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Jumbo Frames (was Re: MAE-EAST Moving? from Tysons corner to reston VA. )
From: "Bora Akyol" <akyol () akyol org>
Date: Sun, 18 Jun 2000 22:20:56 -0700


Same question once again.

As long as most end users are running Ethernet, Fast Ethernet, DSL or Cable
Modems, what is the point of jumbo frames/packets other than transferring
BGP tables really fast. Did any one look into how many packets are moved
through an OC-48 in 1 seconds. (approx. 6 million 40 byte packets). I think
even without jumbo frames, this bandwidth will saturate most CPUs.

Jumbo frames are pointless until most of the Internet end users switch to a
jumbo frame based media.

Yes, they look cool on the feature list (we support it as well). Yes they
are marginally more efficient than 1500 byte MTUs ( 40/1500 vs 40/9000). But
in reality, 99% or more of the traffic out there is less than 1500 bytes. In
terms of packet counts, last time I looked at one, 50% of the packets were
around 40 byte packets (ACKs) with another 40% or so at approx 576 bytes or
so.

What is the big, clear advantage of supporting jumbo frames?

Bora



----- Original Message -----
From: "brett watson" <bwatson () mibh net>
To: "Richard A. Steenbergen" <ras () e-gerbil net>
Cc: "RJ Atkinson" <rja () inet org>; <nanog () merit edu>
Sent: Saturday, June 17, 2000 11:11 PM
Subject: Re: MAE-EAST Moving? from Tysons corner to reston VA.




On Sat, 17 Jun 2000, RJ Atkinson wrote:

Which OSs don't yet support this ?

Not OS, drivers. Pick your favorite OS with GigE support, grep jumbo the
drivers section. In a few cases the unix drivers support jumbo frames
and
the reference vendor drivers do not, in a couple its the other way
around.
I see its getting better though, there is more support then there used
to
be the last time I looked.

you'd be surprised how many vendors aren't even considering supporting
jumbo frames, or worse don't understand why you'd want to.

several vendors of optical gear (dwdm) i've run into lately weren't
even going to do it and didn't know why they should.  this only
applies to vendors doing native GE, not vendors going true transparent
optics.

-b





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