Hello,
Thank you for your replies. Let me summarize your opinions....
Let's assume I have 512 kbit/s synchronous link to my upstream provider.
I have two customers named "B" and "C". I want to be sure that they get at
last 8kbit/s. I want to limit maximum traffic generated per each customer
to 128 kbit/s.
A tree that follows describes what I did.
A
/ \
B C
Class A rate and ceiling is set to something like 490kbit/sek (or lower)
to move queues to my linux traffic shaper. I set equal prios, rate for B
and C equals 8 kbit/s, ceiling for B and C equals 128 kbit/s. This setup
is supposed to fulfill my needs. It should work as expected, right?
Now I try to improve my setup. What I require is to divide customer B and
C traffic into 3 classes - interactive(D,G) , www (E,H) and other
(F,I)respectively. I dont want to allow customer B or C traffic to go over
128kbit/s.I expanded last tree and created following tree.
A
/ \
B C
/|\ /|\
D E F G H I
D,G rate=4/ceil=64
E,H rate=3/ceil=128
F,I rate=1/ceil=32
Priorities for all classes are the same.
Lets assume all classes try to send at their maximum speed trying to
saturate the link. According to what you have written class D will get
64kbit/s, class E 128kbit/s and class F will get 32kbit/s. The sum is
224kbit/s if I am correct. Am I right?
I dont want it to happen since customers have paid for 128kbit/s with
guaranteed rato of 8kbit/s. Is there a way to acomplish my task???. Can it
be done using HTB only?
>> >Remaining bandwidth inside class B is distributed first to class D,
>> then E and then F and is limited by ceiling parameter . Right???
>> yes, what you have said is right.
> Confirmed. Lowest prio classes are allowed to send first.
It is intuitive. Thanks for confirmation. Anyway, classes D,E,F are
limited only by their ceil, not by ceil of class B. Hm?. Performance
reasons, right?
>> >Class A has available bandwidth. Rules for guaranteed rates for
>> classes D,E,F,G,H,I are fulfilled. So available bandwidth has to
>> >be distributed between class B and C equaly (assuming B and C has the
>> same rate and prio). Is remaining bandwidth distributed to classes D
>> and G, and then to classes E and H and at the end to classes F and
>> I???
> Yes.
It is also rather intuitive.
>
>> I remember having read something about the "rate" parameter of a
>> parent HTB class. I think it was that the "rate" parameter isn't
>> used, only the "ceil" parameter (of a parent HTB class) is important.
>> Check the list archive and the HTB home page because I'm not sure.
> Nor the rate, nor the ceil are respected if the child class can send.
> So if B end C can send the remaining bandwidth, they will. Even if the
> parent ceil is not permitting it.
Well... I hoped for opposite. If the ceiling of parent class is not
respected, then setting htb up the way I require is rather impossible.?
Right:( ?
>
>> If what I have written is true, there is a possibility that
>> bandwidth
>> is not distributed equally between classes B and C.
> Indeed. This can be true IF class B and C have different rates. But I
> did some tests and it seems to be that remaining bandwidth is splitted
> 50-50 and according to the rates. Strange. I will test it further
> tomorrow. But the prio of the parent is respected. So the parent with
> the lowest prio get all remaining bandwidth.
I would like to see the results, if you were so kind...
>
>> >What if C and B have different rates?
>> >
>> >Is prio parameter taken into account when htb tries to meet
>> guaranteed rate rules?
>>
>> I think the "prio" parameter is only used after all classes have
>> reached their guaranteed minimum rate, to allow the user to create
>> classes that will borrow bandwidth over other classes.
> Yep.
OK. You have cleared thing up:)
>
>> >What happens when sum of guaranteed rates of children class is bigger
>> than guaranteed rate of parent (rate parameter is overbooked) and all
>> of classes are requesting maximum bandwidth? Are classes with lower
>> prio given bandwidth first?
>>
>> There are rules that you should respect when creating classes.
>> Check the FAQ on the HTB home site.
> And I have some more on the faq page on www.docum.org
This FAQ is a nice piece of work Stef:) Well done:)
>
>> >Are packets classfied to class D and G sent first?
>>
>> No, unless classes D and G haven't reached their guaranteed minimum
>> rate.
>>
>> >What will happen if prio of class B is 0 and class C is 3? I assume
>> remaining bandwidth is first distributed to class B and to its
>> children. Right???
>>
>> Same answer regarding parent HTB classes. I'm not sure.
> All remaining bandwidth goes to B.
It goes to B and then to its children, right? I mean, there are no
classifiers (filters) pointing to class B directly, only to its children.
Robert Kryczało
