[Bridge] Limitation in virtual bridge number

[Bridge] Limitation in virtual bridge number

[Fermín Galán]

Hello,

I would like to know wether the number of
virtual bridges that can be created (with
'brctl addbr') is limited to a given number.

My question is due to certain tests that I have
performed, the number of virtual bridges cann't be
greater than 32. Triying to add the 33rd bridge
with 'brctl addbr' works, but causes the removal
of the oldest one (the first in the 'brctl show' list):
the number of existing virtual bridges is never
more than 32.

As reference, I have performed these tests in
a Linux 2.4.21 kernel, with bridge support compiled
as module (I can give you more information, if you
need it).

Where resides the limitation? In the virtual bridge
kernel support? In the brctl tool? In the way of
compiling? Maybe is a bug?

I would like to know how can I create more
than 32 virtual bridges (if possible).

Thank you very much for your attention!

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Fermín

Re: [Bridge] Limitation in virtual bridge number

[Bart De Schuymer]

On Saturday 27 March 2004 17:10, Fermín Galán wrote:
> I would like to know how can I create more
> than 32 virtual bridges (if possible).

The kernel actually creates any number of bridges. It turns out the userspace 
code only handles 32 bridges. It turns out that the kernel code that is 
executed for the show command only handles 64 bridges.

You can test this yourself by creating 33 bridges and then deleting a bridge 
that wasn't the first one you created. When listing the bridges, the first 
one you created will show up again.

The userspace tool and kernel code will need to be rewritten.

cheers,
Bart

[Bridge] Re: Limitation in virtual bridge number

[Fermín Galán]

>> My question is due to certain tests that I have
>> performed, the number of virtual bridges cann't be
>> greater than 32. Triying to add the 33rd bridge
>> with 'brctl addbr' works, but causes the removal
>> of the oldest one (the first in the 'brctl show' list):
>> the number of existing virtual bridges is never
>> more than 32.
>
>There were two hard limits, first the command was limited.
>The new bridge-utils 0.9.7 should fix that.  Second, there
>was a kernel limit of 64 which was because of not wanting to
>allocate a lot of memory.  That is now removed in 2.6.5 (post -rc3)
>and I tested with 300+ bridges.

Linux kernel 2.6.5 has been released today, but when the 0.9.7
release of bridge-utils will be released? (in
http://bridge.sourceforge.net/download.html
the last release available for download is 0.9.6)

Thanks!

-------
Fermín