dummynet dropping too many packets

rihad rihad at mail.ru
Mon Oct 5 09:29:04 UTC 2009


Eugene Grosbein wrote:
> On Mon, Oct 05, 2009 at 01:53:20PM +0500, rihad wrote:
> 
>> As you can see the drops gradually went away completely at about 4:00 
>> a.m., and started coming up at about 10:30 a.m., although at a lower 
>> rate, probably thanks to me bumping "ipfw ... queue NNN" up to 5000 at 
>> 10a.m. this morning. The traffic flow between 4a.m. and 10:30a.m., the 
>> "quiet" times, is about 200-330 mbit/s 5 minute average, without a 
>> single drop. But after that, in come the drops, no matter how high I set 
>> the queue. Should I try 10000 slots? 20000?
> 
> First switch from taildrop (default) to GRED, it is designed to fight
> your problem.
> 
Oh, I almost forgot... Right now I've googled up and am reading this 
intro: http://www-rp.lip6.fr/~sf/WebSF/PapersWeb/iscc01.ps

So turning to GRED would turn my FreeBSD router from dumb into a smart 
router that knows TCP? I thought pushing bits around at a lower level, 
and a sufficient queue size were enough.
Still not sure why increasing queue size as high as I want doesn't 
completely eliminate drops.


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