Allied Telesis AlliedWare Plus - Manual (Page 24)

Page 24 | AlliedWare Plus™ OS: Overview of QoS
Note that by default ports only use the maximum threshold, because they are in tail-drop
mode. The other settings are random-detect mode settings. Having defaults means that you
can change to random-detect mode without having to configure a queue set (see
"Applying
RED curves to ports" on page 25 ).
Random-detect mode—using RED
What RED
curves are
The fundamental entity in the switch’s RED curve structure is a single set of minimum
threshold—maximum threshold—drop probability values. These three values define a
“curve” such as the one shown in the following figure.
z Minimum threshold defines the length that the queue must reach before the packets
start being dropped.
z Maximum threshold defines the length that the queue must reach before the shaper
stops dropping randomly, and just drops all further packets.
z Drop probability defines the percentage of packets that are being dropped at the point
when the length of the queue reaches the maximum threshold value. Effectively, the drop
probability defines how quickly the rate of dropping packets must increase as the queue
length grows from the minimum threshold to the maximum threshold.
10G Minimum threshold 1 MB
Maximum threshold 1 MB
Drop probability 50%
Averaging factor 9
Port speed Setting Value
Drop
Minimum
threshold
Maximum
threshold
0%
100%
Dr
op Pr
obability
QoS2.eps