QKnxNetIpTunnelingAcknowledgeProxy Class

Detailed Description

Tunneling means that Engineering Tool Software (ETS) sends a single KNX frame in a KNXnet/IP frame and waits until the response arrives or a time-out is reached.

A tunneling request is sent by a KNXnet/IP client to establish a data connection to the endpoint of a KNXnet/IP server for sending a KNX frame. When a KNXnet/IP server receives a tunneling request, it immediately sends a tunneling acknowledgment to the KNXnet/IP client to confirm the reception of the request and then processes the received KNX frame.

A tunneling acknowledgment frame contains the ID and status of the communication channel between a KNXnet/IP client and server, as well as the sequence number of a tunneling request frame.

The server only processes frames with the expected sequence number or one less the expected sequence number. It discards frames with other sequence numbers and does not send a tunneling acknowledgment upon receiving them.

In most programs, this class will not be used directly. Instead, the QKnxNetIpTunnel or QKnxNetIpDeviceManagement class is used to establish a functional connection to a KNXnet/IP server.

The following code sample illustrates how to read the tunneling acknowledgment information sent by a KNXnet/IP client:

auto netIpFrame = QKnxNetIpFrame::fromBytes(...);

const QKnxNetIpTunnelingAcknowledgeProxy proxy(netIpFrame);
if (!proxy.isValid())
    return;

auto chanId = proxy.channelId();
auto seqNum = proxy.sequenceNumber();
auto tunnelStatus = proxy.status();