[149084] in North American Network Operators' Group
Re: pontification bloat (was 10GE TOR port buffers (was Re: 10G
daemon@ATHENA.MIT.EDU (Randy Bush)
Fri Jan 27 20:31:44 2012
Date: Sat, 28 Jan 2012 10:31:20 +0900
From: Randy Bush <randy@psg.com>
To: Leo Bicknell <bicknell@ufp.org>
In-Reply-To: <20120128012249.GB35610@ussenterprise.ufp.org>
Cc: North American Network Operators' Group <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
>> for those who say bufferbloat is a problem, do you have wred enabled
>> on backbone or customer links?
>
> For *most backbone networks* it is a no-op on the backbone. To be
> more precise, if the backbone is at least 10x, and preferably more
> like 50x faster than the largest single TCP flow from any customer
> it will be nearly impossible to measure the performance difference
> between a short FIFO queue and a WRED queue.
when a line card is designed to buffer the b*d of a trans-pac 40g, the
oddities on an intra-pop link have been observed to spike to multiple
seconds.
> To the customer, absolutely, whenever possible, which generally means
> when the hardware supports. Ideally with the queue length tuned to
> match the link speed of the customer port. The slower speed the
> customer port the more critical the tuning.
so, do you have wred enabled anywhere? who actually has it enabled?
(embarrassed to say, but to set an honest example, i do not believe iij
does)
randy
