[rtgwg] RFC 9855 on Topology Independent Fast Reroute Using Segment Routing

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        RFC 9855

        Title:      Topology Independent Fast Reroute Using 
                    Segment Routing 
        Author:     A. Bashandy,
                    S. Litkowski,
                    C. Filsfils,
                    P. Francois,
                    B. Decraene,
                    D. Voyer
        Status:     Standards Track
        Stream:     IETF
        Date:       October 2025
        Mailbox:    abashandy.ietf@gmail.com,
                    slitkows@cisco.com,
                    cfilsfil@cisco.com,
                    pierre.francois@insa-lyon.fr,
                    bruno.decraene@orange.com,
                    daniel.voyer@bell.ca
        Pages:      23
        Updates/Obsoletes/SeeAlso:   None

        I-D Tag:    draft-ietf-rtgwg-segment-routing-ti-lfa-21.txt

        URL:        https://www.rfc-editor.org/info/rfc9855

        DOI:        10.17487/RFC9855

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 Directed Loop-Free Alternates (DLFAs).
It extends these concepts to provide guaranteed coverage in any
two-connected networks using a link-state IGP. An important aspect of
TI-LFA is the FRR path selection approach establishing protection
over the expected post-convergence paths from the Point of Local
Repair (PLR), reducing the operational need to control the tie-breaks
among various FRR options.

This document is a product of the Routing Area Working Group Working Group of the IETF.

This is now a Proposed Standard.

STANDARDS TRACK: This document specifies an Internet Standards Track
protocol for the Internet community, and requests discussion and suggestions
for improvements.  Please refer to the current edition of the Official
Internet Protocol Standards (https://www.rfc-editor.org/standards) for the 
standardization state and status of this protocol.  Distribution of this 
memo is unlimited.

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