Re: [Netconf] IETF 101 SN Question 1: Proper designation of receiver (was RE: mbj's WGLC comments on subscribed-notifications-10)

[Kent Watsen <[e-mail]>]

Sorry, just looking at this now while listening to the minutes.  I think we should look at [1] for inspiration.  This is the pattern that the various client/server and syslog documents used.  For instance, notice in [2]:

  module: ietf-netconf-server
      +--rw netconf-server
         +--rw listen {listen}?
            ...
         +--rw call-home {call-home}?
            +--rw netconf-client* [name]
               +--rw name                  string
               +--rw endpoints
                  +--rw endpoint* [name]
                     +--rw name    string
                     +--rw (transport)
                        +--:(ssh) {ssh-call-home}?
                        |  +--rw ssh
                        |     ...
                        +--:(tls) {tls-call-home}?
                           +--rw tls
                              ...

See how there is a 'choice' with a case for each transport?  "Endpoint" here is like your "receiver"... 

[1] https://tools.ietf.org/id/draft-schoenw-netmod-yang-pattern-00.txt
[2] https://tools.ietf.org/html/draft-ietf-netconf-netconf-client-server-05#section-4.1

Kent // contributor



> From: Eric Voit, April 3, 2018 8:25 PM
> 
> At IETF 101, during the subscribed-notifications review, everyone in the
> room seemed good with having a string which acted as the key for a list of
> configured receivers:
> https://urldefense.proofpoint.com/v2/url?u=https-3A__youtu.be_KJtg-2DJ-2D6CZM-3Ft-3D27m39s&d=DwICAg&c=HAkYuh63rsuhr6Scbfh0UjBXeMK-ndb3voDTXcWzoCI&r=9zkP0xnJUvZGJ9EPoOH7Yhqn2gsBYaGTvjISlaJdcZo&m=nPdmcQiJgwYaRYnXOWJQJmL0npaAmtTIQk4YNutZA1I&s=XlKKQ9yScaldHxhsVmnkW8vDLpmTgU_4u2wD_WC6BDQ&e=
> What was unresolved was that we still needed to choose the preferred way
> to enforce each receiver initiating a call-home using the configured
> subscription's transport.
> 
> Further below in the thread, Martin proposes a structure to accomplish
> this.  Please note however that a natural outcome of Martin's suggestion is
> the placing of a small YANG model within draft-ietf-netconf-netconf-event-
> notifications which just defines an identity for "NETCONF".  Specifically:
> 
>   identity netconf {
>     base sn:transport;
>     base sn:inline-address;
>     description
>       "NETCONF is used as a transport for notification messages and
>        state change notifications.";
>   }
> 
> (  For the full min-model with all the boilerplate, see:
> https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_netconf-2Dwg_notif-2Dnetconf_blob_master_draft-2Dietf-2D&d=DwICAg&c=HAkYuh63rsuhr6Scbfh0UjBXeMK-ndb3voDTXcWzoCI&r=9zkP0xnJUvZGJ9EPoOH7Yhqn2gsBYaGTvjISlaJdcZo&m=nPdmcQiJgwYaRYnXOWJQJmL0npaAmtTIQk4YNutZA1I&s=ADVNhk_g5Zew9bG9F48_mtfHGr46qSglpAL4AKzJFNY&e=
> netconf-netconf-event-notifications-10.txt   )
> 
> The benefit of having this very short model in draft-ietf-netconf-netconf-
> event-notifications is that it is quite easy to enforce the proper call home
> mechanism for NETCONF based receivers.   Another benefit is that we also
> can create additional mini models for the RESTCONF / HTTP draft and for
> other transports as they are built out.
> 
> Does anyone have issue with this approach?

There hasn't been anyone with an opinion or an alternative to Martin's approach.    As a result, above it what I put into v12:
https://urldefense.proofpoint.com/v2/url?u=https-3A__datatracker.ietf.org_doc_draft-2Dietf-2Dnetconf-2Dsubscribed-2Dnotifications&d=DwICAg&c=HAkYuh63rsuhr6Scbfh0UjBXeMK-ndb3voDTXcWzoCI&r=9zkP0xnJUvZGJ9EPoOH7Yhqn2gsBYaGTvjISlaJdcZo&m=nPdmcQiJgwYaRYnXOWJQJmL0npaAmtTIQk4YNutZA1I&s=Hwcw85WOjJ9Duzi44YtoggL7NZpDaVVRlJVV6HeziKA&e= 

If you feel strongly for please chime in before the end of the week.  If no one chimes in, let's close this issue.

Eric

> Eric
> 
> 
> 
> > From: Martin Bjorklund <[e-mail]>
> > Sent: Thursday, March 22, 2018 3:14 PM
> > To: Eric Voit (evoit) <[e-mail]>
> > Cc: [e-mail]
> > Subject: Re: [Netconf] mbj's WGLC comments on
> > subscribed-notifications-
> > 10
> >
> > Hi,
> >
> > [pruning to open issues]
> >
> >
> > "Eric Voit (evoit)" <[e-mail]> wrote:
> > > Hi Martin,
> > >
> > > Thanks very much for the comments.  Thoughts are in line.  Also a
> > > few key areas marked with "****"
> > >
> > > Note that changes shown below are also included in this working
> > > version
> > > https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_netconf-2Dwg_rfc5277bis_blob_master_draft-2Dietf-2D&d=DwICAg&c=HAkYuh63rsuhr6Scbfh0UjBXeMK-ndb3voDTXcWzoCI&r=9zkP0xnJUvZGJ9EPoOH7Yhqn2gsBYaGTvjISlaJdcZo&m=nPdmcQiJgwYaRYnXOWJQJmL0npaAmtTIQk4YNutZA1I&s=Do-8-gNbbkSGICRHwztUIZKhbaErQvFYlrCnmrlKvGQ&e=
> > netcon
> > > f-subscribed-notifications-11.txt
> > >
> > > > Martin Bjorklund, March 15, 2018 5:12 AM
> > > >
> > > > Hi,
> > > >
> > > > Here are my WGLC comments on
> > > > draft-ietf-netconf-subscribed-notifications-10.
> > > >
> > > > In general, I think ths document has improved a lot, it is now
> > > > easier to follow.
> > > >
> > > >
> > > >
> > > > Major issue
> > > > -----------
> > > >
> > > > o  list receiver
> > > >
> > > >    In the YANG model, the "receiver" list is indexed by ip and port.
> > > >
> > > >    How is the server supposed to use this simple list of ip/port?
> > > >
> > > >    We get a hint from the document in 2.5.2:
> > > >
> > > >      transport specific
> > > >      call-home operations will be used to establish the connection
> > > >
> > > >    But it is not clear that this list of ip/port helps.
> > >
> > > Actually, the address is of type Host.  Of course for everyone must
> > > eventually resolve to an IP address to make a connection.
> > >
> > > However what I think what you are ultimately trying to do is make
> > > sure the choice of index doesn't preclude future mechanisms for
> > > referencing receivers beyond address+Port.  And this likely is a good
> idea.
> > >
> > > >    The document
> > > >    draft-ietf-netconf-netconf-client-server provides configuration for
> > > >    call home for NETCONF.  In that document, the receiver is
> > > >    identified with a "netconf-client" name and an "endpoint" name, not
> > > >    ip/port. (draft-ietf-netconf-restconf-client-server has a similar
> > > >    structure for RESTCONF).
> > >
> > > Yes, having alternative, indirect ways of *ultimately* getting to IP
> > > address + port would help flexibility.
> > >
> > > >    The best solution would have been to have leafrefs to these
> > > >    datamodels, but if we do that now, it would introduce a delay b/c
> > > >    of the dependency.
> > > >
> > > >    The second best solution (I think) is to change this list to have
> > > >    just a "name" as the single key, and nothing else, and write that
> > > >    transport-specific modules can add to this in the future.
> > >
> > > I am fine with name as a single key.  However "nothing else" injects
> > > a few problems:
> > >
> > > (1) our traffic counters are transport agnostic.  Displacing them to
> > > a transport draft reduces utility.
> >
> > Yes; my mistake, I didn't mean to exclude the counters / state /
> > action.  Just host/port.
> >
> > > (2) forcing the acquisition of host or ip address only from the
> > > transport draft creates unnecessary complexity for people who are
> > > able to simply configure host+Port, should it be available in that
> > > form already?  So why not simply leave those in as a transport
> > > agnostic option of last resort should it be available to populate?
> >
> > I think it is a bad idea to include open-ended objects just b/c "maybe
> > someone would like to use them for something".  For interoperability,
> > it is important that all objects we define have clear semantics, and
> > that it clear how to use them.
> >
> > In this case, none of the standard transports will need these nodes
> > (unless the client-server models are severly changed).  If someone
> > defines a transport in the future that needs these objects, it is
> > trivial to do, and it will be done in a more robust way.
> >
> > This said, if the WG strongly believes that these nodes are important,
> > here's a design that might work:
> >
> >   identity inline-address {
> >     description
> >       "A transport identity can derive from this identity in order
> >        to allow inline definition of the host address in the
> >        'receiver' list";
> >     }
> >   }
> >
> >   ...
> >
> >   leaf address {
> >     when 'derived-from(../../../transport, "sn:inline-address")';
> >     ...
> >   }
> >
> > The you can define your transport like this:
> >
> >   identity my-udp-based-transport {
> >     base sn:transport;
> >     base sn:inline-address;
> >   }
> >
> > I would prefer to simply leave this out though.
> 
> 
> 
> 
> 
> 
> 
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