Configuration Guide User guide

1990 FastIron Configuration Guide
53-1002494-02
Scheduling QoS information
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. FES and BI/FI queue cycles are based on packets.
The bytes-based scheme is more accurate than a packets-based scheme if packets vary greatly in
size.
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.
There is no minimum bandwidth requirement for a given queue. For example, queue qosp3 is not
required to have at least 50 percent of the bandwidth.
To change the bandwidth percentages for the queues, enter commands such as the following.
Note that this example uses the default queue names.
Syntax: [no] qos profile <queue> <percentage> <queue> <percentage> <queue> <percentage>
<queue> <percentage> <queue> <percentage> <queue> <percentage> <queue>
<percentage> <queue> <percentage>
Each <queue> variable specifies the name of a queue. You can specify the queues in any order on
the command line, but you must specify each queue.
The <percentage> variable specifies a number for the percentage of the device outbound
bandwidth that is allocated to the queue. Brocade QoS queues require a minimum bandwidth
percentage of 3 percent for each priority. When jumbo frames are enabled, the minimum
bandwidth requirement is 8 percent. If these minimum values are not met, QoS may not be
accurate.
Configuration notes for changing the bandwidth
• The total of the percentages you enter must equal 100.
• FastIron devices do not adjust the bandwidth percentages you enter. BigIron QoS does adjust
the bandwidth percentages to ensure that each queue has at least its required minimum
bandwidth percentage.
On FWS, FCX, and ICX devices, you can use QoS queue 1 for priority traffic, even when sFlow is
enabled on the port. This differs from the FastIron X Series devices, which support seven priorities
for user data instead of eight when sFlow is enabled. QoS queue 1 is reserved for sFlow and not
used by other packets. Any non-sFlow packets assigned to QoS queue 1 will be directed to QoS
queue 0. Note that the ICX 6430 does not support sFlow.
Brocade(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%