Re: [LARTC] Fair bandwidth oversubscribing ? How with HTB ?

[Patrick McHardy <kaber@trash.net>]

Santiago J. Ruano Rincón wrote:

>try HFSC, Hierarchical Fair Service Curve:
>
>http://trash.net/~kaber/hfsc
>http://www-2.cs.cmu.edu/~hzhang/HFSC/
>
>i'm going to test it in this week.
>  
>

This should indeed work with HFSC if the custumer-classes have only
links-haring service curves and no realtime service curves. The parent
class would be limited with an upper-limit service curve. With
link-sharing service curves, only the relative differences of virtual
time on a level of the heirarchy are relevant, so there is no problem
oversubscribing the parent class. the upper-limit service curve of the
parent limits the total bandwidth, unlike the link-sharing curve it
uses wall-clock time.

Best regards,
Patrick

PS: Please let me know if you are successful.


>Quoting Simon Byrnand <simon@igrin.co.nz>:
>
>  
>
>>Hopefully someone has a suggestion on how I might do this...as I can't
>>figure it out :(
>>
>>I need to be able to set up a group of seperate users who have a
>>"bandwidth pool" they share, but also be able to limit their individual
>>bandwidth as well.
>>
>>Example:
>>
>>I have 5 customers and would like to be able to provide them with a
>>maximum of 256Kbit each, with a CIR of 33%.
>>
>>To do this, I'd like the 5 customers to share a parent group which is
>>therefore limited to 426Kbit, Which is 5*256Kbit/3.
>>
>>The idea being that individual customers can achieve up to a maximum of
>>256Kbit provided that the total group pool doesn't exceed 426Kbit, and if
>>the total group pool maxes out, then each customer should get reduced
>>bandwidth in fair ratios based on their individual maximum setting.
>>(Currently 256Kbit for all of them, but I'd like to be able to
>>differentiate them later)
>>
>>If all 5 were trying to fully utilize their bandwidth at the same time,
>>they should get a fairly distributed 33% of their maximum - eg about
>>85Kbit.
>>
>>The problem I can see is that both CBQ and HTB don't seem to honour
>>situations where the sum of all the child rates exceeds the parent rate -
>>the parent rate is ignored so the 426Kbit cap is exceeded. The HTB docs
>>even explicitely say this won't work.
>>
>>So is there any tricky way to do this with slightly different semantics ?
>>Surely there must be some way :-) I've spent many long hours studying CBQ
>>and trying things out and finally came to the conclusion that CBQ alone
>>just can't do it, but I was hoping HTB could, but thus far I've been
>>unsuccessful here too..
>>
>>Currently I'm using CBQ but I'm limited in that the individual maximum
>>speeds can only equal the parent group maximum bandwidth which is workable
>>for a few customers, but not very satisfactory and not flexible enough as
>>I add more customers.
>>
>>If someone could point me in the right direction or just give me a firm
>>"nope, can't be done" that would be great....
>>
>>I'd also like to enable short term bursting over and above this as well,
>>to improve responsiveness during downloading, say, 33% overbandwidth for 5
>>seconds, that sort of thing, but I'll cross that bridge when (if) I get to
>>it...(any comments here on how effective enabling bursting is for reducing
>>the dreaded unresponsiveness-during-downloads problem would be welcome
>>too)
>>
>>Regards,
>>Simon
>>
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>>    
>>
>
>
>Santiago J. Ruano Rincón
>
>Avatar Ltda.
>ParqueSoft Popayán
>+57-2 8221214
>
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>  
>


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