[LARTC] above rate and below rate HTB packet dequeuing

[Martin A. Brown]

Hello all,

I have a question about the details of HTB packet dequeuing and the effect
on scheduling of packets queued in different classes.  I have been unable
to answer this question with certainty either by reading the HTB user
guide [1] or the LARTC FAQ on docum.org [2].

The closest I can come to guessing the answer is the section on burst in
the HTB user guide [3].

Here's my question:

  When a sending class is below rate, how many bytes is the class allowed
  to transmit before another class is serviced?

It seems clear to me from this answer [4] in the LARTC FAQ, that the
quantum is used to allow each class to borrow from a parent in a turn.  Is
the class also allowed to dequeue only quantum bytes per turn (when above
rate but below ceil)?

But, more importantly, when a class is below rate, is it allowed to
dequeue a maximum of burst packets per turn?

Is this statement, then, accurate?

  - below rate, a class can dequeue up to burst bytes per turn
  - above rate, a class can dequeue up to quantum bytes per turn

Thanks for any replies,

-Martin

 [1] http://luxik.cdi.cz/~devik/qos/htb/manual/userg.htm
 [2] http://www.docum.org/stef.coene/qos/faq/cache/
 [3] http://luxik.cdi.cz/~devik/qos/htb/manual/userg.htm#burst
 [4] http://www.docum.org/stef.coene/qos/faq/cache/31.html


P.S. Groeten, Stef!

-- 
Martin A. Brown --- SecurePipe, Inc. --- mabrown@securepipe.com