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. This memo describes an optional addition to the "two-way actual measurement protocol" (TWAMP) which allows certain monitoring such as congestions. The security considerations sections seems adequate and refers to the core documents for threat models and mitigations. /M