Switch).ToString("X2") + ", " + BitConverter.ToString(writeBytes) + ", 3) (write port vlan data)");
                    return;
                }

                writeBytes[0] = 0x60;
                writeBytes[1] = (byte)(smiCommand & 0xFF); // lsb
                writeBytes[2] = (byte)(smiCommand >> 8); // msb
                intReturn = WriteRequest((Byte)Device.Switch, writeBytes, 3); // write SMI command
                if (intReturn != CP2112_DLL.HID_SMBUS_SUCCESS) {
                    LogUtility.Log.Error("SetVlanMask error: WriteRequest(" + ((Byte)Device.Switch).ToString("X2") + ", " + BitConverter.ToString(writeBytes) + ", 3) (write port vlan data)");
                    return;
                }
            }
        }
    } catch (Exception ex) {
        LogUtility.Log.Error("SetVlanMask exception", ex);
    } finally { Disconnect(); }
}

/// <summary>
/// Sets the VLAN scenario 0 (No VLANs).  All ports will be able to
/// communicate with all other ports.
/// </summary>
public Boolean SetVlanScenario0() {
    try {
        lock (objLock) {
            SetVlanMask(Port.Port01,  new Byte[] { 0x07, 0xBF });
            SetVlanMask(Port.Port02,  new Byte[] { 0x07, 0x7F });
            SetVlanMask(Port.Port03,  new Byte[] { 0x07, 0xEF });
            SetVlanMask(Port.Port04,  new Byte[] { 0x07, 0xDF });
            SetVlanMask(Port.Port05,  new Byte[] { 0x07, 0xFB });
            SetVlanMask(Port.Port06,  new Byte[] { 0x07, 0xF7 });
            SetVlanMask(Port.Port07,  new Byte[] { 0x07, 0xFE });
            SetVlanMask(Port.Port08,  new Byte[] { 0x07, 0xFD });
            SetVlanMask(Port.Port09,  new Byte[] { 0x07, 0xBF });
            SetVlanMask(Port.Port10,  new Byte[] { 0x07, 0x7F });
            SetVlanMask(Port.Port11,  new Byte[] { 0x07, 0xEF });
            SetVlanMask(Port.Port12,  new Byte[] { 0x07, 0xDF });
            SetVlanMask(Port.Port13,  new Byte[] { 0x07, 0xFB });
            SetVlanMask(Port.Port14,  new Byte[] { 0x07, 0xF7 });
            SetVlanMask(Port.Port15,  new Byte[] { 0x07, 0xFE });
            SetVlanMask(Port.Port16,  new Byte[] { 0x07, 0xFD });
            SetVlanMask(Port.Uplink1, new Byte[] { 0x06, 0xFF });
            SetVlanMask(Port.Uplink2, new Byte[] { 0x06, 0xFF });
            SetVlanMask(Port.Switch1, new Byte[] { 0x05, 0xFF });
            SetVlanMask(Port.Switch2, new Byte[] { 0x03, 0xFF });
            SetVlanMask(Port.COM_X,   new Byte[] { 0x05, 0xFF });
            SetVlanMask(Port.DSP,     new Byte[] { 0x03, 0xFF });
        }
    } catch {
        return false;
    }
    return true;
}

/// <summary>
/// Sets the VLAN scenario 1. Uplink 2 is WAN port, all others
/// are on the same VLAN.
/// </summary>
public Boolean SetVlanScenario1() {
    try {
        lock (objLock) {
            SetVlanMask(Port.Port01,  new Byte[] { 0x07, 0xBF });
            SetVlanMask(Port.Port02,  new Byte[] { 0x07, 0x7F });
            SetVlanMask(Port.Port03,  new Byte[] { 0x07, 0xEF });
            SetVlanMask(Port.Port04,  new Byte[] { 0x07, 0xDF });
            SetVlanMask(Port.Port05,  new Byte[] { 0x07, 0xFB });
            SetVlanMask(Port.Port06,  new Byte[] { 0x07, 0xF7 });
            SetVlanMask(Port.Port07,  new Byte[] { 0x07, 0xFE });
            SetVlanMask(Port.Port08,  new Byte[] { 0x07, 0xFD });
            SetVlanMask(Port.Port09,  new Byte[] { 0x07, 0xBF });
            SetVlanMask(Port.Port10,  new Byte[] { 0x07, 0x7F });
            SetVlanMask(Port.Port11,  new Byte[] { 0x07, 0xEF });
            SetVlanMask(Port.Port12,  new Byte[] { 0x07, 0xDF });
            SetVlanMask(Port.Port13,  new Byte[] { 0x07, 0xFB });
            SetVlanMask(Port.Port14,  new Byte[] { 0x07, 0xF7 });
            SetVlanMask(Port.Port15,  new Byte[] { 0x07, 0xFE });
            SetVlanMask(Port.Port16,  new Byte[] { 0x07, 0xFD });
            SetVlanMask(Port.Uplink1, new Byte[] { 0x06, 0xFF });
            SetVlanMask(Port.Uplink2, new Byte[] { 0x02, 0x00 }); // uplink 2 can only communicate with COM X
            SetVlanMask(Port.Switch1, new Byte[] { 0x05, 0xFF });
            SetVlanMask(Port.Switch2, new Byte[] { 0x03, 0xFF });
            SetVlanMask(Port.COM_X,   new Byte[] { 0x05, 0xFF });
            SetVlanMask(Port.DSP,     new Byte[] { 0x03, 0xFF });
        }
    } catch {
        return false;
    }
    return true;
}

/// <summary>
/// Sets the VLAN scenario 2. Uplink 1 is on a VLAN with ports 9-16
/// and Uplink 2 is on a VLAN with ports 1-8.
/// </summary>
public Boolean SetVlanScenario2() {
    try {
        lock (objLock) {
            // ports 1-8 can only talk to ComX and Switch2 and each other, but not Uplink2
            SetVlanMask(Port.Port01,  new Byte[] { 0x06, 0xBF }); // 0110-1011-1111 (06-BF)
            SetVlanMask(Port.Port02,  new Byte[] { 0x06, 0x7F });
            SetVlanMask(Port.Port03,  new Byte[] { 0x06, 0xEF });
            SetVlanMask(Port.Port04,  new Byte[] { 0x06, 0xDF });
            SetVlanMask(Port.Port05,  new Byte[] { 0x06, 0xFB });
            SetVlanMask(Port.Port06,  new Byte[] { 0x06, 0xF7 });
            SetVlanMask(Port.Port07,  new Byte[] { 0x06, 0xFE });
            SetVlanMask(Port.Port08,  new Byte[] { 0x06, 0xFD });
            SetVlanMask(Port.Port09,  new Byte[] { 0x06, 0xBF });
            SetVlanMask(Port.Port10,  new Byte[] { 0x06, 0x7F });
            SetVlanMask(Port.Port11,  new Byte[] { 0x06, 0xEF });
            SetVlanMask(Port.Port12,  new Byte[] { 0x06, 0xDF });
            SetVlanMask(Port.Port13,  new Byte[] { 0x06, 0xFB });
            SetVlanMask(Port.Port14,  new Byte[] { 0x06, 0xF7 });
            SetVlanMask(Port.Port15,  new Byte[] { 0x06, 0xFE });
            SetVlanMask(Port.Port16,  new Byte[] { 0x06, 0xFD });
            SetVlanMask(Port.Uplink1, new Byte[] { 0x06, 0x00 }); // uplink 1 can only talk to Switch1
            SetVlanMask(Port.Uplink2, new Byte[] { 0x06, 0x00 }); // 0110-0000-0000 (06-00) uplink 2 can only talk to COM X and Switch2
            SetVlanMask(Port.Switch1, new Byte[] { 0x05, 0xFF });
            SetVlanMask(Port.Switch2, new Byte[] { 0x03, 0xFF });
            SetVlanMask(Port.COM_X,   new Byte[] { 0x05, 0xFF });
            SetVlanMask(Port.DSP,     new Byte[] { 0x03, 0xFF });
        }
    } catch {
        return false;
    }
    return true;
}