http://www.rfc-editor.org/rfc/rfc6446.txt
RFC 6446: Session Initiation Protocol (SIP) Event Notification Extension for Notification Rate Control, A. Niemi, K. Kiss, S. Loreto2012-01-01T23:00:00-00:00This 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. This document updates RFC 3265. [STANDARDS-TRACK]