Re: [netconf] RFC 6241 Ambiguity

On Wed, May 15, 2019 at 2:48 PM Kent Watsen <kent@watsen.net> wrote:

>
>
> I don't think Erratum 5397 should be deleted. Though the original section
> 7.8 makes no mention of confirmed commits, section 7.9 does, but does not
> differentiate between a vanilla confirmed commit and a persistent confirmed
> commit. Since a persistent confirmed commit is still a type of confirmed
> commit, without clarification the second paragraph of the description would
> seem to apply.
>
>
> I would agree.
>
>
>
7.8 does not say anything about the <kill-session> is for the
session that started a confirmed commit or extended a confirmed commmit.
It could be interpreted to mean any kill-session for any session causes
a confirmed commit to be rolled back.  The text below is so ambiguous it
is not even clear the <kill-session> has to be for an existing session,

      If a NETCONF server receives a <kill-session> request while
      processing a confirmed commit (Section 8.4), it MUST restore the
      configuration to its state before the confirmed commit was issued.

> It's a minor point, but I could argue, as I wrote before, that such
> clarifications in 7.x are unnecessary because 8.4 provides overrides.   I
> prefer less text because it's easier to get right (wit this is at least the
> 3rd time Jonathan is at this now).  However "unnecessary" doesn't mean
> "wrong" and since we've already stepped in it, getting the 7.x errata right
> might be easier than getting 8.4 right.
>
>

8.4 para 3 says the confirmed commit is not tied to a session if the
persist/persist0id mechanism is used.

   If the <persist> element is not given in the confirmed commit
   operation, any follow-up commit and the confirming commit MUST be
   issued on the same session that issued the confirmed commit.  If the
   <persist> element is given in the confirmed <commit> operation, a
   follow-up commit and the confirming commit can be given on any
   session, and they MUST include a <persist-id> element with a value
   equal to the given value of the <persist> element.

The problematic text is actually in <cancel_commit>

8.4.4.1.  <cancel-commit>

   Description:

         Cancels an ongoing confirmed commit.  If the <persist-id>
         parameter is not given, the <cancel-commit> operation MUST be
         issued on the same session that issued the confirmed commit.

In order to cancel a confirmed commit (belonging to another client, i.e
the persist-id is not known), the client issues a <kill-session> for
any random or non-existent session.  It would make more sense to issue a
<cancel-commit>
(maybe require superuser) instead. The access control policy for
<kill-session>
is the wrong way to configure access to cancelling a confirmed commit.

IMO these procedures are not well designed or documented, and an Errata
cannot
be used to fix it -- a new version of the protocol should fix it, in which
WG and IETF consensus
is reached for the selected solution.

> With the diff, should that be against the original text or the original
> erratum?
>
>
> The diff is building on top of the original erratum. I would think a diff
> w.r.t. to the original erratum would make sense.
>
>
> It depends, are you correcting the earlier errata or filing a new one?
> Regardless, I expressed a diff for what I think the text should be (which
> you didn't comment on); how that is translated is up to you.
>
>
> Kent // contributor
>
>
Andy

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