QoS Commands
©2008 Allied Telesis Inc. All rights reserved.
Software Version 5.2.1
AlliedWare Plus
TM
Operating System Software Reference C613-50003-00 REV E
40.31
mls qos queue-set drop-probability
Sets the drop probability for each bandwidth-class. This probability is the likely hood that a
packet is dropped when the average queue length is between the minimum and maximum
threshold for that bandwidth class. Once the average queue length is above the maximum
threshold the probability jumps to 100%.
The queues parameter is optional and if not specified will default to setting the thresholds for all
queues. This parameter is only valid when a port is using this queue-set in random-detect
mode.
Syntax
mls qos queue-set <1-4> queues [0][1][2][3][4][5][6][7] drop-
probability <0-15> <0-15> <0-15>
The drop probability is 100% for a setting of 0 and halves for each integer value increase. The
following table shows probability values for drop values of 0 to 7. Default: 1.
Drop Probability
Mode
Configure Mode
Examples
To set the drop-probability for queues 1-3 in queue-set 2 to be 50%, use the command:
The drop-probability parameter specifies the maximum drop-probability for packets when
using the random-detect (RED) drop mode. This is the probability that a packet will be
dropped when the computed average queue length reaches the Max threshold value setting
for a specific traffic class within a specific queue.
The drop-probability is 100% for a drop value of 0, and halves with each increment. For
example, a drop1 value of 4 gives a drop probability of 1/16, or 6.25%. The default is 1.
Parameter
Description
mls
Multi-Layer Switch(L2/L3)
qos
Quality of Service
queue-set
queue-set
<1-4>
queue-set ID
[0] . . . [7]
List of queues to configure. Up to 8 queues (0-7) can be configured
within a particular queue set.
drop-probability
Configure maximum drop probability for each bandwidth-class.
See the following Drop Probability table.
<0-15>
Maximum drop-probability factor for green traffic
<0-15>
Maximum drop-probability factor for yellow traffic
<0-15>
Maximum drop-probability factor for red traffic
Drop Value
0
1
2
3
4
5
6
7
Drop Probability
100%
50%
25%
12.5% 6.25% 3.125
%
1.562
0.781
awplus#
config terminal
awplus(config)#
mls qos queue-set 2 queues 1 2 3 drop-
probability 1 1 1