KNX traffic overload protection

How does the driver prevent communications traffic swamping the KNX twisted pair line?

The KNXnet/IP driver prevents the KNX twisted pair line from being swamped with traffic, by controlling the number of concurrently active Group Address Read Operations and is set by the Max Pending Reads property in the Group Data Manager (see Knx Device/Group Data Manager). The term active in this context, means that a particular Group Address Read Operation has firstly reached the head of the Group Data Operation Queue (see The ‘Read’ queue is full) and secondly, the Communications Stack has sent an L_Data_req message to the KNXnet/IP device and received an L_Data_con reply, but has not yet received a corresponding L_Data_ind message.

The default value of Max Pending Reads is 4 but unfortunately, there is no clear guidance in the KNX Specs as to what an acceptable Max Pending Reads value should be, however having this value too small would not cause a The ‘Read’ queue is full fault.

Image