IETF Last Call Review of draft-ietf-mpls-mldp-yang-16
review-ietf-mpls-mldp-yang-16-opsdir-lc-chen-2026-05-06-00

Hi,

I have been selected as the Operational Directorate (opsdir) reviewer for this
Internet-Draft.

The Operational Directorate reviews all operational and management-related
Internet-Drafts to ensure alignment with operational best practices and that
adequate operational considerations are covered.

A complete set of _"Guidelines for Considering Operations and Management in
IETF Specifications"_ can be found at
https://datatracker.ietf.org/doc/draft-ietf-opsawg-rfc5706bis/.

While these comments are primarily for the Operations and Management Area
Directors (Ops ADs), the authors should consider them alongside other feedback
received.

- Document: draft-ietf-mpls-mldp-yang-16

- Reviewer: Ran Chen

- Review Date: 2026-05-06

- Intended Status: Standards Track

---

## Summary

Choose one:

- Has Issues: I have some minor concerns about this document that I think
should be resolved before publication.

## General Operational Comments Alignment with RFC 5706bis

Provide an overview of the draft’s operational feasibility, readability, and
alignment with RFC5706bis guidelines. Example:

> This document defines a YANG model for mLDP. While the technical approach is
sound, the document lacks an "Operational Considerations" section as required
by RFC5706bis for new protocol extensions (including YANG models).

> The Operational Considerations section (to be added before Security
Considerations) could be expanded to discuss the migration path from the base
LDP YANG model (RFC 9070).

## Major Issues

 > No major issues found.

---

## Minor Issues

1.MBB and MoFRR statistics – While the model already provides configuration and
state (active/standby role) for MBB and MoFRR, it does not yet include counters
for MBB switch events, last switch time, or MoFRR primary/backup switches. The
authors may wish to consider adding these statistics to help operators monitor
the health of protection mechanisms.

2.RFC 9070 already provides message‑level statistics, which are helpful for
monitoring the general health of LDP sessions. In operational practice, it can
also be valuable to understand, per LDP session, how many FECs of specific
types (e.g., P2MP, MP2MP Upstream, MP2MP Downstream) are sent or received. Such
information could be useful for capacity planning and detecting anomalous
trends. The current mLDP model does not yet include per‑session FEC counters
broken down by these types. If the authors consider adding such counters, it
would offer extra benefits for capacity planning and anomaly detection. This is
entirely at their discretion and is not a requirement of this review.
---

## Nits

section 3.1
- "Transit Birdir"->"Transit Bidir"
- "specifc" -> "specific".
section 6.2.1
-"a opaque"->"an opaque"
---

Thanks!
Ran