Dell PowerEdge VRTX - Manual (Page 427)

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FILE LOCATION: C:\Users\gina\Desktop\Checkout_new\Dell Plasma\User
Guide\Plasma_UGQoS.fm
D E L L CO N F I D E N T I A L – P R E L I MI N A RY 4/ 1 8 /1 3 - F O R PR O O F O N LY
The following is an example of the CLI command:
Queue
The switch supports four queues for each interface. Queue number four is the
highest priority queue. Queue number one is the lowest priority queue.
Traffic Limitation Methods
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 lowest-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). The type of WRR algorithm used in
the device is not the standard Deficit WRR (DWRR), but rather Shaped
Deficit WRR (SDWRR).
Combination of WRR and Strict Priority
The priority for handling traffic can be selected for each queue. When the
queuing mode is Weighted Round Robin for all queues, queues are serviced
according to their weights. If all queues are assigned strict priority, queues are
serviced according to that order.
The following is true if some queues are assigned strict priority and others are
assigned WRR:
• If one queue is assigned strict priority, all higher queues are also assigned
strict priority. Conversely, if a queue is assigned a WRR weight, all lower
queues must also have a WRR weight assigned to them.
• In the above case, traffic for the strict priority queues is always sent before
traffic from the WRR queues. Traffic from the WRR queues is forwarded
only after the strict priority queues have been emptied. The relative
portion from each WRR queue depends on its weight.
console(config)# interface gi0/8
console(config-if)# qos cos 3