Edge-Core ECS4810-12M Layer 2, Management Manual

Page: 974 / 1236

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HAPTER
37
| 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.
S
YNTAX
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 - Strict priority is used for the high-priority queues and
WRR for the rest of the queues.
queue-type-list - Indicates if the queue is a normal or strict type.
(Options: 0 indicates a normal queue, 1 indicates a strict queue)
D
EFAULT
S
ETTING
WRR
C
OMMAND
M
ODE
Global Configuration
C
OMMAND
U
SAGE
◆
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 service is
used for the high priority queues and weighted service for the
remaining queues. The queues assigned to use strict priority should be
specified using the Strict Mode field 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.