DELL 8132 ユーザーズマニュアル

QoS Commands

Global Config mode, Interface Config mode (physical and port-channel), 

Interface Range mode

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.

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

2CSPC4.X8100-SWUM102.book  Page 677  Friday, March 15, 2013  8:56 AM