Hi Yisong, Alvaro, SPRING WG I think Alvaro summarized it well with this point:
* the document is a more detailed version of the example in §3.2/draft-karboubi-spring-sr-policy-eligibility. From my perspective: draft-liu-spring-sr-policy-flexible-path-selection to me describes the parameters and rules on when/why someone may want to make a candidate path not eligible. i.e it’s a use case with local decisions/rule/policy/automated system etc. and the document does a good job describing in detail why/what kind of rules and outcome one would want. draft-karboubi-spring-sr-policy-eligibility is trying to focus on describing the eligibility knob and the changes required to the SR Policy information model (despite it being the smallest block of text in the document - section 4) that any use case, rules, local decision etc. may leverage. The use cases described in the draft are for some examples only and is not exhaustive. To me, the overlap happens with draft-liu-spring-sr-policy-flexible-path-selection being another (detailed) example on the value of defining eligibility in the SR Policy information model (draft-karboubi-spring-sr-policy-eligibility). Thanks Andrew From: Alvaro Retana <[email protected]> Date: Wednesday, November 19, 2025 at 8:37 AM To: Yisong Liu <[email protected]>, spring-chairs <[email protected]>, spring <[email protected]> Cc: draft-liu-spring-sr-policy-flexible-path-selection <[email protected]> Subject: [spring] Re: Follow-up on IETF 124 Presentation of draft-liu-spring-sr-policy-flexible-path-selection and draft clarification CAUTION: This is an external email. Please be very careful when clicking links or opening attachments. See the URL nok.it/ext for additional information. On November 18, 2025 at 8:26:51 PM, Yisong Liu wrote: Yisong: Hi! How are you? > Thank you for the valuable feedback following our presentation at > IETF 124. We would like to offer some clarification to ensure our > draft's purpose is properly understood. > > In our latest revision, we have referenced > draft-karboubi-spring-sr-policy-eligibility, though we wish to > emphasize that the two drafts serve distinctly different purposes. > The eligibility draft introduces new concepts for path qualification, > while our draft focuses specifically on defining a mechanism for path > selection and switching based on forwarding performance metrics such > as latency, jitter, and bandwidth. Our approach predefines quality > requirements for SR policies and enables rapid path selection or > switching when real-time monitoring indicates these requirements are > no longer met. The reference to eligibility is included to maintain > compatibility with the SR Policy architecture defined in RFC 9256. > > We believe there is no significant overlap between our draft and > eligibility draft and see value in advancing them independently. I understand what you're saying, but I am having a hard time seeing that reflected in the document. (1) From §4: When a candidate path fails to meet forwarding quality requirements, its Eligibility attribute SHOULD be set to false, thereby excluding it from active candidate path selection. This text is effectively the same as what draft-karboubi-spring-sr-policy-eligibility says in §3.2 (Example 2: Delay sensitive paths): ...the policy could have a constraint to not use a path when its end-end delay exceeds a given value D1. ... In this case, a system could set the eligibility as false when it detects that path delay exceeds D1 (e.g. using STAMP) rendering path ineligible for selection... The main difference I see is that draft-karboubi-spring-sr-policy-eligibility focuses the example on delay, while your document mentions other possible "threshold parameters" (§4.1). Your document also includes examples in §4.1 and §5. If I may go further, the document is a more detailed version of the example in §3.2/draft-karboubi-spring-sr-policy-eligibility. The comments at the meeting in Montreal also mentioned a "high amount of overlap" (even from one of the authors of this document). (2) From above: "our draft focuses specifically on defining a mechanism for path selection and switching based on forwarding performance metrics". A mechanism is described in §4.3 (Flexible Candidate Path Selection Process): 1) The document mentions that a "headend may be informed about the forwarding quality requirements...through various means", and points at BGP and PCEP drafts (§4). 2) Examples of how the path can be monitored are listed in §4.3, but I see no specification...only examples. 3) The Rules for Setting the Eligibility Attribute (§4.2) are basically the same as what is defined in draft-karboubi-spring-sr-policy-eligibility: if the constraints are met, set the Eligibility to True; otherwise, it can be set to False. 4) Finally, "whether to revert to the previous active candidate path can be specified by the configuration" is mentioned as a possibility, but no explicit specification. In summary, if the intent is to define/specify a mechanism, there's significant work to be done, given that the document only mentions examples at this point. The current content does not justify the Intended Status of putting this document in the Standards Track. > We would appreciate if the chairs can give the guidance on how to > proceed with our draft. Additionally, we have formally requested an > adoption call during our presentation and would be grateful if the > chairs can help to schedule this. In addition to the comments above, the main action item at this time is to build WG engagement and interest. I only found comments from one other non-author in the archive (Joel) [1]. We need to see explicit engagement and interest [2] before moving forward. Thanks! Alvaro. [1] https://mailarchive.ietf.org/arch/search/?q=%22draft-liu-spring-sr-policy-flexible-path-selection%22&f_list=spring [2] https://wiki.ietf.org/en/group/spring/WG_Policies
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