Class of Service Configuration
3-101
Web – Click Priority, Traffic Classes. Mark an interface and click Select to display
the current mapping of CoS values to output queues. Assign priorities to the traffic
classes (i.e., output queues) for the selected interface, then click Apply.
CLI – The following example shows how to change the CoS assignments to a
one-to-one mapping.
* Mapping specific values for CoS priorities is implemented as an interface configuration
command, but any changes will apply to the all interfaces on the switch.
Selecting the Queue Mode
You can set the switch to service the queues based on a strict rule that requires all
traffic in a higher priority queue to be processed before lower priority queues are
serviced, or use Weighted Round-Robin (WRR) queuing that specifies a relative
weight of each queue. WRR uses a predefined relative weight for each queue that
determines the percentage of service time the switch services each queue before
moving on to the next queue. This prevents the head-of-line blocking that can occur
with strict priority queuing.
Command Attributes
• WRR – Weighted Round-Robin shares bandwidth at the egress ports by using
scheduling weights 1, 4, 16, and 64 for queues 0 through 3 respectively.
(This is the default selection.)
• Strict – Services the egress queues in sequential order, transmitting all traffic
in the higher priority queues before servicing lower priority queues.
Web – Click Priority, Queue Mode. Select Strict or Wrr, then click Apply.
Console(config)#interface ethernet 1/1 4-84
Console(config)#queue cos-map 0 0 4-150
Console(config)#queue cos-map 1 1
Console(config)#queue cos-map 2 2
Console(config)#exit
Console#show queue cos-map ethernet 1/1 4-151
Information of Eth 1/1
Traffic Class : 0 1 2 3 4 5 6 7
Priority Queue: 0 1 2 1 2 2 3 3
