The NOTIFY method is used by a user AGENT to convey information about the occurrence of a PARTICULAR event. A NOTIFY is always sent within a dialog when a subscription exists between the subscriber and the notifier. A NOTIFY request normally receives a 200 OK response to indicate that it has been received. If a 481 Dialog/Transaction Does Not Exist response is received, the subscription is automatically terminated and no more NOTIFYs are sent. NOTIFY requests contain an Event header field INDICATING the package and a Subscription-State header field indicating the current state of the subscription.

The NOTIFY method is used by a user agent to convey information about the occurrence of a particular event. A NOTIFY is always sent within a dialog when a subscription exists between the subscriber and the notifier. A NOTIFY request normally receives a 200 OK response to indicate that it has been received. If a 481 Dialog/Transaction Does Not Exist response is received, the subscription is automatically terminated and no more NOTIFYs are sent. NOTIFY requests contain an Event header field indicating the package and a Subscription-State header field indicating the current state of the subscription.