support for partial responses about dnp3 HOT 3 CLOSED

fair point. if the protocol isn't structured such that chunks are 'skippable', then that's exactly what could happen. i'm mostly playing message passer here, taking dictation. as long as there's an error message returned that can be logged, imho, that should be enough to take further action by either fixing configuration or requesting enhancements.

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I'm not convinced this is a desirable feature. Usually you'd want to configure both sides of the link during commissioning to ensure they're using objects both sides support.

It'd be too easy with this option to think you have a working integration when something is actually pretty broken.

The other issue is that once you encounter something you don't understand, all data past that is lost.

Say that a response contains 4 object headers and your parser knows what a, c, and d are:

<a><b><c><d>

Once the parser hits <b> which it doesn't understand it cannot get past it to read <c> and <d>. This is a limitation in the protocol itself, because reading <c> depends on knowing some static length of objects of type <b>.

If this data is in a response that asks for confirmation, this feature would make the master station confirm it causing all the data to be cleared from the outstation event buffers.

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That's right. You can't skip an unknown object b/c DNP3 isn't tag-length-value.

For what it's worth OpenDNP3 handled unknown objects in the same manner.

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