Allied Telesis AlliedWare Plus User Manual
Page 25
Page 25 | AlliedWare Plus™ OS: Overview of QoS
These fundamental curves are collected into RED curve groups. A group is a collection of
three curves, one for each of the three possible bandwidth classes, as shown in the following
figure.
Additionally, one other parameter is defined on each RED curve group. This parameter is the
averaging factor. The averaging factor influences how the queue length is calculated. If the
averaging factor is 0, then the queue length value that the shaper uses in its calculation of
whether a certain packet should be dropped is the exact current length of the queue. But, if
you increase the averaging factor, then the shaper starts calculating an average length of the
queue over a certain time period, and uses this averaged value in its “should-I-drop-the-
packet” calculation.
Applying
RED curves
to ports
To apply a set of RED curves to the egress queues on a given port, use the commands:
awplus(config)#interface <interface-name>
awplus(config-if)#mls qos queue-set <1-4> random-detect
If you enter this command without configuring the RED curve settings (see
), the switch uses the default queue set values. These are described
in
.
Configuring
RED curve
settings
RED curve groups are defined in queue sets, so you can have up 4 different sets of RED
behaviour on the switch.
The commands for configuring the queue sets start with:
awplus(config)#mls qos queue-set <1-4> ...
After this, you can use the command to configure the averaging factor, the thresholds and the
drop probability. You can configure the queue-set parameters for all 8 egress queues, or for
any subset of the egress queues. Configuring a subset lets you configure different queue
shaping settings for different queues on a port.
Drop
Probability
%
100%
0%
Start 3
Start 3
Stop 3
Stop 3
Drop 3
Drop 3
Drop 2
Drop 2
Drop 1
Drop 1
Start 2
Start 2
Stop 2
Stop 2
Start 1
Start 1
Stop 1
Stop 1
Queue Length (bytes)
MAX queue length
MAX queue length
BW
Class 3
BW
Class 2
BW
Class 1
QoS3.eps