User`s guide

DES-3226S Layer 2 Switch CLI Reference
149
config scheduling
Purpose Used to configure traffic scheduling for each of
the switch’s QoS queues.
Syntax
config scheduling <class_id 0-3>
{max_packet <value 0-255>|max_latency
<value 0-255>}
Description The switch contains four hardware priority
queues per device. The switch’s default settings
draw down the four hardware queues in order,
from the highest priority (Class 3) to the lowest
priority (Class 0). Starting with the highest
priority queue (Class 3), the highest priority
queue will transmit all of the packets and empty
its buffer before allowing the next lower priority
queue to transmit its packets. The next highest
priority queue will empty before proceeding to
the next queue and so on. Lower priority queues
are allowed to transmit only if
the higher priority
queue(s) in the buffer are completely emptied.
Packets in the higher priority queues are always
emptied before any in the lower priority queues
regardless of latency or volume of the lower
priority queues.
The default settings for QoS scheduling employ
this strict priority scheme to empty priority
queues.
The config scheduling command can be used
to specify the round robin rotation by which
these four hardware priority queues are
reduced. To use a round-robin scheme, the
max_packets parameters and/or the
max_latency parameters must be changed from
the default value of 0.
The max_packets parameter allows you to
specify the maximum number of packets a given
priority queue can transmit before allowing the