CLI Reference Guide-R07

Chapter 21 | Class of Service Commands
Priority Commands (Layer 2)
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queue mode This command sets the scheduling mode used for processing each of the class of
service (CoS) priority queues. The options include strict priority, Weighted Round-
Robin (WRR), or a combination of strict and weighted queuing. Use the no form to
restore the default value.
Syntax
queue mode {strict | wrr | strict-wrr [queue-type-list]}
no queue mode
strict - Services the egress queues in sequential order, transmitting all
traffic in the higher priority queues before servicing lower priority queues.
This ensures that the highest priority packets are always serviced first,
ahead of all other traffic.
wrr - Weighted Round-Robin shares bandwidth at the egress ports by using
scheduling weights (based on the queue weight command), and servicing
each queue in a round-robin fashion.
strict-wrr - Uses strict or weighted service as specified for each queue.
queue-type-list - Indicates if the queue is a normal or strict type.
(Options: 0 indicates a normal queue, 1 indicates a strict queue)
Default Setting
WRR
Command Mode
Interface Configuration (Ethernet)
Command Usage
◆ The switch can be set to service the port queues based on strict priority, WRR,
or a combination of strict and weighted queueing.
◆ Strict priority requires all traffic in a higher priority queue to be processed
before lower priority queues are serviced.
◆ Weighted Round Robin (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. Use the queue weight command to
assign weights for WRR queuing to the eight priority queues.
◆ If Strict and WRR mode is selected, a combination of strict and weighted service
is used as specified for each queue. The queues assigned to use strict or WRR
priority should be specified using the queue-type-list parameter.
◆ A weight can be assigned to each of the weighted queues (and thereby to the
corresponding traffic priorities). This weight sets the frequency at which each
queue is polled for service, and subsequently affects the response time for
software applications assigned a specific priority value.