Service Manual

You will also be able to mark both DSCP and Dot1p in the L3 Input Qos Policy:
Dell(conf)#qos-policy-input qos-input
Dell(conf-qos-policy-in)#set mac-dot1p 2
Dell(conf-qos-policy-in)#set ip-dscp 5
Dell Dell(conf-qos-policy-in)#
Weighted Random Early Detection
Weighted random early detection (WRED) is a congestion avoidance mechanism that drops packets to prevent buering resources from
being consumed.
The WRED congestion avoidance mechanism drops packets to prevent buering resources from being consumed.
Trac is a mixture of various kinds of packets. The rate at which some types of packets arrive might be greater than others. In this case,
the space on the buer and trac manager (BTM) (ingress or egress) can be consumed by only one or a few types of trac, leaving no
space for other types. You can apply a WRED prole to a policy-map so that specied trac can be prevented from consuming too much
of the BTM resources.
WRED uses a prole to specify minimum and maximum threshold values. The minimum threshold is the allotted buer space for specied
trac, for example, 1000KB on egress. If the 1000KB is consumed, packets are dropped randomly at an exponential rate until the maximum
threshold is reached (as shown in the following illustration); this procedure is the “early detection” part of WRED. If the maximum threshold,
for example, 2000KB, is reached, all incoming packets are dropped until the buer space consumes less than 2000KB of the specied
trac.
Quality of Service (QoS) 665