pontification bloat (was 10GE TOR port buffers (was Re: 10G switch recommendaton))

Randy Bush randy at psg.com
Sat Jan 28 01:31:20 UTC 2012

>> 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

> 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


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