Authors, While reviewing this document during AUTH48, please resolve (as necessary) the following questions, which are also in the source file.
1) <!-- [rfced] Please insert any keywords (beyond those that appear in the title) for use on https://www.rfc-editor.org/search. --> 2) <!-- [rfced] FYI - We have made some adjustments to the abstract in order to clarify the expansions of some abbreviations. Please review and let us know if any further updates are necessary. Original: This document presents Topology Independent Loop-free Alternate Fast Reroute (TI-LFA), aimed at providing protection of node and adjacency segments within the Segment Routing (SR) framework. This Fast Reroute (FRR) behavior builds on proven IP Fast Reroute concepts being LFAs, remote LFAs (RLFA), and remote LFAs with directed forwarding (DLFA). Current: This document presents Topology Independent Loop-Free Alternate (TI- LFA) Fast Reroute (FRR), which is aimed at providing protection of node and adjacency segments within the Segment Routing (SR) framework. This FRR behavior builds on proven IP FRR concepts being LFAs, Remote LFAs (RLFAs), and remote LFAs with directed forwarding (DLFAs). --> 3) <!-- [rfced] We were unable to find the term "Directed Loop-Free Alternates (DLFA)" mentioned in RFC 5714. Is there an alternative reference that could be used here? Original: By utilizing Segment Routing (SR), TI-LFA eliminates the need to establish Targeted Label Distribution Protocol sessions with remote nodes for leveraging the benefits of Remote Loop-Free Alternates (RLFA) [RFC7490][RFC7916] or Directed Loop-Free Alternates (DLFA) [RFC5714]. --> 4) <!--[rfced] To improve readability, may we update "makes the requirement unnecessary" to "eliminates the need" in the sentence below? Original: Utilizing SR makes the requirement unnecessary to establish additional state within the network for enforcing explicit Fast Reroute (FRR) paths. Perhaps: Utilizing SR also eliminates the need to establish an additional state within the network for enforcing explicit Fast Reroute (FRR) paths. --> 5) <!-- [rfced] To improve readability, we have reformatted the text that appears at the end of the Introduction into a bulleted list. Please review. In addition, may we adjust these three items for consistency with the other list items (so that each list item begins with the section number it refers to)? Note: The section numbers in this document have changed so they may appear differently in the "Perhaps" text. Original: Using the properties defined in Section 5, Section 6 describes how to compute protection lists that encode a loop-free post-convergence path towards the destination. ... Certain considerations are needed when adjacency segments are used in a repare list. Section 10 provides an overview of these considerations. ... By implementing the algorithms detailed in this document within actual service provider and large enterprise network environments, real-life measurements are presented regarding the number of SIDs utilized by repair paths. These measurements are summarized in Appendix B. Perhaps: * Section 5 describes how to compute protection lists that encode a loop-free post-convergence path towards the destination using the properties defined in Section 4. ... * Section 9 provides an overview of the certain considerations that are needed when adjacency segments are used in a repair list. ... * Appendix B summarizes the measurements from implementing the algorithms detailed in this document within actual service provider and large enterprise network environments. Real-life measurements are presented regarding the number of SIDs utilized by repair paths. --> 6) <!-- [rfced] FYI - The main notations in the Terminology section were formatted inconsistently, so we have reformatted those items into a bulleted list. Please review the changes to the following items in particular: Original: Primary Interface: Primary Outgoing Interface: One of the outgoing interfaces towards a destination according to the IGP link-state protocol Primary Link: A link connected to the primary interface adj-sid(S-F): Adjacency Segment from node S to node F Current: * The primary interface and the primary outgoing interface are one of the outgoing interfaces towards a destination according to the IGP link-state protocol. * The primary link is a link connected to the primary interface. * The adj-sid(S-F) is the adjacency segment from node S to node F. --> 7) <!-- [rfced] To improve readability, may we break up this sentence into two sentences? If yes, would "the path" be the correct subject for the second sentence? Original: The repair list encodes the explicit, and possibly post-convergence, path to the destination, which avoids the protected resource X and, at the same time, is guaranteed to be loop-free irrespective of the state of FIBs along the nodes belonging to the explicit path as long as the states of the FIBs are programmed according to a link-state IGP. Perhaps: The repair list encodes the explicit (and possibly post-convergence) path to the destination, which avoids the protected resource X. At the same time, the path is guaranteed to be loop-free, irrespective of the state of FIBs along the nodes belonging to the explicit path, as long as the states of the FIBs are programmed according to a link-state IGP. --> 8) <!-- [rfced] FYI - We have updated the "0" in "Adj-Sid(R20R3)" to "-". Please review and let us know if further updates are needed. Original: As a result, the TI-LFA repair list of S for destination D considering the failure of node N1 is: <Node-SID(R1), Adj-Sid(R1-R2), Adj-Sid(R20R3)> Current: As a result, the TI-LFA repair list of S for destination D considering the failure of node N1 is: <Node-SID(R1), Adj-Sid(R1-R2), Adj-Sid(R2-R3)>. --> 9) <!--[rfced] May we update "non protected" to "unprotected" in the sentence below? Original: To avoid the possibility of this double FRR activation, an implementation of TI-LFA MAY pick only non protected adjacency segments when building the repair list. Perhaps: To avoid the possibility of this double FRR activation, an implementation of TI-LFA MAY pick only unprotected adjacency segments when building the repair list. --> 10) <!-- [rfced] Terminology: a) We note different formatting and spacing for the following items throughout this document (some examples below). Please review and let us know if/how these items should be made consistent. spacing and apostrophe: P'(R,X) P'(R, X) P(R,X) spacing: [adj-sid(S-F),node(T),...] [adj-sid(S-F), node(T), ...] b) We note different capitalization and hyphenation for the following terms throughout this document (see some examples below). How should these be updated for consistency? Adjacency segment vs. adjacency segment Adjacency SIDs vs. adjacency SIDs Adj-SID vs. Adj-Sid vs. adj-SID vs. adj-sid Node SID vs. Node-SID vs. node-SID P-Space vs. P-space Q-Space vs. Q-space c) May we update all instances of "dataplane" to "data plane" for consistency with RFC 8660? d) FYI - For consistency with RFC 9350, we have updated the terms below as follows: OLD -> NEW FlexAlgo / Flex Algo -> Flexible Algorithm Flex Algo Definition -> Flexible Algorithm Definition --> 11) <!-- [rfced] Abbreviations: a) We note that "DLFA" has been expanded inconsistently throughout the document. For consistency, may we update all of these expansions to be "Directed Loop-Free Alternates"? Original: remote LFAs with directed forwarding (DLFA) DLFA: Remote LFA with Directed forwarding DLFA (LFA with directed forwarding) Directed Loop-Free Alternates (DLFA) Perhaps: Directed Loop-Free Alternates (DLFA) b) Per Section 3.6 of RFC 7322 ("RFC Style Guide"), abbreviations should be expanded upon first use. How may we expand "rSPF" in the text below? Original: ...in all the SPF/rSPF computations that are occurring during the TI-LFA computation. c) Both the expansion and the acronym for the following terms are used throughout the document. Would you like to update to using the expansion upon first usage and the acronym for the rest of the document for consistency? Point of Local Repair (PLR) Repair List (RL) Segment Routing (SR) d) FYI - We have added expansions for the following abbreviations per Section 3.6 of RFC 7322 ("RFC Style Guide"). Please review each expansion in the document carefully to ensure correctness. Segment Routing over MPLS (SR-MPLS) Segment Routing over IPv6 (SRv6) Provider Edge (PE) --> 12) <!-- [rfced] Please review the "Inclusive Language" portion of the online Style Guide <https://www.rfc-editor.org/styleguide/part2/#inclusive_language> and let us know if any changes are needed. Updates of this nature typically result in more precise language, which is helpful for readers. Note that our script did not flag any words in particular, but this should still be reviewed as a best practice. --> Thank you. Kaelin Foody and Alanna Paloma RFC Production Center On Sep 4, 2025, at 9:19 AM, rfc-edi...@rfc-editor.org wrote: *****IMPORTANT***** Updated 2025/09/04 RFC Author(s): -------------- Instructions for Completing AUTH48 Your document has now entered AUTH48. Once it has been reviewed and approved by you and all coauthors, it will be published as an RFC. 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