Configuration Guide User guide

1988 FastIron Configuration Guide
53-1002494-02
Scheduling QoS information
By default, when you select the combined SP and WRR queueing method, the Brocade device
assigns strict priority to traffic in qosp7 and qosp6, and weighted round robin priority to traffic
in qosp0 through qosp5. Thus, the Brocade device schedules traffic in queue 7 and queue 6
first, based on the strict priority queueing method. When there is no traffic in queue 7 and
queue 6, the device schedules the other queues in round-robin fashion from the highest
priority queue to the lowest priority queue.
NOTE
Brocade stackable devices that are operating as members of a stack reserve queue 7 for
stacking functions. For more information, refer to “QoS for Brocade stackable devices” on
page 1970.
By default, when you specify the combined SP and WRR queuing method, the system balances
the traffic among the queues as shown in Table 346. If desired, you can change the default
bandwidth values as shown in “Bandwidth allocations of the hybrid WRR and SP queues” on
page 1991.
Selecting the QoS queuing method
By default, Brocade devices use the WRR method of packet prioritization. To change the method to
SP, enter the qos mechanism strict command at the global CONFIG level of the CLI.
Brocade(config)#qos mechanism strict
To change the method back to WRR, enter the qos mechanism weighted command.
Brocade(config)#qos mechanism weighted
Syntax: [no] qos mechanism strict | weighted
To change the queuing mechanism to the combined SP and WRR method, enter the qos
mechanism mixed-sp-wrr command at the global CONFIG level of the CLI.
Brocade(config)#qos mechanism mixed-sp-wrr
Syntax: qos mechanism mixed-sp-wrr
TABLE 346 Default bandwidth for combined SP and WRR queueing methods
Queue Default bandwidth
qosp7 Strict Priority (highest priority)
qosp6 Strict Priority
qosp5 25%
qosp4 15%
qosp3 15%
qosp2 15%
qosp1 15%
qosp0 15% (lowest priority)