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 standards track document defines Diameter AVPs that can be used to convey a variety of priority parameters. While the Security Considerations section of this document properly requires that implementers review the Security Considerations section in the Diameter protocol specification and consider the issues described there, it does not include any analysis of the specific security issues related to priority systems. The authors should review other Security Considerations sections relating to priority systems (e.g. the one in RFC 4412) and add text that describes the special security issues that arise with priority systems and the countermeasures that may be employed. Thanks, Steve