Internet Exchanges supporting jumbo frames?

Sat Mar 19 21:49:01 UTC 2016

The factor of 6 was just in reduction of overhead.  Granted in the greater scheme of things the overall 4% is relatively insignificant, but there have been many times when doing multiple 10-100+GB transfers that I would have welcomed a 4% reduction of time spent twiddling thumbs!

-----Original Message-----
From: Jakob Heitz (jheitz) [mailto:jheitz at cisco.com] 
Sent: Saturday, March 19, 2016 00:34
To: Tim McKee
Cc: Dale W. Carder; nanog at nanog.org
Subject: Re: Internet Exchanges supporting jumbo frames?

You would hardly notice it.
Helium is 4 times as heavy as hydrogen, but only marginally less buoyant.

Header overhead:
Ethernet=38
IPv4=20
TCP=20
Total=78
Protocol efficiency:
1500: 1500/1578 = 95%
9000: 9000/9078 = 99%

That's 4% better for a TCP packet, not 600%.

Thanks,
Jakob.

> On Mar 18, 2016, at 6:45 PM, Tim McKee <tim at baseworx.net> wrote:
> 
> I would hazard a guess that reducing the packet header overhead *and* the Ethernet interframe gap time by a factor of 6 could make enough of an improvement to be quite noticeable when dealing with huge dataset transfers.
> 
> Tim McKee
> 
> -----Original Message-----
> From: NANOG [mailto:nanog-bounces at nanog.org] On Behalf Of Jakob Heitz 
> (jheitz)
> Sent: Friday, March 18, 2016 18:21
> To: Dale W. Carder
> Cc: nanog at nanog.org
> Subject: RE: Internet Exchanges supporting jumbo frames?
> 
> Then it's mainly TCP slowstart that you're trying to improve?
> 
> Thanks,
> Jakob.
> 
>> -----Original Message-----
>> From: Dale W. Carder [mailto:dwcarder at wisc.edu]
>> Sent: Friday, March 18, 2016 3:03 PM
>> To: Jakob Heitz (jheitz) <jheitz at cisco.com>
>> Cc: nanog at nanog.org
>> Subject: Re: Internet Exchanges supporting jumbo frames?
>> 
>> Thus spake Jakob Heitz (jheitz) (jheitz at cisco.com) on Fri, Mar 18, 2016 at 09:29:44PM +0000:
>>> What's driving the desire for larger packets?
>> 
>> In our little corner of the internet, it is to increase the 
>> performance of a low number of high-bdp flows which are typically dataset transfers.
>> All of our non-commercial peers support 9k.
>> 
>> Dale
> 
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