The SIP event notification framework describes the usage of the Session Initiation Protocol (SIP) for subscriptions and notifications of changes to the state of a resource. The document does not describe a mechanism whereby filtering of event notification information can be achieved. This document describes the operations a subscriber performs in order to put filtering rules associated with a subscription to event notification information in place. The handling@ by the subscriber@ of responses to subscriptions carrying filtering rules and the handling of notifications with filtering rules applied to them are also described. Furthermore@ the document conveys how the notifier behaves when receiving such filtering rules and how a notification is constructed.