Pipe queues

Ian Smith smithi at nimnet.asn.au
Wed Dec 12 05:49:28 PST 2007

On Tue, 11 Dec 2007, Peter Jeremy wrote:
 > On Tue, Dec 11, 2007 at 12:31:00PM +0400, rihad wrote:
 > >Peter Jeremy wrote:
 > >> On Tue, Dec 11, 2007 at 09:21:17AM +0400, rihad wrote:
 > >>> And if I _only_ want to shape IP traffic to given speed, without 
 > >>> prioritizing anything, do I still need queues? This was the whole point.
 > >> No you don't.  I'm using pipes without queues extensively to simulate
 > >> WANs without bothering with any prioritisation.

Well, a pipe specified without a specific queue option uses a queue of
the default size of 50 slots, right?

 > >Great! One fine point remains, though:
 > ># ipfw pipe 1 config bw 128Kbit/s
 > >will use a queue of 50 slots by default. What good are they for, if I 
 > >didn't ask for queuing in the first place?

I think others have pointed out out that you need to queue packets for
bandwidth limitation, so a queue size of 0 makes no sense for that.

 > 'queue' is used in two distinct ways within the ipfw/dummynet code:
 > 1) There's a "queue" object created with 'ipfw queue NNN config ...'
 >    This is used to support WF2Q+ to allow a fixed bandwidth to be
 >    unevenly shared between different traffic types.
 > 2) There is a "queue" option on the "pipe" object that defines a FIFO
 >    associated with the pipe.

Yes it's confusing at first using the same keyword for a rule action and
for a configuration option, especially when an option of queues is 'pipe
pipe_nr' and an option for both pipes and queues is 'queue {slots|size}'

Your para above wouldn't go amiss in ipfw(8) for clarification, though
on the tenth reading it does start to sink in ..


 > Please excuse any delays as the result of my ISP's inability to implement
 > an MTA that is either RFC2821-compliant or matches their claimed behaviour.

exetel good, fixed IP, roll yer own (if you don't owe optus your soul :)

cheers, Ian

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