Panasonic GA-ML Series Manual page 201

Parameter
Scheduler Method
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Choose the scheduler method, which is applied to the
port specified. The options available are as follows.
• Strict-Priority (SP) - This uses the strict-priority
scheduling on all the queues. This is a strict-priority
access that executes queues; the range is from the
highest CoS queue to the lowest queue.
• Round Robin (RR) - All the queues use and need a
round robin scheduling. This is the fair access, which
allows you to move to the next queue after providing
one packet with services on each queue.
• Weighted Round Robin (WRR) - This operates by
transmitting permitted packets to the transmission
queue in a sequential order of the round robin. At
the beginning, each queue sets the weight to a
configurable weighting. Every time packets coming
from CoS queues with a higher priority are
transmitted, the corresponding weights is subtracted
by one. Then, the packets in the lower CoS queues
receive services. If the weight of CoS queues reaches
zero (0), the queue services stop until the queue is
replenished. If the weight of all the CoS queues
reaches 0, it becomes replenished at the time. This is
the default option.
• Weight Deficit Round Robin (WDRR) - Service are
provided to the unprocessed credit, which is
accumulated on the transmission-queue, in a
sequential order of the round robin. At the
beginning, each queue sets a credit counter to the
value of configurable quantum.
• Every time packets are transmitted from the CoS
queue, the service right is provided to the next lower
CoS queue.
• If the value of a credit counter is less than 0, queue
services stop before the credit is replenished. If the
credit counter of all the CoS queues reaches 0, then
it is replenished. The credit counter becomes 0 or
minus, and then services are provided to all the
packets before transmitting the last packet
completely. If this occurs, the credit is replenished.
• After that, the credit quantum is added to a credit
counter of each CoS queue. The quantum of each
CoS queue may differ depending on a user
configuration. To set the specific CoS queue to the
SP mode, all the CoS queues whose priorities are
higher than it must be the strict-priority mode.
7 QoS (Quality of Service)
7.1.2 Port Scheduler Method
Overview
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