FrigoTunnel is a simple network protocol for auto-discovery and multicast communication
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A small library to get a simple communication channel between devices on a same network. Just set a name to each device, and you can send messaes to them without worrying about their IP address.

Typical Use

Here is some short snippet that demonstrates how to send and receive messages using FrigoTunnel.

FrigoTunnel tunnel("my-host");

connect(&tunnel, &FrigoTunnel::gotMessage, [=](const QJsonObject &message) {
  qDebug() << "inbound message" << message;

QJsonObject content;
content["foo"] = "bar";

FrigoMessage message(content);"some-other-host");

FrigoPacket packet(&message);

In the above example, the message is sent to the host some-other-host, however you could also broadcast it using the special hostname *.


Basically, each node listens to the same UDP multicast address ( and waits for messages addressed to them to come.

To improve reliability, there is also node discovery system. Each node broadcasts its name every few seconds (a random interval, between 10 and 30 seconds), and upon receiving a name, a TCP socket is opened.

When a regular message is sent, it is sent first through the UDP socket, and then through each currently open TCP socket, in case the UDP packet didn't make it.


Version 1.0.0

  • Initial Public Version
  • Can send/receive reliable unicast or multicast messages


This project is written by Rémy Sanchez <>, and is available under the terms of the WTFPL license, which is included in this repository.