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3.2.6 Timer Events

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This protocol has the following RTCP-related timer event processing rules, in addition to those specified in [RFC3550] section 6.2.

RTCP send timer expires: If BandwidthEstSendingMode is "packet pair", a new RTCP packet pair is prepared and sent to the network destination. If BandwidthEstSendingMode is "packet train", a new RTCP packet train is prepared and sent to the network destination. All packets in the RTCP packet pair or RTCP packet train MUST be sent back-to-back; that is, the next one immediately after the previous one. Restart the timer. If the RTCPSendingRate is "normal", compute a new value for this timer according to [RFC3550] Section 6.2. If the RTCPSendingRate is "packet pair fast", set the timer to 250 milliseconds, increment FastRTCPPacketPairCount by 1, and if that counter reaches 40, set RTCPSendingRate to "normal". If the RTCPSendingRate is "packet train fast", set the timer to 1 second, increment FastRTCPPacketTrainCount by 1, and if that counter reaches 21, set RTCPSendingRate to "normal". If a report is being sent in the compound packet as a part of RTCP packet pair or RTCP packet train, a bandwidth estimation profile extension SHOULD be attached to each report. The sender can stop sending RTCP probe packets, which means it begins sending only RTCP Compound packets, if it determines that the receiver does not support processing of these packets.

RTCP Bye timer expires: The information associated with the SSRC that started this timer is deleted. If any packet from the same SSRC arrives after the timer has expired, this SSRC is treated as a new participant.

Packet loss notification timer expires: No action required. If a packet loss is detected after the timer has expired, the algorithm in section 3.2.7 detects that the timer is expired and sends a new packet loss notification.

RTCP feedback message fast timer expires: The RTCP feedback message is resent and the timer is reset. After resending the message 4 times, this timer stops. If the feedback message is a Source Request (SR) message, a RTCP feedback message slower timer SHOULD be started.

RTCP feedback message slow timer expires: The Source Request (SR) message is resent and the timer is reset. After resending the message 4 times, this timer stops.