[Idr] Shepherd's report on draft-ietf-idr-sr-policy-nrp-04

[Susan Hares <[e-mail]>]

draft-ietf-idr-sr-policy-nrp-04
date: 12/12/2025
Reviewer: Susan Hares
Status: Needs -05 draft before publication request.

Shepherd's Detailed review:

Major: None

Minor issues:
1) RTG-DIR comment should be resolved.
https://datatracker.ietf.org/doc/review-ietf-idr-sr-policy-nrp-03-rtgdir-early-rogge-2025-07-28/

The question is whether NRP ID in draft-ietf-idr-sr-policy-nrp-04
is a control plane ID or a data plane ID.  There is no indication of
NRP ID in BGP Tunnel Encapsulation Attribute Sub TLV  being different than NRP in the data plane.

In my discussions with the authors during  WG LC, they suggested that NRP ID in
the NRP SubTLV is a control plane ID.

draft-ietf-idr-sr-policy-nrp-04 references draft-jiang-spring-sr-policy-nrp-04
to answer this question.  I expected to see this answer clearly laid out
in draft-jiang-spring-sr-policy-nrp-04.   It is not 100% clear, but
this can be fixed by clearly stating in draft-ietf-idr-sr-policy-nrp-05
that it is a control plane NRP ID which is mapped to the data plane NRP ID.

After reviewing the following document
draft-ietf-idr-sr-policy-nrp-04
draft-ietf-idr-bgp-ls-policy-nrp-02
draft-jiang-spring-sr-policy-nrp-04
draft-ietf-pce-pcep-nrp-00
draft-ietf-6man-enhanced-vpn-vtn-id-012,
draft-ietf-mpls-mna-nrp-selector-00, and
draft-ietf-teas-nrp-scalability-07

In my discussions with the authors during
WG LC, they suggested that NRP ID in
the NRP SubTLV is a control plane ID.

To make sure there are no additional questions during Ketan's review,
I sent a summary of my understanding of the NRP ID in BGP
as a control plane to IDR, PCE, Spring and TEAS.
I am waiting until 12/19 for an objection to this understanding.

The email link to the email thread
https://mailarchive.ietf.org/arch/msg/idr/SyvJfNr27HWj5gdETxW_7GpkZU8/

Minor Issue 2) Textual issues impact the meaning in section 2, paragraph 3,

Old text: /
   When the NRP sub-TLV is carried in the BGP Tunnel Encapsulation
   Attribute of an SR Policy NLRI, a segment list of the candidate path
   is considered invalid if the headend node of the SR Policy determines
   that the set of network resources corresponding to the NRP ID on
   network segments identified by the segment list do not exist. /

New text: /
   When the NRP sub-TLV is carried in the BGP Tunnel Encapsulation
   Attribute associated with SR Policy NLRI, a segment list of the candidate path
   is considered invalid if the headend node of the SR Policy determines
   that the set of network resources corresponding to the NRP ID on
   network segments identified by the segment list do not exist. /


Minor Issue 3) Editorial impacts the meaning in section 4, paragraph 2.

Old text:/ If the
   NRP sub-TLV appears more than once, or its format is considered
   malformed, the associated BGP SR Policy NLRI is considered malformed
   and the "treat-as-withdraw" strategy of [RFC7606] MUST be applied.

Old text:/  If the
   NRP sub-TLV appears more than once, or its format is considered
   malformed, the Tunnel Encapsulation Attribute associated
   with a BGP SR Policy NLRI is considered malformed
   and the "treat-as-withdraw" strategy of [RFC7606] MUST be applied./

Sue Hares