{"draft":"draft-ietf-rtgwg-segment-routing-ti-lfa-21","doc_id":"RFC9855","title":"Topology Independent Fast Reroute Using Segment Routing","authors":["A. Bashandy","S. Litkowski","C. Filsfils","P. Francois","B. Decraene","D. Voyer"],"format":["HTML","TEXT","PDF","XML"],"page_count":"23","pub_status":"PROPOSED STANDARD","status":"PROPOSED STANDARD","source":"Routing Area Working Group","abstract":"This document presents Topology Independent Loop-Free Alternate\r\n(TI-LFA) Fast Reroute (FRR), which is aimed at providing protection\r\nof node and Adjacency segments within the Segment Routing (SR)\r\nframework. This FRR behavior builds on proven IP FRR concepts being\r\nLFAs, Remote LFAs (RLFAs), and Directed Loop-Free Alternates (DLFAs).\r\nIt extends these concepts to provide guaranteed coverage in any\r\ntwo-connected networks using a link-state IGP. An important aspect of\r\nTI-LFA is the FRR path selection approach establishing protection\r\nover the expected post-convergence paths from the Point of Local\r\nRepair (PLR), reducing the operational need to control the tie-breaks\r\namong various FRR options.","pub_date":"October 2025","keywords":["TILFA","LFA","FRR","fast reroute","recovery","SR","protection","convergence"],"obsoletes":[],"obsoleted_by":[],"updates":[],"updated_by":[],"see_also":[],"doi":"10.17487\/RFC9855","errata_url":null}