nanog mailing list archives

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


From: bas <kilobit () gmail com>
Date: Sat, 28 Jan 2012 00:30:35 +0100

Hi,

The margin on a top-of-rack switch is very low.  48 port gige with
10GE uplinks are basically commodity boxes, with plenty of competition.
Saving $100 on the bill of materials by cutting out some buffer
makes the box more competitive when it's at a $2k price point.

The list of 10GE TOR switches I sent earlier are list from $20K to $100K
So actual purchase cost for us would be $10K to $30K
$500 for some (S)(Q)(bla)RAM shouldn't hold back a vendor from
releasing a bitchin switch....

Again this argument does not explain why there are 1GE aggregation
switches with deep buffers..

Also, as was pointed out to me privately, it is also important to loook
at adaptive queue management features.  The most famous is WRED, but
there are other choices.  Having a queue management solution on your
routers and switches that works in concert with the congestion control
mechanism used by the end stations always results in better goodput.
Many of the low end switches have limited or no AQM choices, while the
higher end switches with fancier ASICs can default to something like
WRED.  Be sure it is the deeper buffers that are making the difference,
and not simply some queue management.

All true... Still no reason why not to offer a deep buffer TOR...


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