[onions] Re: YANG based Interface integration with TMF Open APIs

[Vance Shipley <[e-mail]>]

On Thu, Jun 5, 2025 at 8:11 PM Kristian Larsson <[e-mail]> wrote:
> Feel free to enlighten me, but I believe that while the TMF APIs might enable mapping the network in whatever detail required, it doesn’t actually model any details of the network at any level. It is left as an exercise for the network operator.

True, there is no "L3VPN" API, or anything like that. There are domain
(P/S/R) specific APIs for Catalog, Inventory, Ordering, Activation,
etc.. Everything fits together cohesively by applying the patterns
consistently. In the Resource domain an L3VPN would be described by a
Resource Function Specification and instantiated as a Resource
Function. So we don't create an L3VPN Ordering API, etc.. we just use
the Specification with the generic APIs (e.g. TMF652 Resource Order,
TMF664 Resource Function Activation, etc.).

I am greatly sympathetic with the lament of "It is left as an exercise
for the network operator". I have been lobbying within TM Forum, as a
contributing member, for them to publish Service/Resource
Specifications, as JSON objects, for common use case examples. If not
normative at least an informative asset would provide a chance of
reducing the replicated integration costs incurred by each network
operator and provide a decent chance of interoperable implementations,
which is otherwise zero.

> The IETF YANG models, for device and for services, already have the actual content modeled. It’s been a long and painstaking process that’s taken years to produce those models. I want to leverage that for these TMF interfaces so we can quickly make progress.

Agreed. I see the process conceptually as:
    1) map a YANG data model to an information model
    2) map that information model to the TM Forum information model (SID)
    3) map that onto applicable TM Forum Open APIs
I documented that process for 3GPP NRMs in IG1217:
https://www.tmforum.org/resources/reference/ig1217-resource-inventory-of-3gpp-nrm-for-service-assurance-v1-0-0/

> It would be good if you and others with TMF knowledge can guide where best to map IETF service models, like L3VPN, into TMF as resources or services.

I will be pleased to contribute to that effort.

> Yes, and I’m suggesting that we drive the production of those service / resource specifications in a model-driven fashion from the YANG models with a minimal set of extra parameters.

I suggest we work on the conceptual mapping and once agreed codify
that in tooling.

--
Vance Shipley, SigScale