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Introduction to DRO-250i
Packets are scheduled from the head of a given queue only if all queues of
higher priority are empty. Within each of the priority queues, packets are
scheduled in FIFO order.
The PRIO qdisc is a classic queuing discipline that contains an arbitrary
number of classes of different priority. When user creates a new PRIO
queue pfifo sub-queuing disciplines are created depending on number of
bands user is giving. <Bands> number of classes named m:1, m:2 and m:3
etc are created where m is the major number of the queuing discipline &
1,2,3..are minor numbers. Each of these classes are assembled with a pfifo
as its own qdisc.
Bands:
The bands are classes, and are called major:1 to major:3 by default, so if
your PRIO qdisc is called 12:, tc filter traffic to 12:1 (band 0) to grant it
more priority. Reiterating, band 0 goes to minor number 1, band 1 to
minor number 2, etc.
Handle:
Queues are identified by a handle <major number, minor number>, where
the minor number is zero for queues. Handles are used to associate classes
or sub-queues to queuing disciplines.
Parent:
Parent does not apply for root qdisc. Major number represents the parent
of the sub-queue or child queue. This will be equal to the handle major
number of parent queue. Minor number represents the band number of the
sub queue.
Token Bucket Filter (TBF):
Token Bucket Filter is a classless qdisc. It is a simple queue that only
passes packets arriving at a rate which is not exceeding some
administratively set rate, with the possibility to allow short bursts in
excess of his rate. The TBF implementation consists of a buffer (bucket)
DRO-250i User Manual
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