Re: [netmod] Adoption poll for draft-wwx-netmod-event-yang-10

[Andy Bierman <[e-mail]>]

On Tue, Dec 29, 2020 at 8:26 AM Adrian Farrel <[e-mail]> wrote:

> Hi Juergen,
>
> What you say about learning lessons from the past is wise and valuable.
>
> Sadly (well, it's a good thing, really) we have new people in the IETF and
> the memory of events over the last 20 years are not immediately accessible
> to them. Others, who are old and grey, have been around that long but were
> not necessarily involved in previous ECA discussions.
>
> Since "intent-based networking" is a big thing once again (see recent
> reports of acquisitions in this sector) the excitement about ECA may be
> forgiven, but it would help to ground the discussions if those who can
> remember previous efforts would share their experiences or at least some
> pointers.
>
>
I am not that interested in lessons from the past because it just sounds
like an old-timer's negativity.  But I am not interested in boiling the
ocean either.

There is an invalid assumption with ECA that the current client development
logic
(which is completely unbounded in its complexity, purpose, side effects,
design,
or server interaction model) can somehow be replaced with a highly
constrained
YANG model abstraction.

IMO a script-language-based solution is needed.
The ECA framework is good progress, but Programming in YANG is not.
However the IETF is not well-suited for standardizing programming languages
Open-Source is a much better solution path for this approach.

The solution also has to do a great job of gluing the model components to
the ECA logic and actions so there is maximum reusability and scalability.

Most importantly, it has to be easy for an operator to program and debug
ECA.
There aren't going to be any magic tools to hide the complexity.


Best,
> Adrian
>


Andy


>
> -----Original Message-----
> From: netmod <[e-mail]> On Behalf Of Juergen Schoenwaelder
> Sent: 23 December 2020 18:09
> To: Andy Bierman <[e-mail]>
> Cc: NetMod WG Chairs <[e-mail]>; NETMOD Group
> <[e-mail]>
> Subject: Re: [netmod] Adoption poll for draft-wwx-netmod-event-yang-10
>
> On Wed, Dec 23, 2020 at 07:05:44AM -0800, Andy Bierman wrote:
> > On Wed, Dec 23, 2020 at 3:14 AM tom petch <[e-mail]> wrote:
> >
> > > From: netmod <[e-mail]> on behalf of Dhruv Dhody <
> > > [e-mail]>
> > > Sent: 21 December 2020 17:12
> > >
> > > Hi Lou, WG,
> > >
> > > I find the motivation in the Introduction to be focused on ECA at the
> > > network devices (with all the talk about issues with Centralized
> > > network management).
> > >
> > > I see the value of ECA on the controller as well, say a customer
> > > network controller or an orchestrator can set the ECA on a central
> > > controller (reference ACTN in TEAS WG). Perhaps you would consider
> > > adding a sentence to describe this as well. The client-server
> > > terminology in the rest of the document covers it already.
> > >
> > > And I do see value in this and support adoption.
> > >
> > > <tp>
> > > My take is that the I-D is unclear on what ECA is.
> > >
> > > ECA has been worked on in at least two IETF WG AFAICT.  It cropped up
> in
> > > I2RS but as I recall, it was along the lines of 'This is ECA'  'No It
> is
> > > not'  'Yes it is' which gave me the impression that ECA is not a
> > > well-defined, or well-understood, term.
> > >
> > > More recently, I2NSF have produced a YANG capability-data-model which
> is
> > > 55 pages of ECA.  Lacking a definition in this netmod I-D, I am unclear
> > > what the relationship is between the I2NSF I-D and the netmod I-D,
> whether
> > > or not they are using ECA in the same sense.
> > >
> > >
> > Hi Tom,
> >
> > It usually helps to agree on the problem-space before focusing on the
> > solution-space.
> > ECA seems like a methodology (ala MVC) more than anything else.
> > The problem statement seems to be that some client tasks need to be
> handled
> > on the
> > server using ECA methodology, instead of on the client.
> > Which tasks? Seems to be any task of arbitrary purpose or complexity.
> > And now the scope is supposed to include controllers (just another
> client),
> > so the problem-stmt
> > is even less clear.
> >
> > The traditional approach is to pick specific client tasks to move to the
> > server.
> > The example of detecting and reporting route-flaps has been used.
> > (No ECA example of this complexity has been provided yet).
> > The traditional approach would be to write a route-flap-detection YANG
> > module with some
> > configuration, monitoring data, and notification events.
> >
> > The generalized approach is likely to be extremely complex to standardize
> > and implement.
> >
>
> ECA work has a long 20+ year tradition in the IETF and several
> specifications have been published over the years by various working
> groups. As far as I can tell, none of them got traction in terms of
> signifiant deployment of interoperable implementations.
>
> I would have hoped that the next iteration of ECA work would have
> started with a deep reflection about why all the previous attempts
> failed to gain traction and some genuine insights how to design things
> differently in order to improve the likelihood to have impact.
>
> /js
>
> --
> Juergen Schoenwaelder           Jacobs University Bremen gGmbH
> Phone: [phone]         Campus Ring 1 | 28759 Bremen | Germany
> Fax:   [phone]         <https://www.jacobs-university.de/>
>
> _______________________________________________
> netmod mailing list
> [e-mail]
> https://www.ietf.org/mailman/listinfo/netmod
>
>