Configuring The Combination Queue - D-Link DXS-3326GSR Manual

You may assign the following values to the QoS classes to set the scheduling.
Parameter
Max. Packets
Click Apply to implement changes made.

Configuring the Combination Queue

Utilizing the QoS Output Scheduling Configuration window shown above, the DXS-3326GSR can implement a
combination queue for forwarding packets. This combination queue allows for a combination of strict and weight-fair
(weighted round-robin "WRR") scheduling. To set the combination queue, enter a 0 for the Max Packets entry of the
corresponding priority queues listed in the window above. Priority queues that have a 0 in the Max Packet field will
forward packets with strict priority scheduling. The remaining queues, that do not have a 0 in their Max Packet field, will
follow a weighted round-robin (WRR) method of forwarding packets — as long as the priority queues with a 0 in their Max
Packet field are empty. When a packet arrives in a priority queue with a 0 in its Max Packet field, this queue will
automatically begin forwarding packets until it is empty. Once a priority queue with a 0 in its Max Packet field is empty,
the remaining priority queues will reset the weighted round-robin (WRR) cycle of forwarding packets, starting with the
highest available priority queue. Priority queues with an equal level of priority and equal entries in their Max Packet field
will empty their fields based on hardware priority scheduling. The Max Packet parameter allows you to specify the
maximum number of packets a given priority queue can transmit per weighted round-robin (WRR) scheduling cycle. This
provides for a controllable CoS behavior while allowing other queues to empty as well. A value between 0 and 15 packets
can be specified per priority queue to create the combination queue.
The example window below displays an example of the combination queue where Class-1 will have a strict priority for
emptying its queue, while the other classes will follow a weight fair scheduling.
DXS-3326GSR Gigabit Layer 3 Switch
Figure 6- 43. QoS Output Scheduling Configuration window
Description
Specifies the maximum number of packets the above specified hardware priority
queue will be allowed to transmit before allowing the next lowest priority queue to
transmit its packets. A value between 0 and 15 can be specified.
NOTE: The settings you assign to the queues, numbers 0 to 7, represent
the IEEE 802.1p priority tag number. Do not confuse these settings with
port numbers.
NOTE: Entering a 0 for the Max Packets field in the QoS Ouput
Scheduling Configuration window above will create a Combination
Queue. For more information on implementation of this feature, see the
next section, Configuring the Combination Queue.
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