Quality of Service (QoS)
©2008 Allied Telesis Inc. All rights reserved.
39.24
AlliedWare Plus
TM
Operating System Software Reference C613-50003-00 REV E
Software Version 5.2.1
Drop Mode
The drop mode sets the limits for packets in the eight egress queues and determines how
packets will be dropped if the queues become congested. Two drop methods may be
employed, these are:
■
Tail Drop
■
Weighted Random Early Discard (WRED)
For both the above methods there are 4 pre-existing queue-sets numbered 1-4. You can
configure each queue-set with a separate drop mode profile for each of the 8 egress queues.
Your switch has 4 pre-existing queue-sets, one pre-configured for 1G ports and another for
10 G ports. These configurations are shown in
Figure 39-10
and
Figure 39-11
. You can name
and reconfigure these profiles and change the association of queue sets to switch ports. These
steps are explained later in this section.
Note:
The default drop mode operation is
Tail Drop.
In this situation the value set by the
mls
qos queue-set drop-probability
command is ignored, and a drop value of 0 (i.e 100%) is
internally applied. Also the value set for the
minimum threshold
is ignored, and the
averaging factor
is replaced by an instantaneous comparison of queue size with the
maximum threshold
figure
(
Max
th
).