[Teas] Re: WG Last Call: draft-ietf-teas-actn-pm-telemetry-autonomics-18 (Ends 2026-07-31)

[Vishnu Pavan Beeram <[e-mail]>]

{as a WG participant}

Authors,

I've reviewed draft-ietf-teas-actn-pm-telemetry-autonomics-18 as part of
the WGLC. Below are my comments -

1. Section 1, para 5: "via a NETCONF [RFC8341] or a RESTCONF [RFC8040]
interface" — RFC 8341 is NACM (access control model), not NETCONF. The
correct reference is RFC 6241, which is used correctly elsewhere in the
document.

2. Section 3.1, last line: "(See Section 6 for details)" — Section 6 is
"Notification" which states "This model does not define specific
notifications." The auto-scaling details are in Sections 4 and 7.

3. Section 4, paragraph after Figure 5: "whose model is presented in full
detail in Sections 6 & 7" — The full tree is in Section 8 and the full
model is in Section 9. Sections 6 & 7 are Notification and Scaling Examples.

4. Section 4, bullet list mentions "MIN, MAX, etc." as valid
scaling-operation-type values, but the `scaling-criteria-operation` typedef
only defines AND and OR. MIN and MAX are not valid. The text is
inconsistent with the model.

5. Section 4, "List 2" example: "threshold-value: w megabytes"
(threshold-value is of type scale-value which is in turn a union of
different types) — The `utilized-bandwidth` identity description says the
threshold-value is interpreted as "bytes per second." Using "megabytes"
here contradicts the model.

6. YANG module `ietf-vn-telemetry`: RFC Editor note says
"draft-lee-teas-pm-telemetry-autonomics becomes an RFC" — this should be
"draft-ietf-teas-actn-pm-telemetry-autonomics".

7. YANG module `ietf-te-telemetry`: RFC Editor note says
"draft-ietf-teas-pm-telemetry-autonomics becomes an RFC" — missing "actn-"
in the name.

8. Both YANG modules have "Copyright (c) 2025 IETF Trust" but the document
copyright says "Copyright (c) 2026 IETF Trust". The YANG modules should be
updated.

9. Figure 4 caption says "TE Telemetry Model Interactions" but the figure
shows VN-level grouping operations across VN members. It should be "VN
Telemetry Model Interactions".

10. The model defines identities for `one-way-delay-variation` and
`two-way-delay-variation` (usable in scaling thresholds), but the telemetry
read-only container (from `performance-metrics-attributes` in RFC 8776)
only reports delay and not delay-variation in the two-way direction. The
draft should reference draft-ietf-teas-rfc8776-update instead which
addresses this.

11. Section 6 is titled "Notification" but immediately says "This model
does not define specific notifications." The section actually describes
YANG Push subscriptions. Consider a title like "Telemetry Subscription
Mechanism."

12. No RFC 2119/8174 boilerplate or normative keywords (MUST, SHALL,
SHOULD) appear anywhere in the document. For a Standards Track document
defining YANG models, this is unusual. Are there no conformance
requirements?

13. The model defines scaling *intent* (thresholds, conditions, operations)
but provides no specification of what "scale-in" or "scale-out" actually
does. `scale-in-op` defaults to DOWN, `scale-out-op` defaults to UP — but
what does UP/DOWN mean operationally? Increase bandwidth by the `scale`
value? Re-optimize to a less constrained path? Something else? Without
behavioral specification, interoperability is questionable.

14. No discussion of what happens when both scale-in and scale-out
conditions are met simultaneously (e.g., due to oscillation or conflicting
thresholds). Cooldown-time helps, but there's no statement about precedence
or mutual exclusion.

15. Section 1, para 3: "MSDC" should likely be "MDSC" (Multi-Domain Service
Coordinator) per RFC 8453 terminology. Letters appear transposed.

16. Section 3, item (i): "which provides the TE-Tunnel level of performance
monitoring mechanism" — remove "of" for correct grammar: "which provides
the TE-Tunnel level performance monitoring mechanism".

17. Section 3, item (ii): Missing period after "(See Section 3.2 & Section
9.2 for details)".

18. Section 3.1, last sentence: Missing period after "(See Section 6 for
details)".

19. Both YANG modules list "Young Lee" as Editor in the contact field, but
Young Lee is not a document author — only acknowledged. The contact should
list the actual document editor (Dhruv Dhody).

20. XML examples (Figures 7-8) use namespace
`urn:ietf:params:xml:ns:yang:ietf-yang-push:1.0` — the correct namespace
from RFC 8639 is
`urn:ietf:params:xml:ns:yang:ietf-subscribed-notifications`.

21. XML examples (Figures 9-12) use identity values like
`<performance-type>two-way-delay</performance-type>` without namespace
qualification. In NETCONF, identity values need prefixed names or proper
namespace context.

I'd suggest these be addressed before progressing.

Regards,
-Pavan

On Fri, Jul 10, 2026 at 4:30 PM Vishnu Beeram via Datatracker <
[e-mail]> wrote:

> This message starts a WG Last Call for:
> draft-ietf-teas-actn-pm-telemetry-autonomics-18
>
> This Working Group Last Call ends on 2026-07-31
>
> Abstract:
>    This document provides YANG data models that describe the performance
>    monitoring parameters and scaling intent mechanisms for Traffic
>    Engineering (TE) tunnels and Virtual Networks (VNs).  Their
>    performance monitoring parameters are exposed as the key telemetry
>    data for tunnels and VNs.
>
>    The models presented in this document allow customers to subscribe to
>    and monitor the key performance data of the TE-tunnel or the VN.  The
>    models also provide customers with the ability to program autonomic
>    scaling intent mechanisms on the level of TE-tunnel as well as VN.
>
> File can be retrieved from:
>
> https://www.ietf.org/archive/id/draft-ietf-teas-actn-pm-telemetry-autonomics-18.txt
>
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