KNXnet/IP Tunnel Connection — Data

Which queue is used for data through the ’Tunnel Connection’?

The Maximum Received Packets Que Size (see Knx Device/Comms Connections/Tunnel Conn) controls the size of the Tunnel Connection’s Data End Point receive queue. All Group Address messages pass through this queue and End Point so it is much busier than the Control End Point (see KNXnet/IP Tunnel Connection — Control). Because it handles more traffic, its default queue size of 50 is larger than that of the Control End Point.

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Unlike the Group Data Operation Queue (see The ‘Read’ queue is full), the necessary size of this queue doesn’t depend on the number and frequency of Control Point polling. Instead it depends on how quickly the KNXnet/IP driver can process incoming messages, which in turn depends on the overall CPU usage in the Platform.

You can monitor the success or otherwise of received data by inspecting the Rx Frames Lost Queue Full counter in the hidden Communications Counters (see Knx Device/Comms Connections/Tunnel Conn/Comms Counters). Depending on the number and frequency of lost Rx Frames, you can try increasing the Maximum Received Packets Que Size in steps of 50, until no more Rx Frames are being lost.

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