Fleksibilni Internet servisi na bazi kontrole kašnjenja i

RED has been designed to cooperate with TCP’s congestion control algorithm.
TCP flows recognize packet losses as a sign of congestion and reduce their sending rate.
RED begins to drop packets before the buffer overflows and, thus, provides an early
feedback about congestion level on the output link and allows TCP flows to react in a
timely manner. The interval where average queue sizes lie between qmin and qmax is called
early drop region.
In [4], two types of RED control have been defined depending on the slope of the
function p = H (q)
in the early drop region: drop-conservative and delay-conservative. A
drop-conservative RED control results in lower packet loss probability and larger delay.
To the contrary, a delay-conservative RED control results in higher packet loss
probability and lower delay. In the case of FCFS scheduling, queuing delay is always
proportional to the average queue size q . The idea employed in BEDS is illustrated in
Fig. 5.
Fig. 5. The intersections of RED control functions and queue law determine average queuing delays
and average loss probabilities of traffic classes in BEDS.
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