xStack DGS-3600 Series Layer 3 Gigabit Ethernet Managed Switch CLI Manual
111
Port RX Rate (64Kbit/sec) TX_Rate (64Kbit/sec)
---- ------------------------ ----------------------
1 no_limit 10
2 no_limit 10
3 no_limit 10
4 no_limit 10
5 no_limit 10
6 no_limit 10
7 no_limit 10
8 no_limit 10
9 no_limit 10
10 no_limit 10
DGS-3627:5#
config scheduling
Purpose
Used to configure the traffic scheduling mechanism for each COS queue.
Syntax
config scheduling <class_id 0-6> {max_packet <value 0-15>}
Description
The Switch contains seven hardware priority queues. Incoming packets must be
mapped to one of these seven queues. This command is used to specify the
rotation by which these eight hardware priority queues are emptied. The Switch’s
default (if the
config scheduling
command is not used, or if the config scheduling
command is entered with the
max_packet
set to 0) is to empty the hardware priority
queues in order
−
from the highest priority queue (hardware queue 6) to the lowest
priority queue (hardware queue 0). Each hardware queue will transmit all of the
packets in its buffer before allowing the next lower priority queue to transmit its
packets. When the lowest hardware priority queue has finished transmitting all of its
packets, the highest hardware priority queue can again transmit any packets it may
have received.
The
max_packets
parameter allows users to specify the maximum number of
packets a given hardware priority queue can transmit before allowing the next
lowest hardware priority queue to begin transmitting its packets. A value between 0
and 15 can be specified. For example, if a value of 3 is specified, then the highest
hardware priority queue (queue 6) will be allowed to transmit three packets
−
then
the next lowest hardware priority queue (number 5) will be allowed to transmit three
packets, and so on, until all of the queues have transmitted three packets. The
process will then repeat.
Entering a
0
into the
<value 0-15>
field of the
max_packet
parameter allows for the
creation of a Combination Queue for the forwarding of packets. This Combination
Queue allows for a combination of strict and weight-fair (weighted round-robin
“
WRR
”
) scheduling. Priority classes that have a
0
in the
max_packet
field will
forward packets with strict priority scheduling. The remaining classes, that do not
have a
0
in their
max_packet
field, will follow a weighted round-robin (WRR)
method of forwarding packets — as long as the priority classes with a
0
in their
max_packet
field are empty. When a packet arrives in a priority class with a
0
in its
max_packet
field, this class will automatically begin forwarding packets until it is
empty. Once a priority class with a
0
in its
max_packet
field is empty, the remaining
priority classes will reset the weighted round-robin (WRR) cycle of forwarding
packets, starting with the highest available priority class. Priority classes with an
equal level of priority and equal entries in their
max_packet
field will empty their
fields based on hardware priority scheduling.
Parameters
<class_id 0-6>
−
This specifies to which of the seven hardware priority queues the
config scheduling
command will apply. The seven hardware priority queues are
identified by number, from
0
to
6
, with the
0
queue being the lowest priority.
max_packet <value 0-15>
−
Specifies the maximum number of packets the above
specified hardware priority queue will be allowed to transmit before allowing the
next lowest priority queue to transmit its packets. A value between
0
and
15
can be
specified.
