Dell Networking 2024 Reference Manual page 677

User Guidelines
The Green/Yellow/Red Ranges may overlap and are applied to each color
independently. Within a color, the range from minimum to maximum is
divided into eight (0...7) fixed probabilities at which packets are dropped
based on the instantaneous egress queue size:
0 - 6.25% of maximum drop probability
1 - 18.75% of maximum drop probability
2 - 30.25% of maximum drop probability
3 - 43.75% of maximum drop probability
4 - 56.25% of maximum drop probability
5 - 68.75% of maximum drop probability
6 - 81.25% of maximum drop probability
7 - 92.75% of maximum drop probability
Packets are dropped at 100% when the queue size exceeds the maximum
value and at 0% when the queue size is below the minimum value.
Configuring a queue with a drop probability of 0% effectively applies tail-drop
behavior when the queue length exceeds the maximum threshold.
If the max thresh parameter is less than the corresponding min-thresh
parameter, it is adjusted to be the min-thresh plus one.
Example
This example configures interface te2/0/1 to drop packets queued for egress
on the all interfaces (global config) or a single interface (interface config)
with a piecewise linear approximation of the configured probability when the
average queue size is within the given range:
• TCP Green Range: 5 to 15% - 1% maximum drop probability
• TCP Yellow Range: 10% to 25% - 2% maximum drop probability
• TCP Red Range: 15% to 50% - 3% maximum drop probability
• Non-TCP traffic: 50 to 98% - 25% maximum drop probability
console(config-if-Te2/0/1)#random-detect queue-parms 0 min-thresh 5 10 15 50
max-thresh 15 25 50 98 drop-prob-scale 1 2 3 25
QoS Commands
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