Queue Shaping-Queue Sets, Red, And Tail-Drop - Allied Telesis AlliedWare Plus Overview

Queue shaping—queue sets, RED, and tail-drop
A queue set defines how the switch determines what traffic to drop when a port's queues
become congested. The queue set applies to one or more of the port's queues, and specifies
the queue size thresholds at which the port starts to drop traffic from that queue.
You can use up to four different queue sets across the switch.There are two steps involved in
configuring queue sets:
1.
2.
There are two options for how each queue set drops excess traffic:
In random-detect mode, the switch uses RED to shape queues. In tail-drop mode, the switch
simply drops excess traffic from the end of queues. Both modes are color-aware—you can
configure different thresholds for different bandwidth classes.
The following sections describe how to configure random-detect and tail-drop mode, but
first you need to consider the default settings.
Default If you do not configure queue shaping:
settings
Don't customise the default queue sets unless you want to change the settings on
all ports of that type.
You can check which are the default queue sets and their current settings, by using the
command:
The following table shows the values for the default queue set for each port speed. These
settings apply to each egress queue and each bandwidth class—green, yellow and red traffic
all have the same values. The unused queue sets are empty, so all their values are 0.
Port speed
1G
Page 23 | AlliedWare Plus™ OS: Overview of QoS
configure the queue set parameters
apply the queue set to the desired port
random-detect mode
tail-drop mode
10/100/1000M ports use tail-drop mode with settings from queue set 1 (which gets a
default description of "1G Defaults")
10G ports use tail-drop mode with settings from queue set 2 if there are also 1G ports
present, or otherwise settings from queue set 1 (the used queue set gets a default
description of "10G Defaults")
awplus#show mls qos queue-set
Setting
Minimum threshold
Maximum threshold
Drop probability
Averaging factor
Value
100 KB
125 KB
50%
9