ipprecedence

Eugene Grosbein eugen at kuzbass.ru
Sun Jul 6 02:45:00 PDT 2003


Luigi Rizzo wrote:

> > > zero-bw pipes are only useful to add delay or to count
> > > traffic (e.g. using masks), but will never cause queues
> > > to build up and so won't help in your case.
> >
> > That's sad; it would be nice if dummynet would create queues for zero-bw
> > pipes and perform dequeueing basing on weights.
> 
> that would be magic, not engineering :)
> 
> How could the scheduler decide when to drain the queue ?

It should move packets from zero-bw WFQ pipe the interface FIFO
as soon as possible but should consider weights 
(100 packets from one queue then 1 from another and so on).

> As I said, there _is_ a way -- if you know the device where the
> queueing occurs (say 'wi0'), and are willing to modify the driver,
> you can insert a call to if_tx_rdy() in the place where the device
> signals that the 'transmit ring' (see my previous msg) is ready,
> and then use 'bandwidth wi0' to set the rate of the pipe.

Well, I could do that but my configuration is different.
My FreeBSD router does not have WaveLan interface. Instead, I have
another device (named "RWR") with one 10Mbit Ethernet interface
and one 2Mbit WaveLan interface. RWR can pass traffic with non-zero
IP Precedence first. FreeBSD has fxp(4) 100Mbit Ethernet card that
connects it to the RWR. So I see no reason to patch fxp(4) here :-)

Eugene


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