nanog mailing list archives

RE: jumbo frames


From: "Rowland, Alan D" <alan_r1 () corp earthlink net>
Date: Fri, 27 Apr 2001 08:44:30 -0700


I am not an EE but maybe if you rephrased the question as

Which is greater, the cpu cycles to assemble/dissemble jumbo frames or the
additional cycles/bandwidth of more numerous ACK packets?

Then again, I may be way out of my depth here.

-Al

-----Original Message-----
From: Kurt Kayser [mailto:kurt () noris de]
Sent: Friday, April 27, 2001 8:07 AM
To: Tony Hain
Cc: Roeland Meyer; John Fraizer; Paul Lantinga; nanog () merit edu
Subject: Re: jumbo frames



Hi,

Isn't it a lot more cpu-intensive to 'collect' some 1500-byte frames
into some larger bucket, reassemble it into a jumbo-frame when the next
box has to chop it in order to send it out on a Sonet/PPP/etc interface
which 
might have a smaller MTU again?

Doesn't make too much sense to me. I guess that was Tony's aim as well..

Kurt
 
Roeland you are talking about jumbo frames from the end system lan, while
John is talking about only using the jumbo frames between the routers. My
point was that in John's environment the packets will all be 1500 since
the
packets are restricted to that size just to get to the router with the GE
interface. I understand that there are perf gains as long as the entire
path
supports the larger packets, but I don't understand the claim that having
a
bigger pipe in the middle helps.

Tony

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