[Gen-art] Genart last call review of draft-ietf-idr-deprecate-as-set-confed-set-17

[Ines Robles via Datatracker <[e-mail]>]

Reviewer: Ines Robles
Review result: Almost Ready

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Document: draft-ietf-idr-deprecate-as-set-confed-set-17
Reviewer: Ines Robles
Review Date: 2025-02-17
IETF LC End Date: 2025-02-17
IESG Telechat date: 2025-03-06

Summary:

The draft prohibits the use of the AS_SET and AS_CONFED_SET path segment types
in the AS_PATH. It distinguishes between two aggregation methods:

• Traditional brief aggregation (as defined in RFC 4271) aggregates routes by
combining differences in the AS_PATH into an unordered AS_SET (or
AS_CONFED_SET). This approach can leave the route’s origin ambiguous.

• Consistent brief aggregation avoids this ambiguity by deliberately truncating
the AS_PATH at a designated origin AS. By doing so, it does not use AS_SET or
AS_CONFED_SET, resulting in an unambiguous route origin.

This document updates RFC 4271 by deprecating the origination of BGP routes
with AS_SET (Type 1 AS_PATH segment) and updates RFC 5065 by deprecating the
origination of BGP routes with AS_CONFED_SET (Type 4 AS_PATH segment). It also
obsoletes RFC 6472.

The document is well written, and I have some questions:

1- Consistent Brief Aggregation: What operational considerations or guidelines
do you suggest for selecting the designated origin AS in environments where
multiple candidate origins exist, such as in multi-homed or proxy aggregation
scenarios?

2- In cases where consistent brief aggregation results in an empty AS_PATH, is
attaching the ATOMIC_AGGREGATE attribute sufficient to handle the resulting
loss of AS_PATH information? Or should operators implement additional measures
to ensure proper route validation and loop prevention?

Thanks for this document.

Ines