Changing the Minimum Bandwidth Percentages of the WRR Queues

If you are using the weighted round robin mechanism instead of the strict priority mechanism, you can change the weights for each queue by changing the minimum percentage of bandwidth you want each queue to guarantee for its traffic.

By default, the eight QoS queues on RUCKUS ICX devices receive the minimum guaranteed percentages of a port’s total bandwidth, as shown in the following table. Note that the defaults differ when jumbo frames are enabled.

Table 1. Default Minimum Bandwidth Percentages on RUCKUS ICX Devices
QueueDefault Minimum Percentage of Bandwidth
Without Jumbo Frames With Jumbo Frames
qosp7 75% 44%
qosp6 7% 8%
qosp5 3% 8%
qosp4 3% 8%
qosp3 3% 8%
qosp2 3% 8%
qosp1 3% 8%
qosp0 3% 8%

When the queuing method is WRR, the software internally translates the percentages into weights. The weight associated with each queue controls how many packets are processed for the queue at a given stage of a cycle through the weighted round robin algorithm.

Note: Queue cycles on the FastIron devices are based on bytes. These devices service a given number of bytes (based on the weight) in each queue cycle.

The bandwidth allocated to each queue is based on the relative weights of the queues. You can change the bandwidth percentages allocated to the queues by changing the queue weights.

  1. Enter global configuration mode. 
    
device# configure terminal
  2. Change the bandwidth percentages for the queues. 
    
device(config)# qos profile qosp7 25 qosp6 15 qosp5 12 qosp4 12 qosp3 10 qosp2
10 qosp1 10 qosp0 6
Profile qosp7 : Priority7 bandwidth requested 25% calculated 25%
Profile qosp6 : Priority6 bandwidth requested 15% calculated 15%
Profile qosp5 : Priority5 bandwidth requested 12% calculated 12%
Profile qosp4 : Priority4 bandwidth requested 12% calculated 12%
Profile qosp3 : Priority3 bandwidth requested 10% calculated 10%
Profile qosp2 : Priority2 bandwidth requested 10% calculated 10%
Profile qosp1 : Priority1 bandwidth requested 10% calculated 10%
Profile qosp0 : Priority0 bandwidth requested 6% calculated 6%
    The assigned bandwidths must total 100%. The configuration is immediately verified by the command output.

    There is no minimum bandwidth requirement for a given queue.

    Note: FastIron devices do not adjust the bandwidth percentages you enter.
  3. Return to privileged EXEC mode. 
    
device(config)# exit
  4. Save the configuration. 
    
device# write memory

Change the Minimum Bandwidth Percentages of the WRR Queues Example


device# configure terminal
device(config)# qos profile qosp7 25 qosp6 15 qosp5 12 qosp4 12 qosp3 10 qosp2
10 qosp1 10 qosp0 6
device(config)# exit
device# write memory