[OPS-DIR]draft-ietf-idr-bgpls-inter-as-topology-ext-27 early Opsdir review

[Tina Tsou via Datatracker <[e-mail]>]

Document: draft-ietf-idr-bgpls-inter-as-topology-ext
Title: BGP-LS Extension for Inter-AS Topology Retrieval
Reviewer: Tina Tsou
Review result: Has Nits

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-idr-bgpls-inter-as-topology-ext-27

- Reviewer: Tina Tsou

- Review Date: 4/29/2026

- Intended Status: Standards Track

---

## Summary

Choose one:

- Has Nits: This document is basically ready for publication but has nits that
should be considered prior to publication.

This document extends BGP-LS to support inter-AS topology dissemination. The
technical approach is sound and consistent with existing BGP-LS mechanisms.
However, several operational aspects require clarification to ensure safe and
scalable deployment across administrative domains.

Key Operational Risks
- Inter-AS Information Leakage
Without clear scoping and policy guidance, topology information may
unintentionally propagate beyond intended administrative boundaries. - Scaling
and Control-Plane Load Inter-AS topology exchange can significantly increase
state and churn, especially in large multi-domain deployments. -
Troubleshooting Complexity Lack of guidance on debugging inconsistent or
partial topology views across ASes may complicate fault isolation. - Policy
Interaction Ambiguity Interaction with existing BGP policy controls (filtering,
route selection, export policies) is not clearly defined.

Missing Operational Considerations
- No clear deployment models (e.g., controller-based vs. distributed,
inter-provider scenarios) - Limited discussion of configuration controls
(enable/disable, scoping, filtering) - No guidance on validation and
verification of topology correctness - Insufficient detail on incremental
deployment / backward compatibility - Minimal coverage of monitoring and
telemetry expectations

Recommended Changes (Top 5)
1. Add Deployment Scenarios
Include at least one informative section describing typical inter-AS deployment
models and operator workflows. 2. Define Policy and Scope Controls Clarify how
operators can restrict, filter, or scope inter-AS topology advertisements to
avoid unintended exposure. 3. Enhance Troubleshooting Guidance Provide
operational guidance for detecting and resolving inconsistencies (e.g., missing
links, mismatched topology views). 4. Address Scaling Considerations Add
discussion of expected control-plane impact, including state growth and update
frequency in large-scale deployments. 5. Describe Incremental Deployment
Strategy Explain how these extensions can be deployed gradually across AS
boundaries without requiring full network upgrades.

Major Issues

No major issues found.

Minor Issues
- Clarify terminology consistency (AS vs. domain vs. administrative boundary)
- Add brief operational context to key encoding sections
- Expand discussion on interaction with existing BGP policies

Nits
- Consider adding an example end-to-end inter-AS topology use case
- Minor editorial improvements for clarity and readability

Overall, this is a solid and useful extension to BGP-LS. Addressing the above
points would improve operational clarity and deployability.

Best regards,
Tina Tsou