LARTC - May 2003 - How to be decided default burst , cburst value ?

Hi.

I know that quantum value is decided by rate/r2q.

but, I don't know how to be decided burst, cburst value.

How to be decided default burst and cburst value?

You should use the following formula. I did some
tests and it works.

  for rate 30Mbit/s use burst/cburst = 18k.
  Use that as a starting point. For other rate just
calculate the ratio and it hould give you the most
accurate values. 

   Example: Rate 15Mbit/s use 9k ( 30/15 = 2 --> 18/2
= 9).

   All the best.

--- openings <openings@palgong.knu.ac.kr> wrote:
> Hi.
> 
> I know that quantum value is decided by rate/r2q.
> 
> but, I don''t know how to be decided burst, cburst
> value.
> 
> How to be decided default burst and cburst value?
> 
> ,S
>
f)+-L)Y=jyaffvZ_j)fjb?psLmr


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On Monday 19 May 2003 05:16, openings wrote:
> Hi.
>
> I know that quantum value is decided by rate/r2q.
>
> but, I don''t know how to be decided burst, cburst value.
>
> How to be decided default burst and cburst value?
If you don''t specify the burst/cburst on the command line, htb will
calculate
the minimum bandwidth for you.  You can always a bigger value if you want a 
bigger burst/cburst.

From the tc source :

/* compute minimal allowed burst from rate; mtu is added here to make
 sure that buffer is larger than mtu and to have some safeguard space */
if (!buffer) buffer = opt.rate.rate / HZ + mtu;
if (!cbuffer) cbuffer = opt.ceil.rate / HZ + mtu;

So it also depends on your timer resolution (Hz).  The higher the resolution, 
the lower the burst can be.  

Stef

-- 

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

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