Configuring Qos Queues - Cisco Small Business 200 Series Administration Manual

Quality of Service
Configuring QoS - General
The list of ports/LAGs is displayed. QoS State displays whether QoS is enabled on the interface.
STEP 3
STEP 4
STEP 5
STEP 6

Configuring QoS Queues

There are two ways of determining how traffic in queues is handled, Strict Priority and Weighted Round
Robin (WRR).
• Strict Priority—Egress traffic from the highest-priority queue is transmitted first. Traffic from the
lower queues is processed only after the highest queue has been transmitted, thus providing the
highest level of priority of traffic to the highest numbered queue.
• Weighted Round Robin (WRR)—In WRR mode the number of packets sent from the queue is
proportional to the weight of the queue (the higher the weight the more frames are sent). For
example, if there are a maximum of four queues possible and all four queues are WRR and the default
weights are used, queue1 receives 1/15 of the bandwidth (assuming all queues are saturated and
there is congestion), queue 2 receives 2/15, queue 3 receives 4/15 and queue 4 receives 8 /15 of the
bandwidth. The type of WRR algorithm used in the device is not the standard Deficit WRR (DWRR),
but rather Shaped Deficit WRR (SDWRR).
The queuing modes can be selected in the Queue page. When the queuing mode is by strict priority, the
priority sets the order in which queues are serviced, starting with Queue 4 or Queue 8 (the highest priority
queue) and going to the next lower queue when each queue is completed.
When the queuing mode is Weighted Round Robin, queues are serviced until their quota has been used up
and then another queue is serviced.
It is also possible to assign some of the lower queues to WRR, while keeping some of the higher queues in
strict priority. In this case traffic for the strict priority queues is always sent before traffic from the WRR
queues. Only after the strict priority queues have been emptied is traffic from the WRR queues forwarded.
(The relative portion from each WRR queue depends on its weight).
To select the priority method and enter WRR data.
STEP 1
STEP 2
Cisco Small Business 200 Series Smart Switch Administration Guide
Select an interface, and click Edit.
Select the Port or LAG interface.
Click to enable or disable QoS State for this interface.
Click Apply. The Running Configuration file is updated.
Click Quality of Service > General > Queue.
Enter the parameters.
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