HP procurve 8100fl series Management And Configuration Manual page 112

QoS Configuration
Using QoS Commands
N o t e
8-6
Queue depths (variables A and B) are expressed in terms of a percentage of
256. Therefore 25% of 256 is 64 and 75% is 192. Queue probability (variable C)
is simply a percentage.
100%
C
67%
0%
0
Figure 8-2. Calculating Random Detect Limits
In Figure 8-2, C represents the drop probability on a scale from 0 to 100%.
A is the amount of queue that is full before WRED is invoked. And B is the
amount of queue that is filled beyond which the drop probability is 100%.
In this mode, you can configure the random-detect command. This command
configures how full the queue needs to be before the queue engine applies, at
what point the drop probability is 1, and what the drop probability percentage
is when the queue is full.
A
Queue Depth
25%
255
B
75%