Users Guide

Layer 2 Switching Commands 721
Explicit Congestion Notification (ECN):
ECN capability is an end-to-end feedback mechanism. Both ends of the TCP
connection must participate. When ECN is enabled, packets marked as ECN
capable and selected for discard by WRED are marked CE and are not
dropped. In cases of extreme congestion, ECN capable packets may be
dropped.
Use the show interfaces traffic command to see color aware drops and
congestion levels.
ECN capability can be enabled in Windows Server 2008 and later releases
using the following command:
netsh interface tcp set global ecncapability=enabled
N1500 Series Switches
N1500 Series switches only support a simple RED capability. The N1500
Series switch does not support configuration of the maximum threshold nor
can the threshold or drop probability be configured for non-TCP traffic.
Dell EMC Networking N1500 Series switches implements a simple Random
Early Discard (RED) capability. Only the minimum threshold (min-thresh)
and drop probability (drop-prob-scale) may be configured for the TCP colors
green/yellow/red. The maximum threshold may not be configured nor can the
threshold or drop probability be configured for non-TCP traffic. ECN
capability is supported.
Simple RED may be enabled/disabled for any CoS queue on the Dell EMC
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