RTCP Send timer: When the RTCP send rate is "normal", its next value is computed as specified in [RFC3550] section 6.2. When RTCP send rate is fast, its next value MUST be set to 250 milliseconds. This timer is started each time an RTCP compound packet is sent and is used to schedule the sending of the next RTCP packet pairs.
RTCP Bye timer: This timer MUST be set to 2 seconds; it is started when an RTCP BYE is received. There MUST be one timer per participant.