Re: [netconf] [yang-doctors] Yangdoctors last call review of draft-ietf-netconf-subscribed-notifications-21

Andy Bierman <andy@yumaworks.com> Thu, 24 January 2019 17:29 UTC

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From: Andy Bierman <andy@yumaworks.com>
Date: Thu, 24 Jan 2019 09:29:32 -0800
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To: "Eric Voit (evoit)" <evoit@cisco.com>
Cc: Martin Bjorklund <mbj@tail-f.com>, "Reshad Rahman (rrahman)" <rrahman@cisco.com>, "alexander.clemm@huawei.com" <alexander.clemm@huawei.com>, "yang-doctors@ietf.org" <yang-doctors@ietf.org>, "netconf@ietf.org" <netconf@ietf.org>, "draft-ietf-netconf-subscribed-notifications.all@ietf.org" <draft-ietf-netconf-subscribed-notifications.all@ietf.org>
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Subject: Re: [netconf] [yang-doctors] Yangdoctors last call review of draft-ietf-netconf-subscribed-notifications-21
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On Thu, Jan 24, 2019 at 9:04 AM Eric Voit (evoit) <evoit@cisco.com>; wrote:

> > "Eric Voit (evoit)" <evoit@cisco.com>; wrote:
> > > > From: Martin Bjorklund, January 24, 2019 9:40 AM
> > > >
> > > > "Eric Voit (evoit)" <evoit@cisco.com>; wrote:
> > > > > > From: Martin Bjorklund, January 24, 2019 8:17 AM
> > > > > >
> > > > > > "Eric Voit (evoit)" <evoit@cisco.com>; wrote:
> > > > > > > Hi Andy,
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > Thanks very much for the thorough YANG Doctor review.  I have
> > > > > > > included the
> > > > > > agreed upon comments, and uploaded to:
> > > > > > >
> > > > > > > draft-ietf-netconf-subscribed-notifications-22
> > > > > > >
> > > > > > > a summary of the clarifications made is at the end of the
> document.
> > > > > > > Let me know if there anything else needed to conclude the YANG
> > > > > > > doctor review of this document.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > Also as the result of the ‘error-tag’ discussion with you and
> > > > > > > Martin, we need to perform the refinement of the ‘error-tag’
> > > > > > > mapping within both
> > > > > > > draft-ietf-netconf-netconf-event-notifications
> > > > Section
> > > > > > > 7, and draft-ietf-netconf-restconf-notif Section 3.3.
>  Directly
> > > > > > > below is some text and proposed error-tag mappings for those
> > > > > > > documents.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >     o  An "error-tag" node with the value being a string that
> > > > > > >
> > > > > > >        corresponds to an identity associated with the error.
> > > > > > > This
> > > > > > >
> > > > > > >        "error-tag" will correspond to the error identities
> > > > > > > within
> > > > > > >
> > > > > > >        [I-D.draft-ietf-netconf-subscribed-notifications]
> > > > > > > section
> > > > > > >
> > > > > > >        2.4.6 for general subscription errors:
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >           error identity         uses error-tag
> > > > > > >
> > > > > > >           ---------------------- --------------
> > > > > > >
> > > > > > >           dscp-unavailable       invalid-value
> > > > > >
> > > > > > Ok.  But it is not clear to me when this error is actually
> > > > > > supposed to be generated?  The leaf and identity have the same
> > > > > > if-feature, so it isn't a special errro code for "unsupported
> leaf", which is
> > good!
> > > > > >
> > > > > > Then I have to assume it is supposed to be some kind of runtime
> error?
> > > > >
> > > > > Yes.  A publisher, nor the network to which is connects does not
> > > > > have
> > > > > to:
> > > > > (a) support all DSCP values, nor
> > > > > (b) allow a particular value requested by a particular subscriber,
> > > > > So this condition allows a publisher to reject a request for a
> > > > > DSCP value where is knows the value will not be respected.
> > > >
> > > > Good explanation, I wish it was part of the "leaf dscp" in the
> > > > module
> > > > :)
> > > >
> > > > The dscp-unavailable identity doesn't add any addition value
> > > > compared to the standard error.
> > >
> > > For NETCONF and RESTCONF, this is the case.
> >
> > And comi.  The point is, what makes the rpcs in this module so special
> > that they have to invent a new error reporting scheme?   If we do that
> > for these rpcs, why not for all other rpc in all other modules?
>
> The current RPC error mechanisms ties YANG RPCs to NETCONF and RESTCONF
> transports.   Over many years there has been lots of work to align the
> subscription drafts to these existing mechanisms, while maintaining as much
> transport independence for hints as possible.
>
>

The subscription draft changes error reporting in significant ways, for the
worse, not the better.
There are a set of error-tag values that are used for all protocol
operations defined with rpc-stmt.
It was first defined in NETCONF but it has been applied to RESTCONF as well.

This draft uses identities to replace the set of common error-tags.
Instead, every single
rpc-stmt can have its own set of error codes. Even worse, a different set
of error codes
depending on the protocol that was used.

Why should a 'resource-denied' error be something different in RESTCONF vs.
NETCONF?
Or even in CoMI or some unknown protocol?  Why would 'invalid-value' be
different,
depending on the operation?

It is 1 thing to change the documentation of YANG-based protocol operations.
It is another to omit mandatory information needed to work with NETCONF and
RESTCONF.
If the error-tag values are properly documented and the NETCONF and
RESTCONF mappings are identical
then there should not be any problems using standard error reporting.


Andy



> > > > > Thinking some more, what is supposed to happen if the client on
> > > > > > the same session sends first an establish-subscription with dscp
> > > > > > 42, and then another establish-subscription with dscp 10?
> > > > >
> > > > > This would be allowed.
> > > >
> > > > On linux at least this is a sockopt, i.e., the option applies to the
> > > > socket, which means all packets on the session.  So how is this
> > > > supposed to be implemented if different messages on the session
> > > > should have different dscp values?
> > > > Or is the
> > > > idea that you send the msg, flush all data from ssh/tls to tcp, then
> > > > flush the tcp buffers (not that easy...)?
> > > >
> > > > Even if there's just one establish-subscription with a dscp value,
> > > > since it applies to the session it means that all normal rpcs on
> > > > this session will get the same dscp value.  It is not clear that
> > > > this is the intention?
> > >
> > > For a NETCONF session, I agree that an implementation need not try to
> > > attempt to support more than one DSCP for that session.  And the error
> > > identity dscp-unavailable is a valid response here.
> >
> > Then that should be explained (preferrably in the leaf dscp).
> >
> > > For RESTCONF and other transports, there options which can more
> > > flexibly support different DSCP values.  This is one reason I was
> > > pushing hard in 2016 to leverage HTTP2.
> >
> > We're talking about dynamic subscriptions here.  I don't think anyone has
> > suggested HTTP2 for dynamic subscriptions.
>
> I have always believed that HTTP2 for dynamic subscriptions was a useful
> industry target.   This driver was the original reason I wrote the original
> draft which became draft-ietf-netconf-restconf-notif, and many variations
> on dynamic subscriptions with HTTP2.    In the meantime, GRPC subscriptions
> (based on HTTP2) has grown into this space.
>
> Eric
>
> > For configured subscriptions, this is not an issue, not even for NETCONF.
> >
> >
> > /martin
> >
> >
> >
> > >
> > > Eric
> > >
> > > > /martin
> > > >
> > > >
> > > > > The interesting part comes with bundling the event records.  The
> > > > > initial versions of draft-ietf-netconf-notification-messages
> > > > > required that all event records in a bundle had a common dscp.  At
> > > > > this point, that seems overly restrictive to the marshalling
> > > > > process, so for now that requirement is not in the document.
> > > > >
> > > > > > >           encoding-unsupported   invalid-value
> > > > > >
> > > > > > Ok.  But this identity doesn't give more information than the
> > > > > > standard
> > > > > > error:
> > > > > >
> > > > > >   error-tag: invalid-value
> > > > > >   error-path: /rpc/establish-subscription/encoding
> > > > > >
> > > > > >
> > > > > > >           filter-unavailable     invalid-value
> > > > > >
> > > > > > This is a "subscription-terminated-reason", which will never be
> > > > > > sent in an rpc- error, and thus should not be mapped to an
> error-tag.
> > > > >
> > > > > Yes, forgot to remove those.  It is now out.
> > > > >
> > > > > > >          filter-unsupported     invalid-value
> > > > > >
> > > > > > Ok.  But this identity doesn't give more information than the
> > > > > > standard
> > > > > > error:
> > > > > >
> > > > > >   error-tag: invalid-value
> > > > > >   error-path: /rpc/establish-subscription/stream-xpath-filter
> > > > > >
> > > > > >
> > > > > > >           insufficient-resources resource-denied
> > > > > >
> > > > > >
> > > > > > Ok.  But this identity doens't give more information than the
> > > > > > standard error in the case of establish-subscription and
> > > > > > modify-subscription.
> > > > > >
> > > > > > >           no-such-subscription   invalid-value
> > > > > >
> > > > > > Ok.  But this identity doens't give more information than the
> > > > > > standard error in the case of establish-subscription and
> > > > > > modify-subscription.
> > > > > >
> > > > > > >           replay-unsupported     operation-not-supported
> > > > > >
> > > > > > Ok.  But this identity doesn't give more information than the
> > > > > > standard error.
> > > > > >
> > > > > > >           stream-unavailable     invalid-value
> > > > > >
> > > > > > This is a "subscription-terminated-reason", which will never be
> > > > > > sent in an rpc- error, and thus should not be mapped to an
> error-tag.
> > > > >
> > > > > Yes, forgot to remove those.  It is now out.
> > > > >
> > > > > > >           suspension-timeout     operation-failed
> > > > > >
> > > > > > This is a "subscription-terminated-reason", which will never be
> > > > > > sent in an rpc- error, and thus should not be mapped to an
> error-tag.
> > > > >
> > > > > Yes, forgot to remove those.  It is now out.
> > > > >
> > > > > > >           unsupportable-volume   too-big
> > > > > >
> > > > > > This is a "subscription-terminated-reason", which will never be
> > > > > > sent in an rpc- error, and thus should not be mapped to an
> error-tag.
> > > > >
> > > > > Yes, forgot to remove those.  It is now out.
> > > > >
> > > > > > >        Or this "error-tag" will correspond to the error
> > > > > > > identities
> > > > > > >
> > > > > > >        within [I-D.ietf-netconf-yang-push] Appendix A.1 for
> > > > > > >
> > > > > > >        subscription errors specific to YANG datastores:
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >           error identity              uses error-tag
> > > > > > >
> > > > > > >           ----------------------      --------------
> > > > > > >
> > > > > > >           cant-exclude                operation-not-supported
> > > > > > >
> > > > > > >           datastore-not-subscribable  operation-not-supported
> > > > > >
> > > > > > I think that this should be invalid-value.
> > > > >
> > > > > Ok
> > > > >
> > > > > /Eric
> > > > >
> > > > > > >           no-such-subscription-resync invalid-value
> > > > > >
> > > > > > Ok, but again the value of having this is unclear.
> > > > > >
> > > > > > >           on-change-unsupported       operation-not-supported
> > > > > > >
> > > > > > >           on-change-sync-unsupported  operation-not-supported
> > > > > > >
> > > > > > >           period-unsupported          invalid-value
> > > > > > >
> > > > > > >           update-too-big              too-big
> > > > > > >
> > > > > > >           sync-too-big                too-big
> > > > > > >
> > > > > > >           unchanging-selection        operation-failed
> > > > > >
> > > > > >
> > > > > >
> > > > > > /martin
> > > > > >
> > > > > >
> > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > Do you (or anyone else in this thread) have any suggestions on
> > > > > > > the text or proposed mappings?  If this turns out to be ok,
> > > > > > > Alex will need to remove the NETCONF error-tag specifics from
> > > > > > > draft-ietf-netconf-yang-push Sections 4.4.1 & 4.4.2
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > Also Reshad will have to do some work because he is the YANG
> > > > > > > doctor of
> > > > > > netconf-netconf-event-notifications, and he will want to include
> > > > > > the same information within draft-ietf-netconf-restconf-notif.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > Thanks,
> > > > > > >
> > > > > > > Eric
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > From: Andy Bierman <andy@yumaworks.com>;
> > > > > > >
> > > > > > > Sent: Wednesday, January 23, 2019 12:42 PM
> > > > > > >
> > > > > > > To: Eric Voit (evoit) <evoit@cisco.com>;
> > > > > > >
> > > > > > > Cc: Martin Bjorklund <mbj@tail-f.com>;; yang-doctors@ietf.org;
> > > > > > > netconf@ietf.org;
> > > > > > > draft-ietf-netconf-subscribed-notifications.all@ietf.org
> > > > > > >
> > > > > > > Subject: Re: [yang-doctors] Yangdoctors last call review of
> > > > > > > draft-ietf-netconf-subscribed-notifications-21
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > On Wed, Jan 23, 2019 at 4:35 AM Eric Voit (evoit)
> > > > > > > <mailto:evoit@cisco.com>
> > > > > > wrote:
> > > > > > >
> > > > > > > > From: Martin Bjorklund, January 23, 2019 3:32 AM
> > > > > > >
> > > > > > > >
> > > > > > >
> > > > > > > > Hi,
> > > > > > >
> > > > > > > >
> > > > > > >
> > > > > > > > "Eric Voit (evoit)" <mailto:evoit@cisco.com> wrote:
> > > > > > >
> > > > > > > > > Hi Andy,
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > Looking at your proposal...  My reading is that it takes
> > > > > > > > > the transport
> > > > > > >
> > > > > > > > > specific error info contained in
> > > > > > >
> > > > > > > > > draft-ietf-netconf-netconf-event-notifications section 7,
> > > > > > > > > and then
> > > > > > >
> > > > > > > > > replicates that info within 12 separate description
> > > > > > > > > objects of the
> > > > > > >
> > > > > > > > > transport independent ietf-subscribed-notifications.yang.
> > > > > > > > > The value
> > > > > > >
> > > > > > > > > you are asserting is that RFCs containing YANG models
> > > > > > > > > containing the
> > > > > > >
> > > > > > > > > rpc-stmt have traditionally document the
> > > > > > > > > mandatory-to-implement
> > > > > > >
> > > > > > > > > "error-tag" field within the model.  And presumably you
> > > > > > > > > are concerned
> > > > > > >
> > > > > > > > > that developers should not have to look elsewhere for this
> > > > > > >
> > > > > > > > > information.
> > > > > > >
> > > > > > > >
> > > > > > >
> > > > > > > > I think that maybe there are two separate issues here.
> > > > > > >
> > > > > > > >
> > > > > > >
> > > > > > > > The first issue is that for each error identity defined,
> > > > > > > > there needs to be a
> > > > > > >
> > > > > > > > mapping to the protocol-specific error handling.  Andy
> > > > > > > > suggests that this info is
> > > > > > >
> > > > > > > > added to this document, but currently this information is
> > > > > > > > available in the
> > > > > > >
> > > > > > > > protcol-mapping documents (netconf-notif and restconf-notif).
> > > > > > > > Personally, I
> > > > > > >
> > > > > > > > think that the current split of text between documents is
> fine.
> > > > > > >
> > > > > > > >
> > > > > > >
> > > > > > > > The second issue is that currently, both netconf-notif and
> > > > > > > > restconf-notif say
> > > > > > >
> > > > > > > > that *all* these errors use the error-tag "operation-failed".
> > > > > > > > Essentially it means
> > > > > > >
> > > > > > > > that we bypass the error handling in the protocols.  As Andy
> > > > > > > > points out below,
> > > > > > >
> > > > > > > > the error "insufficient-resources" should be mapped to
> > > > > > > > "resource-denied" in
> > > > > > >
> > > > > > > > NETCONF and RESTCONF (they mean the same thing).  So it
> > > > > > > > might make sense
> > > > > > >
> > > > > > > > to carefully go through the list of errors and map them to
> > > > > > > > the correct error-tag
> > > > > > >
> > > > > > > > (but specifiy this in the transport drafts).
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > I am completely good with this.   Does this work for you Andy?
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > This is better.
> > > > > > >
> > > > > > > I'm glad no other drafts are creating their own error
> > > > > > > reporting system for
> > > > > > each rpc-stmt.
> > > > > > >
> > > > > > > This is a bad precedent and likely to be skipped in
> implementations.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > Eric
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > > /martin
> > > > > > >
> > > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > Andy
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > >
> > > > > > >
> > > > > > > >
> > > > > > >
> > > > > > > >
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > If the YANG doctors require this, it can be inserted.  A
> > > > > > > > > similar text
> > > > > > >
> > > > > > > > > change would be needed for quite a few error identities
> > > > > > > > > within YANG
> > > > > > >
> > > > > > > > > Push.  Personally I don’t like that YANG models should be
> > > > > > > > > required to
> > > > > > >
> > > > > > > > > embed this information.  But I will make the change if you
> > > > > > > > > really want
> > > > > > >
> > > > > > > > > this, and nobody else objects.
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > Other than that, I am not aware of any other open issues
> > > > > > > > > in the YANG
> > > > > > >
> > > > > > > > > Doctor review.  Do you know of anything else?
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > Eric
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > From: Andy Bierman, January 21, 2019 2:26 PM
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > Hi,
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > I think the error-tag issue can be resolved by including 1
> > > > > > > > > extra
> > > > > > >
> > > > > > > > > sentence in each error identity.
> > > > > > >
> > > > > > > > > I know this is NETCONF and RESTCONF centric but those are
> > > > > > > > > the only
> > > > > > > > > 2
> > > > > > >
> > > > > > > > > standard protocols supported for the YANG language right
> now.
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > >        If the 'error-tag' field is used in error
> > > > > > > > > reporting,
> > > > > > >
> > > > > > > > >        then the value '<correct error-tag>' MUST be used.
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > For example:
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > OLD:
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > >   identity insufficient-resources {
> > > > > > >
> > > > > > > > >     base establish-subscription-error;
> > > > > > >
> > > > > > > > >     base modify-subscription-error;
> > > > > > >
> > > > > > > > >     base subscription-suspended-reason;
> > > > > > >
> > > > > > > > >     description
> > > > > > >
> > > > > > > > >       "The publisher has insufficient resources to support
> > > > > > > > > the
> > > > > > >
> > > > > > > > >        requested subscription.  An example might be that
> > > > > > > > > allocated CPU
> > > > > > >
> > > > > > > > >        is too limited to generate the desired set of
> > > > > > > > > notification
> > > > > > >
> > > > > > > > >        messages.";
> > > > > > >
> > > > > > > > >   }
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > NEW:
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > >   identity insufficient-resources {
> > > > > > >
> > > > > > > > >     base establish-subscription-error;
> > > > > > >
> > > > > > > > >     base modify-subscription-error;
> > > > > > >
> > > > > > > > >     base subscription-suspended-reason;
> > > > > > >
> > > > > > > > >     description
> > > > > > >
> > > > > > > > >       "The publisher has insufficient resources to support
> > > > > > > > > the
> > > > > > >
> > > > > > > > >        requested subscription.  An example might be that
> > > > > > > > > allocated CPU
> > > > > > >
> > > > > > > > >        is too limited to generate the desired set of
> > > > > > > > > notification
> > > > > > >
> > > > > > > > >        messages. If the 'error-tag' field is used in error
> > > > > > > > > reporting,
> > > > > > >
> > > > > > > > >        then the value 'resource-denied' MUST be used.";
> > > > > > >
> > > > > > > > >   }
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > Andy
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > On Fri, Jan 18, 2019 at 11:53 AM Eric Voit (evoit)
> > > > > > >
> > > > > > > > > <mailto:evoit@cisco.com<mailto:mailto:evoit@cisco.com>>
> wrote:
> > > > > > >
> > > > > > > > > Hi Andy,
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > Thanks.  I have incorporated items where there was
> agreement.
> > > > > > > > > I have
> > > > > > >
> > > > > > > > > removed the items below where you were ok.
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > Remaining below are the open items, with responses.
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > > >    Should be clear somewhere that
> > > > > > >
> > > > > > > > > > >    suspend is for CPU and other resources, and NACM
> > > > > > > > > > > not considered
> > > > > > >
> > > > > > > > > > >    to be a resource.
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > If NACM is active, it needs to be followed.  The text we
> > > > > > > > > > have for
> > > > > > >
> > > > > > > > > > NACM is in Section 5.4.  Do you see something else
> > > > > > > > > > specific to
> > > > > > >
> > > > > > > > > > subscription suspension needed here?  (Maybe I am not
> > > > > > > > > > getting your
> > > > > > >
> > > > > > > > > > point.)
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > No -- OK to leave NACM as terminate-if-loss-of-rights
> > > > > > > > > > (Is there an
> > > > > > >
> > > > > > > > > > error identity for this event?)
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > The identity which applies here is "stream-unavailable".
> > > > > > > > > This is the
> > > > > > >
> > > > > > > > > same identity which would be used if a subscriber had
> > > > > > > > > never sufficient
> > > > > > >
> > > > > > > > > permissions in the first place.  I don't believe we would
> > > > > > > > > want to
> > > > > > >
> > > > > > > > > return an identity specific to when NACM when permissions
> > > > > > > > > have just
> > > > > > >
> > > > > > > > > been changed.
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > > > I3) sec 2.1 para 6:
> > > > > > >
> > > > > > > > > > >    Event records MUST NOT be delivered to a receiver
> > > > > > > > > > > in a different
> > > > > > >
> > > > > > > > > > >    order than they were placed onto an event stream.
> > > > > > >
> > > > > > > > > > >
> > > > > > >
> > > > > > > > > > >   -- does this apply to subscription-state? Think not,
> > > > > > > > > > > they are not events
> > > > > > >
> > > > > > > > > > >     placed in event stream.
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > Agree that they are not on the event stream.  So they do
> > > > > > > > > > not violate
> > > > > > >
> > > > > > > > > > this requirement.
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > Additionally there is supporting text in "Section 2.7:
> > > > > > > > > > subscription
> > > > > > >
> > > > > > > > > > state notifications", including...
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > " Instead, they are inserted (as defined in this
> > > > > > > > > > section) within the
> > > > > > >
> > > > > > > > > > sequence of notification messages sent to a particular
> > > > > > > > > > receiver."
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > >     Need to allow ended or suspended to be sent
> > > > > > >
> > > > > > > > > > >     head-of-line whenever state changes
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > I am not sure that suspended should always be sent
> head-of-line.
> > > > > > >
> > > > > > > > > > Consider
> > > > > > >
> > > > > > > > > > that implementation might want to let the existing queue
> > > > > > > > > > of filtered
> > > > > > >
> > > > > > > > > > event records be sent if is filter complexity causing
> > > > > > > > > > the CPU issue.
> > > > > > >
> > > > > > > > > > That could be different than if it is a bandwidth issue
> > > > > > > > > > driving the
> > > > > > >
> > > > > > > > > > suspension, and you definitely want the
> 'subscription-suspended'
> > > > > > > > > > to
> > > > > > >
> > > > > > > > > > be placed at the head of line.
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > It is up to the publisher to decide when to stop sending
> > > > > > > > > > events on a
> > > > > > >
> > > > > > > > > > subscription.
> > > > > > >
> > > > > > > > > > Obviously the publisher cannot wait until the
> > > > > > > > > > subscription is idle.
> > > > > > >
> > > > > > > > > > The reason it is getting suspended is it is far from
> > > > > > > > > > idle
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > So also up to the publisher wrt/ what to do with any
> > > > > > > > > > events that
> > > > > > >
> > > > > > > > > > have not been delivered yet on a subscription.  Could
> > > > > > > > > > delete them or
> > > > > > >
> > > > > > > > > > save them for when more bandwidth available (for
> > > > > > > > > > example)
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > Agree fully with this.  Is there text required in the
> draft here?
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > ...
> > > > > > >
> > > > > > > > > > Beyond that it is up to the implementation to decide if
> > > > > > > > > > some
> > > > > > >
> > > > > > > > > > un-transmitted queue of event records should be flushed
> > > > > > > > > > and
> > > > > > >
> > > > > > > > > > reprocessed based on the modification.  I do not expect
> > > > > > > > > > this would
> > > > > > >
> > > > > > > > > > popular, as a replay subscription could accomplish this
> > > > > > > > > > same
> > > > > > >
> > > > > > > > > > functional need.
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > Agreed that an implementation can drop at any time and
> > > > > > > > > > increment the
> > > > > > >
> > > > > > > > > > appropriate counters. It will try to to do this, but no
> > > > > > > > > > requirements
> > > > > > >
> > > > > > > > > > except maybe subscription events like 'replay-completed'
> > > > > > > > > > cannot be
> > > > > > >
> > > > > > > > > > dropped
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > Have put a minor tweak into Section 2.7:
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > [old]  subscription state change notifications cannot be
> > > > > > > > > filtered out
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > [new] subscription state change notifications cannot be
> > > > > > > > > dropped or
> > > > > > >
> > > > > > > > > filtered out
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > ...
> > > > > > >
> > > > > > > > > > Thinking more on your point, it might be worth tweaking
> > > > > > > > > > a couple
> > > > > > >
> > > > > > > > > > words to allow for head-of-line placement of
> > > > > > >
> > > > > > > > > > "subscription-suspended".
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > >    "Subscribed event records queued for sending after
> > > > > > > > > > the issuance of
> > > > > > >
> > > > > > > > > >    this
> > > > > > >
> > > > > > > > > >    subscription state change notification may now be
> sent."
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > Are you good with this suggested change?
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > Not sure -- it needs to be clear that
> > > > > > > > > > subscription-suspended is the
> > > > > > >
> > > > > > > > > > last event sent before suspending and
> > > > > > > > > > subscription-resumed is the
> > > > > > >
> > > > > > > > > > first event sent after transition from suspended to
> active.
> > > > > > >
> > > > > > > > > > The next event could also be subscription-terminated.
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > I do think this possibility is covered in the text.  For
> > > > > > > > > Section
> > > > > > > > > 2.7.4
> > > > > > >
> > > > > > > > > subscription-suspended the current text is:
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > "No further notification will be sent until the
> > > > > > > > > subscription resumes
> > > > > > >
> > > > > > > > > or is terminated."
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > And Section 2.7.5 subscription-resumed says":
> > > > > > >
> > > > > > > > > "Subscribed event records generated after the issuance of
> > > > > > > > > this
> > > > > > >
> > > > > > > > > subscription state change notification may now be sent."
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > Based on the discussion, I can make it:
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > "Subscribed event records are again permitted to be sent
> > > > > > > > > following
> > > > > > >
> > > > > > > > > this subscription state change notification."
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > Is this sufficient for you?
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > ...
> > > > > > >
> > > > > > > > > > > I4) sec 2.4.6: RPC Failures
> > > > > > >
> > > > > > > > > > >   -- concern about a subscription-specific error
> > > > > > > > > > > reporting system
> > > > > > >
> > > > > > > > > > >      must make sure protocol error reporting system is
> > > > > > > > > > > used
> > > > > > >
> > > > > > > > > > > correctly
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > Yes.  We have done our best to integrate with the
> > > > > > > > > > embedded NETCONF
> > > > > > >
> > > > > > > > > > and RESTCONF mechanisms.  There is much additional
> > > > > > > > > > information in
> > > > > > >
> > > > > > > > > > the transport drafts here.
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > >   -- The error-tag value needs to be identified for
> each
> > > > > > > > > > >   -- 'reason'
> > > > > > >
> > > > > > > > > > > identity
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > This is done in the transport drafts.  E.g., see
> > > > > > >
> > > > > > > > > > draft-ietf-netconf-netconf-event-
> > > > > > >
> > > > > > > > > > notifications Section 7
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > I do not agree this is a good idea.
> > > > > > >
> > > > > > > > > > Each error identity should simply state the required
> "error-tag"
> > > > > > >
> > > > > > > > > > that is associated with the error.  This is expected of
> > > > > > > > > > protocol
> > > > > > >
> > > > > > > > > > operations that are added to NETCONF and RESTCONF.
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > In draft-ietf-netconf-netconf-event-notifications, section
> > > > > > > > > 7, the
> > > > > > >
> > > > > > > > > required "error-tag" is identified as "operation-failed".
> > > > > > > > > If we
> > > > > > >
> > > > > > > > > instead placed that "error-tag" information in the YANG
> > > > > > > > > model, then we
> > > > > > >
> > > > > > > > > have tied the YANG model to the RESTCONF and NETCONF
> > transports.
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > > Both NETCONF and RESTCONF use a compatible error
> > > > > > > > > > reporting data
> > > > > > >
> > > > > > > > > > structure.
> > > > > > >
> > > > > > > > > > The "error-tag" is used in both of them.  IMO client
> > > > > > > > > > developers do
> > > > > > >
> > > > > > > > > > not want a different set of error codes for the same
> > > > > > > > > > error conditions.
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > draft-ietf-netconf-restconf-notif Section 3.3 also
> > > > > > > > > requires an
> > > > > > >
> > > > > > > > > "error-tag" node of "operation-failed".  So we used the
> > > > > > > > > transport
> > > > > > >
> > > > > > > > > drafts rather than the YANG model to support the same
> > > > > > > > > error codes for
> > > > > > >
> > > > > > > > > the same error conditions.
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > > I agree that transport drafts could define their own
> > > > > > > > > > error
> > > > > > >
> > > > > > > > > > identities, which would document the expected error-tag
> there.
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > >    2.  "modify-subscription-stream-error-info": This
> > > > > > > > > > > MUST be returned
> > > > > > >
> > > > > > > > > > >        with the leaf "reason" populated if an RPC
> > > > > > > > > > > error reason has not
> > > > > > >
> > > > > > > > > > >        been placed elsewhere within the transport
> > > > > > > > > > > portion of a failed
> > > > > > >
> > > > > > > > > > >        "modify-subscription" RPC response.  This MUST
> > > > > > > > > > > be sent if
> > > > > > >
> > > > > > > > > > > hints
> > > > > > >
> > > > > > > > > > >
> > > > > > >
> > > > > > > > > > >   -- all 3 paragraphs like this; unclear what "placed
> > > > > > > > > > >   -- elsewhere"
> > > > > > >
> > > > > > > > > > >       text means; not appropriate for MUST;
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > Instead of "placed elsewhere", how about: "placed in
> > > > > > > > > > subscription
> > > > > > >
> > > > > > > > > > transport document defined object".  Would this be
> sufficient?
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > No -- NETCONF and RESTCONF have well-defined error
> reporting.
> > > > > > >
> > > > > > > > > > The server requirements for this error reporting must be
> > > > documented.
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > I agree with the following approach:
> > > > > > >
> > > > > > > > > >   - each operation MUST identify the error-tags that are
> > > > > > > > > > expected for
> > > > > > >
> > > > > > > > > >     various error conditions (such s is done in RFC
> > > > > > > > > > 6241)
> > > > > > >
> > > > > > > > > >   - the server MUST return the specified error-tags. If
> > > > > > > > > > a condition not
> > > > > > >
> > > > > > > > > >   - explicitly
> > > > > > >
> > > > > > > > > >     defined then the server MUST pick the appropriate
> > > > > > > > > > error-tag from RFC
> > > > > > >
> > > > > > > > > >     6241
> > > > > > >
> > > > > > > > > >  - the server MAY include the specified rc:yang-data in
> > > > > > > > > > the
> > > > > > >
> > > > > > > > > > <error-info>
> > > > > > >
> > > > > > > > > >  - data
> > > > > > >
> > > > > > > > > > structure
> > > > > > >
> > > > > > > > > >  - the server MUST use the appropriate rc:yang-data to
> > > > > > > > > > report hints
> > > > > > >
> > > > > > > > > >  - for protocols other than NETCONF and RESTCONF, they
> > > > > > > > > > can map
> > > > > > >
> > > > > > > > > > error-tag
> > > > > > >
> > > > > > > > > >  - or
> > > > > > >
> > > > > > > > > > ignore it,
> > > > > > >
> > > > > > > > > >    but the document defining the protocol operation MUST
> > > > > > > > > > provide
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > Functionally, everything you ask for is fully covered when
> > > > > > > > > you include
> > > > > > >
> > > > > > > > > consider draft-ietf-netconf-netconf-event-notifications
> > > > > > > > > (section
> > > > > > > > > 7)
> > > > > > >
> > > > > > > > > and draft-ietf-netconf-restconf-notif (section 3.3).
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > My read of the issue is that you believe "error-tag" must
> > > > > > > > > be specified
> > > > > > >
> > > > > > > > > in the YANG model.  I believe that "error-tag" shouldn't
> > > > > > > > > be in the
> > > > > > >
> > > > > > > > > YANG model because that would tie the model to a transport
> type.
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > Any thoughts on how we might close this?  If absolutely
> > > > > > > > > required I
> > > > > > >
> > > > > > > > > could place a new comment line in the YANG model under
> > > > > > >
> > > > > > > > > /* Identities for RPC and Notification errors */
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > The comment would be something like:
> > > > > > >
> > > > > > > > > /* When used with NETCONF and RESTCONF RPCs:
> > > > > > >
> > > > > > > > >     "error-type" node to be used is "application"
> > > > > > >
> > > > > > > > >      "error-tag" must be "operation-failed".  */
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > This seems incongruous.  Just throwing it out as a
> suggestion.
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > > In any case, the -v21 wording results from the attempted
> > > > > > > > > > balancing
> > > > > > >
> > > > > > > > > > the WG requests for:
> > > > > > >
> > > > > > > > > > * merging with transport protocol error mechanisms
> > > > > > >
> > > > > > > > > > * WG leadership guidance to provide requirements for
> > > > > > > > > > transport
> > > > > > >
> > > > > > > > > > documents
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > >      Only 3 fields seem
> > > > > > >
> > > > > > > > > > >       to be relevant (error-tag, error-app-tag,
> error-info).
> > > > > > >
> > > > > > > > > > >       Protcol operations are expected to document
> > > > > > > > > > > server requirements
> > > > > > >
> > > > > > > > > > >       for these 3 fields, if applicable.  Only the
> > > > > > > > > > > error-tag
> > > > > > >
> > > > > > > > > > >       is mandatory-to-use.
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > Hopefully these are covered sufficiently when this
> > > > > > > > > > document is
> > > > > > >
> > > > > > > > > > coupled with the NETCONF and RESTCONF Notif transport
> > > > documents.
> > > > > > >
> > > > > > > > > > For other transports, the tags you identify about would
> > > > > > > > > > not be
> > > > > > >
> > > > > > > > > > applicable.
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > >   -- the error assignments are extremely specific.
> > > > > > > > > > > e.g., it is not
> > > > > > >
> > > > > > > > > > >      possible for <kill-subscription> to fail with an
> > > > > > >
> > > > > > > > > > >      'insufficient-resources' error;
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > This is the intent of the base specification, e.g., we
> > > > > > > > > > don't believe
> > > > > > >
> > > > > > > > > > a
> > > > > > >
> > > > > > > > > > kill-
> > > > > > >
> > > > > > > > > > subscription should fail for an insufficient-resources
> reason.
> > > > > > > > > > But
> > > > > > >
> > > > > > > > > > vendors might desire more specificity.  As a result is
> > > > > > > > > > certainly ok
> > > > > > >
> > > > > > > > > > for vendor implementations to add new error identities.
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > IMO anything can fail for insufficient resources. That
> > > > > > > > > > is very
> > > > > > >
> > > > > > > > > > implementation-
> > > > > > >
> > > > > > > > > > specific.
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > Instead of implementation specific I would call it
> > > > > > > > > application
> > > > > > >
> > > > > > > > > specific.  Right now we don't have a catch-all
> > > > > > > > > error-identity of
> > > > > > >
> > > > > > > > > 'other-error'.  We preferred that error conditions beyond
> > > > > > > > > the current
> > > > > > >
> > > > > > > > > ones listed could be included by vendors as needed.
> > > > > > > > > Further
> > > > > > >
> > > > > > > > > deployment experience could result in new error identities
> > > > > > > > > surfacing
> > > > > > >
> > > > > > > > > for standardization should this draft catch on.
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > > >      Do not agree that scoping each
> > > > > > >
> > > > > > > > > > >      identity to specific RPC operations is a good
> idea.
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > This level of specificity was not the author's original
> plans.
> > > > > > > > > > Nor
> > > > > > >
> > > > > > > > > > was this level of specificity part of earlier draft
> > > > > > > > > > versions up
> > > > > > >
> > > > > > > > > > through -v08.  However members of the WG made it clear
> > > > > > > > > > that such
> > > > > > >
> > > > > > > > > > specificity was necessary for draft progression.
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > >   -- how are errors in these parameters reported for
> > > > > > > > > > > configured
> > > > > > >
> > > > > > > > > > >      subscriptions when <edit-config> is the RPC that
> has the
> > > > > > > > > > >      error?
> > > > > > >
> > > > > > > > > > >      How are the yang-data structs used for
> > > > > > > > > > > edit-config or commit
> > > > > > errors?
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > None of these yang-data structures are specified for use
> > > > > > > > > > with
> > > > > > >
> > > > > > > > > > <edit-config> operations.  For <edit-config>, the change
> > > > > > > > > > to a
> > > > > > >
> > > > > > > > > > configured subscription would be written to the
> > > > > > > > > > datastore if it were
> > > > > > >
> > > > > > > > > > semantically valid.  At this point the subscription
> > > > > > > > > > enters the
> > > > > > >
> > > > > > > > > > [evaluate] points of Figure 8.  Issues from this point
> > > > > > > > > > out would be
> > > > > > >
> > > > > > > > > > reported with a vendor specific construct such as SYSLOG.
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > So how are hints reported for configured subscriptions?
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > There is nothing in the specification which requires this.
> > > > > > > > > An
> > > > > > >
> > > > > > > > > implementation could choose to place these in some form of
> > SYSLOG.
> > > > > > >
> > > > > > > > > ...
> > > > > > >
> > > > > > > > > > > I6) sec 2.5, para 3:
> > > > > > >
> > > > > > > > > > >
> > > > > > >
> > > > > > > > > > >    On a receiver of a
> > > > > > >
> > > > > > > > > > >    configured subscription, support for dynamic
> > > > > > > > > > > subscriptions is
> > > > > > >
> > > > > > > > > > >    optional except where replaying missed event
> records is
> > > > > > > > > > >    required.
> > > > > > >
> > > > > > > > > > >
> > > > > > >
> > > > > > > > > > >   -- confusing because text in 1.3:
> > > > > > >
> > > > > > > > > > >      Note that there is no mixing-and-matching of
> > > > > > > > > > > dynamic and configured
> > > > > > >
> > > > > > > > > > >      operations on a single subscription.
> > > > > > > > > > > Specifically, a configured
> > > > > > >
> > > > > > > > > > >   -- clarify the receiver may have multiple
> > > > > > > > > > > subscriptions here
> > > > > > >
> > > > > > > > > > >   -- not clear what "except where replaying..." text
> > > > > > > > > > > means
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > How about the following tweak:
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > "On a receiver of a configured subscription, support for
> > > > > > > > > > dynamic
> > > > > > >
> > > > > > > > > > subscriptions is optional.  However if replaying missed
> > > > > > > > > > event
> > > > > > >
> > > > > > > > > > records is required for a configured subscription,
> > > > > > > > > > support for
> > > > > > >
> > > > > > > > > > dynamic subscription is highly recommended.  In this
> > > > > > > > > > case, a
> > > > > > >
> > > > > > > > > > separate dynamic subscription can be established to
> > > > > > > > > > retransmit the
> > > > > > >
> > > > > > > > > > missing event records."
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > OK
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > Change made.
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > > > I7) leaf stream-xpath-filter: [multiple uses]
> > > > > > >
> > > > > > > > > > >
> > > > > > >
> > > > > > > > > > >            The expression is evaluated in the
> following XPath
> > > > > > > > > > >            context:
> > > > > > >
> > > > > > > > > > >
> > > > > > >
> > > > > > > > > > >              o The set of namespace declarations is
> the set of
> > > > > > > > > > >              prefix
> > > > > > >
> > > > > > > > > > >                  and namespace pairs for all YANG
> > > > > > > > > > > modules implemented
> > > > > > >
> > > > > > > > > > >                  by the server, where the prefix is
> > > > > > > > > > > the YANG module
> > > > > > >
> > > > > > > > > > >                  name and the namespace is as defined
> > > > > > > > > > > by the
> > > > > > >
> > > > > > > > > > >                  'namespace' statement in the YANG
> module.
> > > > > > >
> > > > > > > > > > >
> > > > > > >
> > > > > > > > > > >   -- This prefix processing is not done anywhere else
> > > > > > > > > > > in NETCONF
> > > > > > >
> > > > > > > > > > >      or RESTCONF.  IMO a bad precedent.  Only the XML
> > > > > > > > > > > prefixes
> > > > > > >
> > > > > > > > > > >      should be required for processing of XML encoding.
> > > > > > > > > > > YANG
> > > > > > >
> > > > > > > > > > >      module prefixes are not required to be unique,
> > > > > > > > > > > unlike
> > > > > > >
> > > > > > > > > > >      the prefix mappings in XML
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > This text was proposed by Martin as a result of the
> > > > > > > > > > "xpath
> > > > > > >
> > > > > > > > > > expressions in JSON"
> > > > > > >
> > > > > > > > > > thread last October in NETMOD.
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > I am happy to incorporate whatever text is appropriate.
> > > > > > > > > > I was
> > > > > > >
> > > > > > > > > > hoping that the suggested text was sufficient for now.
> > > > > > > > > > Kent has
> > > > > > >
> > > > > > > > > > already incorporated this as an issue for yang-next
> > > > > > >
> > > > > > > > > > https://github.com/netmod-wg/yang-next/issues/55
> > > > > > >
> > > > > > > > > > So hopefully there is no final precedent being claimed.
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > I do not agree that this YANG module should define a new
> > > > > > > > > > way to
> > > > > > >
> > > > > > > > > > encode XPath into XML instance documents. This will
> > > > > > > > > > require
> > > > > > >
> > > > > > > > > > significant changes to server implementations.  YANG
> > > > > > > > > > module prefixes
> > > > > > >
> > > > > > > > > > are not even required to be unique so the set of
> > > > > > > > > > prefixes used by
> > > > > > >
> > > > > > > > > > the server in XML instance documents may be different,
> > > > > > > > > > since it must
> > > > > > >
> > > > > > > > > > be unique.
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > See next note
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > > >   -- NMDA allows the same module to appear in multiple
> > > > > > > > > > > module-sets
> > > > > > >
> > > > > > > > > > >      and different in each datastore. This text about
> > > > > > > > > > > "implemented by
> > > > > > >
> > > > > > > > > > >      the server" does not work for NMDA
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > I am happy to adopt whatever text meets YANG doctor
> approval.
> > > > > > > > > > Can
> > > > > > >
> > > > > > > > > > you suggest?
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > Remove all text about YANG prefixes and continue using
> > > > > > > > > > XML encoding
> > > > > > >
> > > > > > > > > > without modification
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > As a different YANG doctor has required the current text
> > > > > > > > > modification,
> > > > > > >
> > > > > > > > > I believe this is a blocker.  What is the process for YANG
> > > > > > > > > model
> > > > > > >
> > > > > > > > > reviews in such a case.  I am happy to accept whatever
> here.
> > > > > > > > > Any
> > > > > > >
> > > > > > > > > suggestions on next steps?
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > ...
> > > > > > >
> > > > > > > > > > >   -- there should be an example of a configurable
> > > > > > > > > > > encoding
> > > > > > >
> > > > > > > > > > > provided
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > I am happy to enhance the definition YANG model's
> > > > > > > > > > identity
> > > > > > >
> > > > > > > > > > definition of "configurable-encoding".  I could do this
> > > > > > > > > > by adding
> > > > > > >
> > > > > > > > > > the following additional text to the description: "An
> > > > > > > > > > example of a
> > > > > > >
> > > > > > > > > > configurable encoding might be a new identity such as
> > > > > > > > > > 'encode-cbor'.
> > > > > > >
> > > > > > > > > > Such an identity could use
> > > > > > >
> > > > > > > > > > 'configurable-
> > > > > > >
> > > > > > > > > > encoding' as its base.  This would allow a dynamic
> > > > > > > > > > subscription
> > > > > > >
> > > > > > > > > > encoded in JSON [RFC-8259] to request notification
> > > > > > > > > > messages be
> > > > > > >
> > > > > > > > > > encoded via CBOR [RFC- 7049].  Further details for any
> > > > > > > > > > specific
> > > > > > >
> > > > > > > > > > configurable encoding would be explored in a transport
> > > > > > > > > > document
> > > > > > >
> > > > > > > > > > based on this specification."  Does this meet your ask?
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > OK
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > Added
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > > > I11) extension subscription-state-notification {
> > > > > > >
> > > > > > > > > > >
> > > > > > >
> > > > > > > > > > >        This statement is not for use
> > > > > > >
> > > > > > > > > > >        outside of this YANG module.";
> > > > > > >
> > > > > > > > > > >
> > > > > > >
> > > > > > > > > > >   -- this text should be removed. There is no value in
> > > > > > > > > > > limiting
> > > > > > >
> > > > > > > > > > >      the scope of this extension.  It prevents even
> > > > > > > > > > > this WG from
> > > > > > >
> > > > > > > > > > >      creating a module that uses the extension again.
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > This was the subject of significant debate in the WG.
> > > > > > > > > > The authors
> > > > > > >
> > > > > > > > > > did not want this restriction either.
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > To be allowed to progress the document, we inserted the
> > > > > > > > > > document.
> > > > > > >
> > > > > > > > > > If this really is mandatory-to-remove from a YANG doctor
> > > > > > >
> > > > > > > > > > point-of-view, what is the process for quick closure on
> > > > > > > > > > this issue
> > > > > > >
> > > > > > > > > > between WG leadership and the YANG doctors?
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > The YANG language makes no restrictions about exporting
> > > > statements.
> > > > > > >
> > > > > > > > > > I guess I missed that debate so I will just say OK and
> > > > > > > > > > wonder what
> > > > > > >
> > > > > > > > > > problem this is supposed to solve. I guess the WG wants
> > > > > > > > > > to give YANG
> > > > > > >
> > > > > > > > > > Doctors more things to check. (This is what we called a
> > > > > > > > > > CLR in
> > > > > > >
> > > > > > > > > > SNMP-land ;-)
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > Thanks.  No action taken.
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > > > I13)   notification subscription-started {
> > > > > > >
> > > > > > > > > > >     sn:subscription-state-notification;
> > > > > > >
> > > > > > > > > > >     if-feature "configured";
> > > > > > >
> > > > > > > > > > >     description
> > > > > > >
> > > > > > > > > > >       "This notification indicates that a subscription
> > > > > > > > > > > has started and
> > > > > > >
> > > > > > > > > > >         notifications are beginning to be sent. This
> > > > > > > > > > > notification shall
> > > > > > >
> > > > > > > > > > >        only be sent to receivers of a subscription; it
> > > > > > > > > > > does not
> > > > > > >
> > > > > > > > > > >        constitute a general-purpose notification.";
> > > > > > >
> > > > > > > > > > >
> > > > > > >
> > > > > > > > > > >   -- 2nd sentence is confusing; all notifications are
> > > > > > > > > > > sent to
> > > > > > >
> > > > > > > > > > >      receivers of a subscription. last part is
> > > > > > > > > > > redundant since
> > > > > > >
> > > > > > > > > > >      the sn:subscription-state-notification extension
> > > > > > > > > > > is used
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > There is no issue with removing this second sentence
> completely.
> > > > > > > > > > If
> > > > > > >
> > > > > > > > > > I did that, would this address your concern?
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > OK
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > Done
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > > > I14)   rc:yang-data
> modify-subscription-stream-error-info {
> > > > > > >
> > > > > > > > > > >
> > > > > > >
> > > > > > > > > > >       leaf filter-failure-hint {
> > > > > > >
> > > > > > > > > > >         type string;
> > > > > > >
> > > > > > > > > > >           description
> > > > > > >
> > > > > > > > > > >             "Information describing where and/or why a
> > > > > > > > > > > provided filter
> > > > > > >
> > > > > > > > > > >              was unsupportable for a subscription.";
> > > > > > >
> > > > > > > > > > >       }
> > > > > > >
> > > > > > > > > > >
> > > > > > >
> > > > > > > > > > >   -- rpc-error already allows more precise error
> > > > > > > > > > > reporting
> > > > > > >
> > > > > > > > > > >      It uses error-tag, error-path, error-string, and
> > > > > > > > > > > error-info
> > > > > > >
> > > > > > > > > > >      extensions
> > > > > > >
> > > > > > > > > > >      to identify which parameters/conditions caused
> > > > > > > > > > > the RPC to be
> > > > > > >
> > > > > > > > > > >      rejected.
> > > > > > >
> > > > > > > > > > >      This error reporting will continue to be used,
> > > > > > > > > > > Not sure this
> > > > > > >
> > > > > > > > > > >      failure-hint
> > > > > > >
> > > > > > > > > > >      has any standards value. Perhaps real-use example
> > > > > > > > > > > can be
> > > > > > >
> > > > > > > > > > > added
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > Per your thoughts on rpc-error...  For NETCONF and
> > > > > > > > > > RESTCONF, you
> > > > > > >
> > > > > > > > > > point to error structures which historically been used
> > > > > > > > > > with those
> > > > > > >
> > > > > > > > > > transports.
> > > > > > >
> > > > > > > > > > Of course
> > > > > > >
> > > > > > > > > > we were looking to have all subscription hints
> > > > > > > > > > supportable across
> > > > > > >
> > > > > > > > > > transports via a single portable YANG data structure.
> > > > > > > > > > So the value
> > > > > > >
> > > > > > > > > > is that a single string object exists so to transport
> > > > > > > > > > whatever the
> > > > > > >
> > > > > > > > > > vendor thinks would be useful as a hint in this case.
> > > > > > > > > > I.e., there
> > > > > > >
> > > > > > > > > > has been no attempt to standardize the contents of this
> string.
> > > > > > > > > > If
> > > > > > >
> > > > > > > > > > operational experiences drive a desire for such
> > > > > > > > > > structuring, this
> > > > > > >
> > > > > > > > > > could provide the basis for a new draft building off of
> > > > > > > > > > this
> > > > > > >
> > > > > > > > > > starting point.
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > I guess I do not consider NETCONF and RESTCONF
> > > > > > > > > > "historic" quite
> > > > yet.
> > > > > > >
> > > > > > > > > > There are many implementations using the rpc-error
> > > > > > > > > > reporting with no
> > > > > > >
> > > > > > > > > > intent to replace it with something else.
> > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > > > > > > > I was just asking for an example, since I have no idea
> > > > > > > > > > what an
> > > > > > >
> > > > > > > > > > implementor would put in this leaf.
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > Here is an example from our implementation.  Say you
> > > > > > > > > mistype an extra
> > > > > > >
> > > > > > > > > "\" to an xpath filter:
> > > > > > >
> > > > > > > > > /if:interfaces-state/interface[name="GigabitEthernet0/0"]/
> > > > > > > > > oper
> > > > > > > > > -sta
> > > > > > > > > tus
> > > > > > >
> > > > > > > > > As a result, the filter is passed to the publisher is:
> > > > > > >
> > > > > > > > > /if:inte\rfaces-state/interface[name="GigabitEthernet0/0"]
> > > > > > > > > /ope
> > > > > > > > > r-st
> > > > > > > > > atus
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > What we would return in the failure-hint string is:
> > > > > > >
> > > > > > > > > Invalid expression: offset(9) in
> > > > > > >
> > > > > > > > > '/if:inte\rfaces-state/interface[name="GigabitEthernet0/0"
> > > > > > > > > ]/oper-
> > > > status'
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > Eric
> > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > > > > > Andy
>