Security review of Session Initiation Protocol (SIP) Event Notification Extension for Notification Rate Control draft-ietf-sipcore-event-rate-control-05 Do not be alarmed. 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 document specifies mechanisms for adjusting the rate of Session Initiation Protocol (SIP) event notifications. These mechanisms can be applied in subscriptions to all SIP event packages. Subscribers can specify minimum and maximum rates. The rate can change smoothly and adaptively while maintaining an average rate requested by the subscriber. The security considerations for this document are inherited from a prior document about SIP security and seem adequate for the purposes of this document. Hilarie Orman