Administrator Guide

Layer 2 Switching Commands 695
Simple RED may be enabled/disabled for any CoS queue on the Dell
Networking N1500 Series switches, however, the drop probability must be one
of the values given below. The percentage before the dash indicates the
actual drop probability. The number after the dash indicates the value
entered in the drop-prob-scale parameter.
0.097% - 1
0.195% - 2
0.391% - 4
0.781% - 8
1.563% - 16
3.125% - 31
6.250% - 63
100% - 100
Examples
Example 1
This example enables WRED on internal CoS 0 queue for unmarked packets
and set the green, yellow, and red colored traffic to utilize WRED starting at
3% of port congestion with a drop probability of 1%, 2% and 3%, respectively.
In this configuration, non-TCP traffic uses tail-drop queue discipline with a
drop threshold at 100% of the statically calculated port queue length vs. the
dynamically calculated value used by the normal tail-drop mechanism
(approx. 1/2 remaining free packet buffer memory).
console(config)# cos-queue random-detect 0
console(config)# random-detect queue-parms 0 min-thresh 3 3 3 100 max-thresh
10 10 10 100 drop-prob-scale 1 2 3 0
Example 2
This example configures simple RED on an N1500 series switch. CoS queue 1
is globally configured for simple RED with a congestion threshold of 50% and
a drop probability of 0.781% for green colored traffic.
console(config)# random-detect queue-parms 1 min-thresh 50 0 0 drop-prob-
scale 8 0 0
console(config)#cos-queue random-detect 1
2CSNXXX_SWUM204.book Page 695 Monday, January 25, 2016 1:25 PM