Re: Traffic shaping

On Fri, Jul 21, 2006 at 05:39:31PM -0700, Steven Kurylo wrote:
> >If you are trying to ensure for example that VoIP traffic doesn't get
> >killed
> >by big file transfers, then you should probably look at this from a QOS/
> >prioritization perspective rather than strictly shaping/limiting. For
> >this,
> >look at diffserv at the switch or just using the IP TOS and something like
> >class based weighted fair queuing.
>
> Yeah I have all that down, and even some servers running it already.
> The problem is you have to specify separate download and upload
> speeds. I want to specify one speed for both direction - so its
> shared.
>
> If I have a 2Mb connection, I can upload at 2Mb, download at 2Mb, or
> do both simultaneously at 1Mb. So defining 2Mb on each direction
> won't work, because if I try to use both at once the most I'll get is
> 1Mb and I won't reach the queue limit of 2Mb (meaning the queue isn't
> the bottleneck, meaning shaping won't work properly). If I define 1Mb
> for each direction, I'll always be limited to 1Mb, regardless if the
> other direction is in use; that would leave idle bandwidth.

Ah, now I get ya. I don't think any of the off the shelf stuff will do what
you want, not even the commercial stuff.

I doubt there is an easy way to do it with pf in OpenBSD.

In iproute2, I thought there was a way to write and use your own shaping
algorithm but I can't find that in the how-to.

It sounds like what you are asking to do is share a queue between the
inbound and outbound interfaces and rate limit that queue to 2Mbps. I don't
think you can do this since queues are generally associated with an interface
(device). It might be worth tracking down the iproute2 mailing list and
asking there. Any other suggestions I'd have would be grasping at straws.
Received on Fri Jul 21 22:48:09 2006