One or more queues store
data information such as packets or data flows for later transmission to downstream communication devices. A real-time
clock tracks
current time and an advancement of a moving time reference, which is displaced with respect to the
current time of the
clock by an offset value. Thus, as
current time advances, the moving time reference also advances in time. Upon servicing a
queue, a time stamp associated with the serviced
queue is also advanced in time. To monitor a rate of outputting data from the one or more queues, a processor device at least occasionally adjusts the offset value so that the moving time reference and values of the time stamps advance in relation to each other. Consequently, by tracking a relative
time difference between current time of the real-time
clock and a relative advancement of time stamps, a rate of outputting
data information from the
queue is monitored over time.