Reviewer: Sheng Jiang Review result: Has Nits Hi, OPS-DIR, Authors, I have reviewed this document as part of the Operational directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written with the intent of improving the operational aspects of the IETF drafts. Comments that are not addressed in last call may be included in AD reviews during the IESG review. Document editors and WG chairs should treat these comments just like any other last call comments. This standard stack document describes the use of certificates in establishing authority over telephone numbers, as a component of a broader architecture for managing telephone numbers as identities in protocols like SIP. This document is well written. It is ready with minor nits. Major issue: no. Nits issue: RFC 8017, RFC 8224 and RFC 8225 are NOT the registered downref. They are normative reference to Informational RFCs. Regards, Sheng