[LARTC] total bandwidth ocupied

[LARTC] total bandwidth ocupied

[Adi Nugroho]

Dear sir/madam,

I discover that bandwidth usage which is limited using htb is about 5 to 10% 
higher than the rate/ceil we set, if we monitor it using iptraf.

I become more confused since I saw, the grafic in HTB homepage are also show 
more bandwidth than the setting.

My question is:
* what is the exac value of this over bandwidth?
* how to make the bandwidth are limited exacly at "x" kbps?

-- 
Regards,

Adi Nugroho
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Re: [LARTC] total bandwidth ocupied

[Stef Coene]

On Monday 16 December 2002 03:25, Adi Nugroho wrote:
> Dear sir/madam,
>
> I discover that bandwidth usage which is limited using htb is about 5 to
> 10% higher than the rate/ceil we set, if we monitor it using iptraf.
>
> I become more confused since I saw, the grafic in HTB homepage are also
> show more bandwidth than the setting.
>
> My question is:
> * what is the exac value of this over bandwidth?
> * how to make the bandwidth are limited exacly at "x" kbps?
I did some "stream" tests with htb.  I generated a lot of tcp traffic with tcp 
and recorded the shaped bandwidth.  The result is allmost perfect. (results 
can be found on www.docum.org on the test pages).

But in a real world scenario, you also have bursts in the traffic.  Maybe you 
allow bursts (you always have some minimal bursts) so the average bandwidth 
may be higher then the configured bandwith.  

Stef


-- 

stef.coene@docum.org
 "Using Linux as bandwidth manager"
     http://www.docum.org/
     #lartc @ irc.oftc.net

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Re: [LARTC] total bandwidth ocupied

[Catalin Bucur]

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Adi Nugroho wrote:
| Dear sir/madam,
|
| I discover that bandwidth usage which is limited using htb is about 5
to 10%
| higher than the rate/ceil we set, if we monitor it using iptraf.
|
| I become more confused since I saw, the grafic in HTB homepage are
also show
| more bandwidth than the setting.
|
| My question is:
| * what is the exac value of this over bandwidth?

It depends of burst and cburst values that you (or tc) set. In Devik's
user guide says: "Latest tc tool will compute and set the smallest
possible burst when it is not specified". This means:
minimal_burst=max_rate*timer_resolution
So, for 2Mbit bandwidth on i386, minimal_burst=2Mbit*10ms kbit. This
says the theory, but in real world I saw that this minimal_burst
calculated by tc could be up to 64kbit. Am I missing something?

| * how to make the bandwidth are limited exacly at "x" kbps?

Set a lower value for ceil and a value for cburst thus:
ceil+cburst=limited_bandwidth

- --
Catalin Bucur      mailto:cata@geniusnet.ro
NOC @ Genius Network SRL - Galati - Romania

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Re: [LARTC] total bandwidth ocupied

[Adi Nugroho]

Pada hari Selasa, 17 Desember 2002 01:06, Catalin Bucur menulis:
> | * how to make the bandwidth are limited exacly at "x" kbps?
>
> Set a lower value for ceil and a value for cburst thus:
> ceil+cburst=limited_bandwidth

Thank you very much.
This calculation is very helpfull.

-- 
Salam,

Adi Nugroho
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