[lp-wan] augment coupond-ack

[Laurent Toutain <[e-mail]>]

Dear lpwaners,

During the last IETF meeting, it was asked to detach the compound-ack from
the RFC8724 model. I see to ways of doing it.

1) ignore completely the compound-ack from the RFC8724 data model and
augment this model such as:

augment
"/schc:schc/schc:rule/schc:nature/schc:fragmentation/schc:mode/schc:ack-on-error"
{
leaf bitmap-format {
type compound-ack:bitmap-format-type;
when "derived-from(../schc:fragmentation-mode,
'schc:fragmentation-mode-ack-on-error')";
default "compound-ack:bitmap-RFC8724";
description
"How the bitmaps are included in the Ack message.";
}
}


Where we create the leaf and a specific identityref for compound-ack.

2) create the leaf in RFC8724 datamodel but just a default value and just
define the compound ack value in the compound ack model.

Personally, I prefer the first approach, since we cannot guess all the time
what will be extended, but I would like to have your point of view on the
subject.

Laurent