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Old January 8th, 2020   #2
Task Group Member
Join Date: Aug 2008
Posts: 373

Yes, this is new payload structure for RDM.

Up until this point all of the responses that could generate an ACK_OVERFLOW consisted of a single repeating data structure without any header.

ENDPOINT_LIST and ENDPOINT_RESPONDERS now have a header, followed by a repeating data structure. This is different, and (as you say) complicates parsing.

The latest public-review draft of E1.37-5 also has at least one PID with a similar structure.

However, it's always been a good idea for the controller to receive and reassemble all of the packets in an ACK_OVERFLOW sequence before parsing the responses. Most responders would split the responses between records, but that's not actually required anywhere in the standard.

It's valid for a responder to split a long response partway through one of the repeating data structures. For example, with PROXIED_DEVICES, you could have the first 4 bytes of a UID in the one packet and the last 2 bytes in the next packet.

In My Personal Opinion splitting one record across two packets is a bad idea, and I strongly discourage it. But it can happen, and responders should be able to handle it.
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