Correctly handling ACK_OVERFLOW - E1.20 RDM (Remote Device Management) Protocol Forums

nomis52 · September 5th, 2010

Here's a related problem: The standard states "The responder shall abort a partial transfer of overflow data for a PID when receiving a command
for a different PID before the overflow data transfer is complete."

It says nothing however about what happens if the src UID differs. In multi-controller setups like E1.33 we're going to need to be careful to ensure one of the following:

i) other get/set messages can't be interleaved when an ACK_OVERFLOW sequence is occurring on the DMX side
ii) if interleaving is allowed, the responders need to track the transfer status per src UID and only reset if a different PID is received from the same src UID.

I'll have a guess that no one has designed their responders to handle case ii) so I think we'll have to go with i). This means that gateways are going to have to buffer the entire message.

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September 5th, 2010	#4
nomis52 Task Group Member Join Date: May 2010 Location: San Franciscio Posts: 57	Here's a related problem: The standard states "The responder shall abort a partial transfer of overflow data for a PID when receiving a command for a different PID before the overflow data transfer is complete." It says nothing however about what happens if the src UID differs. In multi-controller setups like E1.33 we're going to need to be careful to ensure one of the following: i) other get/set messages can't be interleaved when an ACK_OVERFLOW sequence is occurring on the DMX side ii) if interleaving is allowed, the responders need to track the transfer status per src UID and only reset if a different PID is received from the same src UID. I'll have a guess that no one has designed their responders to handle case ii) so I think we'll have to go with i). This means that gateways are going to have to buffer the entire message.