[Pce] Re: WGLC review of draft-ietf-pce-sr-p2mp-policy-19

["Hooman Bidgoli (Nokia)" <[e-mail]>]

Hi Dhruv

Thanks for taking time and going through the draft one more time 😊 ! I will address most of your concerns in the next version of the draft.

Thanks
Hooman

From: Dhruv Dhody <[e-mail]>
Sent: Thursday, August 27, 2026 2:02 PM
To: [e-mail]
Subject: [Pce] WGLC review of draft-ietf-pce-sr-p2mp-policy-19


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Hi,

As a WG participant...

I thank the authors for addressing my previous comments and working to prepare this I-D for publication.

I want to highlight a few remaining points that have not been updated to gauge the group's feedback on these items as well as some newly spotted issues:

1.  Appendix A (https://www.ietf.org/archive/id/draft-ietf-pce-sr-p2mp-policy-19.html#appendix-A) I still find this appendix with a bit level encodings problematic and an unnecessary deviation from standard norms. I prefer the existing example mechanisms used in previous P2MP RFCs, such as RFC 8623 (https://www.rfc-editor.org/rfc/rfc8623.html#section-6.6) This standard approach allows objects and TLVs to evolve without the examples going out of sync.

Hooman previously responded to this, noting that this style of packet sample has helped many readers implement the draft, but mentioned a willingness to remove them if there is a large objection from the WG. I remain unconvinced that the benefit outweighs the maintenance risk and would appreciate feedback from other WG participants.

2.  Appendix B: This section requires additional textual explanation to accompany the figures. Some issues include:

  - The first PCRpt message, which is unsolicited, should not have SRP-ID=1.
HB> ok thanks

  - In the case of PCInitiate with PLSP-ID=1, the text states "PLSP-ID: value MUST be set to zero and will be assigned by PCC."

HB> ok thanks

  - RFC 9960 and Section 4.3.4 recommend installing downstream state before the root, so why is the root RS downloaded first in the PCE-Initiated workflow?

HB> the first PCRpt is to tell the PCE about all the leaves that were discovered via NG-MVPN procedures. That said removed the PCUpd and PCRpt.

  - The MBB workflow seems to mishandle both the instance-ID (as it is always b) and the CC-ID. Please check this thoroughly.

3.  Introduction: The text states, "As per [RFC9960] a P2MP service can be realized by two types of a P2MP Trees, Ingress Replication or a P2MP tree." It is confusing to state there are two types of P2MP trees and then call one of those types simply a "P2MP tree."

HB> ok updated the text. Thanks.


4.  Terminology: Some descriptions feel too loose for a Proposed Standard

  - The use of the term "variant" is confusing. We should be explicit that a new object type is being defined in this document. We do not typically refer to each object-type as a variant; they are still the same object.

HB> changed section 4.2.3 to PCECC and a new format of CCI object is used in …
HB> section 4.1 changed “RFC8231 the bases for a stateful PCE, and reuses the following objects or a new format of the objects”

  - The text claims that the Instance-ID is equivalent to the LSP ID, it is better to state that they serve a similar purpose during MBB.
HB> I removed this.

  - The text states "[RFC3209] Defines the instance-ID", but I could not find that term there.
HB> thanks changed to RFC9960

  - The text states "These PTIs are equivalent to sub-lsps (instance-IDs)." However, a sub-lsp in P2MP is S2L—how is that the same as an instance-id which indicates the PTI?
HB> reworked this entire bulletin as both you and Mike has issues with it


5.  Section 5.1 Figure: The Length=4 value indicated in the figure is incorrect.
HB> thanks changed to 8


6.  Section 5.1 Text: "Upon the receipt of an Open message, the receiving PCEP peer MUST determine whether the suggested PCEP session characteristics (leaf-types) are acceptable." Since there is no way to indicate support for leaf-types, did you intend to reference a different characteristic here? Also, the number of instances is listed as something to negotiate. The text states a maximum of two instances, but the required behavior when the value is >2 or 0 needs more clarity.

HB> cleaned up.


7.  Section 4.3.1: "The PCInitiate message sent to the root MUST set the Tree-ID to 0. If not the PCC must send a PCEP Error message (PCErr) with Error-Type = X2 (SR P2MP Policy General Error) and Error value = 1 (PCInit Invalid Root-ID)." Did you mean "Tree-ID" instead of "Root-ID" in the error description?

HB> cleaned up.


8.  In <sr-p2mp>::=<ENDPOINT>; change <ENDPOINT> to <END-POINTS>.

HB> Thanks


9. Section 5.5.2: "A SR P2MP PCRpt MAY mix different types of Leaf nodes by including several P2MP END-POINTS objects." This is not compatible with our RBNF, which specifies <sr-p2mp>::=<ENDPOINT> (allowing only one).

HB> wouldn’t number 8 fix this issue as well?

10.  Section 4.3.3.1<http://4.3.3.1/>: "If not the PCC must send a PCEP Error message (PCErr) with Error-Type = X2 (SR P2MP Policy General Error) and Error value = 2 (Invalid PLSP-ID)." Why not reuse Error-Type 19 (Invalid Operation) and Error-Value 8 (Non-zero PLSP-ID in LSP Initiate Request)? There are other errors that can be easily reused instead of defining new ones.

HB> ok

11. As Samuel noted, the Instance-ID length and allocation responsibility need to be fixed.
HB> ok


Thanks!
Dhruv