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

George Bonser gbonser at seven.com
Fri Jan 27 23:01:10 UTC 2012

> -----Original Message-----
> From: bas 
> Sent: Friday, January 27, 2012 2:54 PM
> To: George Bonser
> Subject: Re: 10GE TOR port buffers (was Re: 10G switch recommendaton)
> While I agree _again_!!!!!
> It does not explain why TOR boxes have little buffers and chassis box
> have many.....

Because that is what customers think they want so that is what they sell.  Customers don't realize that the added buffers are killing performance.

I have had network sales reps tell me "you want this switch over here, it has bigger buffers" when that is exactly the opposite of what I want unless I am sending a bunch of UDP through very brief microbursts.  If you are sending TCP streams, what you want is less buffering. Spend the extra money on more bandwidth to relieve the congestion.

Going to 4 10G aggregated uplinks instead of 2 might get you a much better performance boost than increasing buffers.  But it really depends on the end to end application.

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