Re: [HSSG] Topics for Consideration: Jumbo Frames

[Marcus Duelk <duelk@xxxxxxxxxx>]

Title:

Hi Arthur,

there is a nice little "tutorial" about the Pros and Cons
of jumbo frames at http://sd.wareonearth.com/~phil/jumbo.html,
it also includes actual frame size distribution measurement on the
MCI backbone from 1998 in which you can see that there are a lot
of frames >1500B from FDDI and other sources, they mention that
more than 50% of all traffic (measured in Bytes and not in packets)
come from packets >1500B. But, larger packets also have a clear
benefit to TCP/IP performance. The difference in store-and-forward
latency between 1.5kB and 9kB is negligible at higher speeds, time
of flight is much, much higher ...

Marcus


Arthur Marris wrote:

Joel, Mike,

   Don't jumbo frames increase latency in links where there is store and forward?

 

Arthur.  

Both my position and that of the customers I deal with is that higher speeds, 10gbps included, is more efficient with the larger packets.

no argument from me on this one, although the actual efficiency gained comparing 1.5 K frames to 9 K frames is only ~ 2%, but when you're on the cutting/bleeding edge of technology, every bit counts.

-- 
___________________________
Marcus Duelk
Bell Labs / Lucent Technologies
Data Optical Networks Research

Crawford Hill HOH R-237
791 Holmdel-Keyport Road
Holmdel, NJ 07733, USA
fon +1 (732) 888-7086
fax +1 (732) 888-7074