QKnxNetIpTunnelingRequestProxy Class

Detailed Description

Tunneling means that Engineering Tool Software (ETS) sends a single KNX frame in an 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. A tunneling request frame contains the ID of the communication channel between a KNXnet/IP client and server, the sequence number of the frame, and the KNX frame in the common external message interface (cEMI) format.

The KNXnet/IP server discards frames with sequence numbers that are not the expected sequence numbers or one less the expected 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.

Before sending a tunneling request, the KNXnet/IP client should use QKnxNetIpServerDescriptionAgent and QKnxNetIpServerInfo to check that the server supports the requested connection type and options.

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

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

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

auto chanId = proxy.channelId();
auto seqNum = proxy.sequenceNumber();
auto knxLinkFrame = proxy.cemi();