I am an assigned INT directorate (early) reviewer for draft-ietf-rtgwg-segment-routing-ti-lfa-09.txt. These comments were written primarily for the benefit of the Internet Area Directors. Document editors and shepherd(s) should treat these comments just like they would treat comments from any other IETF contributors and resolve them along with any other Last Call comments that have been received. For more details on the INT Directorate, see https://datatracker.ietf.org/group/intdir/about/ <https://datatracker.ietf.org/group/intdir/about/>.

Based on my review, if I was on the IESG I would ballot this document as NO OBJECTION.

The document is well written, and clear for a reader who has previous knowledge of both Segment Routing and Fast Rerouting mechanism, which is my case. Yet, I have some remarks to do on the document. 

In section 6, you present the scheme of an example network that you use to present TI-LFA Repair path. In the explanation you give about finding the P and Q spaces, I think the reader would benefit from a picture showing the shortest path tree from S and the reverse shortest path tree to D to better understand why P and Q are as stated (in particular for P(S, N1) since R1 is not a direct neighbor of S).

In section 7, the several cases that a PLR will face while building the TI-LFA repair segment list are presented, but this presentation would benefit from examples of topologies and before / after segment lists that would help the reader get the principle of the building method suggested by the document.  

In section 12, while I highly appreciate the effort made by the authors to present measurements about the potential benefit of TI-LFA, I felt (a bit) frustrated by the fact that the topologies are presented but not made available for the reader to look at them in details and to assess the results presented in the document against a potential implementation he would make. I know that publishing such topologies is difficult, so I would suggest that at least one or two publicly available topologies (for instance from the Internet Topology Zoo (http://www.topology-zoo.org/) or from the Defo dataset (https://sites.uclouvain.be/defo/)) are investigated so a motivated and curious reader could try for him/herself.