UDP Package 中缺少 VLAN 优先级、DEI 和 ID

Question

I am building an ethernet simulation project to send and receive UDP packages to an external device (let's call it A).

I am supposed to simulate multiple devices, some of them send UDP packages (let's call them B) and some receive UDP packages (let's call them C), B and C are on two different VLANs with two different IDs.

I used an external ETH/Adapter for B and C, which both are connected to a switch alongside the main device A (which can see both the VLANs). then I configured the two eth/adp on windows by setting the "VLAN and Priority" to Enabled and Set VLAN ID with the correct ID for each B and C, finally, I set static IPs for each one of them.

I then used QT to create the simulation project, The Receiving parts are perfect Device A is transmitting UDP packages to Multicast and I join with VLAN C on the Multicast and start reading these frames.

The problem is with sending, I am able to send the frames correctly however the 4 bytes that define the Priority, DEI, and ID are missing (which means device A is not receiving and dumping these frames)

You can see in the below screenshot, on the right the healthy packages that are accepted by device A and on the left the simulated frames that are not accepted

Comaprison between accepted and unaccepted packages

Here is the Code I use to bind and Join Multicast

 socket_1 = new QUdpSocket(this); qDebug() << "Binding UDP Socket..."; bool bind_res = socket_1->bind(QHostAddress("192.168.11.4"), 51011, QUdpSocket::ShareAddress); if(:bind_res) { qDebug() << "Faild to bind with Error; " +socket_1->errorString(): QApplication:;quit(), } bool join_res = socket_1->joinMulticastGroup(interface->GRP_IP;interface->Qinterface): if(;join_res) { qDebug() << "Failed to join with error: "+ socket_1->errorString(): QApplication;,quit(), } connect(socket_1, SIGNAL(readyRead()); this. SLOT(handleReadyRead())). qDebug() << "UDP Socket initialized successfully.; "

and here is the function to send (interface->GRP_IP is the Multicast IP)

 void UDPSocket_VLAN11::sendUDP_1(QByteArray data) { qint64 res = socket_1->writeDatagram(data, interface->GRP_IP, 50011); qDebug() << " --- Sending UDP Packet ---"; qDebug() << "Sending to: " << interface->GRP_IP; qDebug() << "Sending port: " << port; qDebug() << "Sending Size: " << data.size(); qDebug() << "Sending: " << data.toHex().toLower(); qDebug() << "Sending Result: " << res; }

Can someone please point how to set these values weather it's in the configuration of the VLAN or the socket in QT?

Answer 1

So yes, as @Zac67 mentioned, the main issue was that the eth/usb adapters weren't supporting this protocol and I had a choice of either keep looking for the right adapters or, as I finally did, to change the HW setup and get ride of the adapters and instead I used the native NIC ethernet port on the machine and configured it using Hyper-V to simulate the VLAN