This Notification is sent when an intercepting router or switch is first capable of intercepting a packet corresponding to a configured data stream. The value of the corresponding pktcEScTapStreamType which identifies the actual intercept stream type is included in this notification. This notification may be generated in conjunction with the intercept application, which is designed to expect the notification to be sent as reliably as possible, e.g., through the use of a finite number of retransmissions until acknowledged, as and when such mechanisms are available; for example, with SNMPv3, this would be an InformRequest. Filter installation can take a long period of time, during which call progress may be delayed.