[core] Comments on draft-ietf-core-yang-cbor-06

[Robert Wilton <[e-mail]>]

Hi,

I've read this draft, and think that it is well written.

There is one area of the draft that is somewhat unclear to me when using 
SID encodings:  Is the root node(s) of a request or a response always an 
absolute SID value, or could it still be a delta?

In particular:

Sec 2.1 indicates that the translation to/from SID deltas is stateless, 
which implies to me that the root node(s) of a request/response would 
always be an absolute SID value.

Sec 4.2.1 gives an example using a absolute SID for the top node.  It 
then has this text: "

    On the other hand, if the serializer is aware of the parent SID, 1716
    in the case 'system-state' container, root data nodes are encoded
    using deltas.

"

I think that it is quite plausible that the serializer may know the SIDs 
for all nodes in the data tree, which the text implies it could then use 
a relative SID for the top node.  Particularly, if the top level node 
was explicit from the request.

Hence, I think that this draft could probably benefit in being more 
explicit on exactly when a top level node uses an absolute SID, and in 
what scenarios it may end up using a a relative SID. If this distinction 
is down to the protocol being used, then perhaps that could be stated?

One other nit:

Section 4.4.1 says "delta encoding can be performed", but I think that 
this should probably be "delta encoding MUST be performed".

Thanks,
Rob