[core] Roman Danyliw's No Objection on draft-ietf-core-new-block-11: (with COMMENT)

Roman Danyliw via Datatracker <noreply@ietf.org> Wed, 05 May 2021 19:17 UTC

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Subject: [core] Roman Danyliw's No Objection on draft-ietf-core-new-block-11: (with COMMENT)
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Roman Danyliw has entered the following ballot position for
draft-ietf-core-new-block-11: No Objection

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----------------------------------------------------------------------
COMMENT:
----------------------------------------------------------------------

** Section 3.2 and Section 11
(a) Section 3.2. It is not recommended that these options are used in a NoSec
security mode

(b) Section 11. It is NOT RECOMMENDED that the NoSec security mode is
   used if the Q-Block1 and Q-Block2 Options are to be used.

I believe that the intend of (a) and (b) is to caution against using NoSec mode
with either Q-Block1 or 2.  One read of (b) would be that this guidance is only
about when both options are used together (e.g., the language of Section 4.7). 
I recommend restating (b) to be more along the lines of:

Therefore, it is NOT RECOMMENDED to use the NoSec security mode if either the
Q-Block1 or Q-Block2 Options is used.

** Section 4.1.  Colloquialism. s/local configuration knob/local configuration
option/

** Section 4.4.

(a)   If the server detects part way through a body transfer that the
   resource data has changed and the server is not maintaining a cached
   copy of the old data, then the transmission is terminated.  Any
   subsequent missing block requests MUST be responded to using the
   latest ETag and Size2 Option values with the updated data.

...

(b) If the server transmits a new body of data (e.g., a triggered Observe
   notification) with a new ETag to the same client as an additional
   response, the client should remove any partially received body held
   for a previous ETag for that resource as it is unlikely the missing
   blocks can be retrieved.

(1) Is (a) suggesting that the missing block requests would be serviced from a
copy of the “resource data that has changed”?  This would mean that the client
would get an inconsistent version of the resource which is neither the old or
new version.

(2) (b) seems like it is noting that the partially received body should in fact
be discarded to avoid the situation in (1).  However, how does the client get
the initial, now discarded blocks?  I’m not sure where that transmission
shouldn’t fail with an error as I don’t follow how recover is possible.