Subject: [lp-wan] Ticket #11: ACK format

From: Ana Minaburo <[email-masked]>
Date: Mon, 26 Feb 2018 22:07:52 +0100

Does Padding is needed for ACK?

Ana: Yes because RuleID and bitmap are not always multiple of 8 bits
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padding in ACK? Laurent

Edgar: comment about the whole padding thing. NB-IOT does not need byte
alignement of the payload. There is padding a Layer 2 anyway. Does padding
need to be here, or should be left to the technology dcument?
JCZ: agree to remove it from the general SCHC document, and leave it to the
technology documents.
Ana: several months ago, decided that padding was best put at the end.
Edgar: padding here is to achieve byte alignement. Also filling a transport
block. leave the latter to the L2. The former may not be needed on some
technologies.
Carles: the SCHC doc could mention the two options (padding between header
and payload or at the end). Leave to the tech document to select.
Edgar: rather have only one specified, and activate it or not. Otherwise
interop will be hard, especially multi-RAT networks.
Laurent: in LoRa? <https://trac.ietf.org/trac/lpwan/wiki/LoRa>, we
(Acklio?) use the FPort byte to carry the Rule ID, in one full byte. Some
form of padding!
Laurent:
Ana: suggests to have a DEFAULT specification in the SCHC document, and
leave it to the technology document to specify differently if it wants!