Chapter 19
| 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
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, Port Channel)
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
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
