D-Link DGS-3612G - xStack Switch Reference Manual page 319

The following values may be assigned to the QoS classes to set the scheduling.
Parameter Description
Select the unit to configure.
Unit
A consecutive group of ports may be configured starting with the selected port.
From/To
Class ID Select the class ID from Class-0 through Class-6.
Max. Packet (0- Specify the maximum number of packets the above specified hardware priority class of service
will be allowed to transmit before allowing the next lowest priority queue to transmit its packets.
15)
A value between 0 and 15 can be specified.
Click Apply to implement changes made.
Configuring the Combination Queue
Utilizing the QoS Output Scheduling Settings window shown above, the Switch 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 for emptying given classes of service. To set the combination queue, enter a 0 for the Max Packets entry of the
corresponding priority classes of service listed in the window above. Priority classes of service that have a 0 in the Max Packet
field will forward packets with strict priority scheduling. The remaining classes of service, 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 classes of service
with a 0 in their Max Packet field are empty. When a packet arrives in a priority class with a 0 in its Max Packet field, this class of
service will automatically begin forwarding packets until it is empty. Once a priority class of service with a 0 in its Max Packet
field is empty, the remaining priority classes of service will reset the weighted round-robin (WRR) cycle of forwarding packets,
starting with the highest available priority class of service. Priority classes of service 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
®
xStack DGS-3600 Series Layer 3 Managed Gigabit Ethernet Switch
Figure 5- 7. QoS Output Scheduling Settings window
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