I have reviewed this document as part of the security directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written primarily for the benefit of the security area directors. Document editors and WG chairs should treat these comments just like any other last call comments. Summary: I have found no issues with the document. This I-D defines two new code points for encoding information in BGP-LS messages. The code points are for maximum segment depth of nodes and links. BGP-LS can deliver this information to a centralized controller that needs it to compute a segment routing path. Without this information, the centralized controller may compute routes that won't work. As noted in Security Considerations, supplying incorrect information using this protocol could cause a centralized controller to compute non-optimal or non-working routes, but so could errors in many other fields of this information. These new fields don't introduce any new security challenges beyond those already present in BGP-LS. Radia