Re: [HSSG] Jumbo frames
Thanks for your contribution.
A decision to support an project that mandates support of jumbo frames
would, in my opinion, take the study group into a quagmire. This would be
an effort towards a goal that was not even mentioned in the Call For
Interest nor mentioned in the discussion leading up to the vote on
forming the Study Group.
To go here would, I believe, be a betrayal of the trust laid on the group
Having said that, I do not believe that there is any reason why:
shouldn't build HSSG hardware in a manner that supports Jumbo
shouldn't (again) bring the topic up in 802.3
They just should not try to glue that requirement to this project rather
than use the appropriate process in 802.3.
There isn't anything inherently "wrong" with jumbo frames and
there isn't any reason why links and MACs shouldn't be able to transmit
and receive them. The issue comes when you try to integrate them into the
existing world. If you have a world of streets and railroad crossings
(sorry, I grew up in a railroad town) lots of folks will scream bloody
murder when you go from 50 car trains to 250 car trains. It is the
integration with other traffic at switch points that is the the
If folks want to build homogenous jumbo frame networks, more power to
them. We have never quite figured how to put that in the standard without
it seeming like we were trying to integrate them with legacy
Bottom line. This is an entirely different discussion from what we are
supposed to be doing which is higher speed.
I would request that those who want to jumbo frames set up their own
discussion forum on a different distribution list.
At 02:16 PM 8/10/2006 , Kevin Daines wrote:
Joel's statement below can be grossly misinterpreted.
He states that all system and silicon vendor supports jumbo frames. That
may be true but I highly doubt it. However, what is not true is that all
or the even the majority of the installed base of Ethernet gear supports
jumbo frames. In addition, many products on the market today do not
support jumbo frames (by products I mean both equipment and silicon).
During the P802.3as Frame Expansion project (soon to complete), UNH IOL
kindly tested hundreds of pieces of gear and combed through hundreds of
reports to determine the maximum frame size supported by Ethernet gear
(that had been submitted to UNH). While not exhaustive, the data
indicated a wide range of maximums from 1515 (not a typo) through 2K, 4K,
5K, and 9K and beyond.
Within P802.3as, we discussed jumbo frames at various
times. The following constitutes my recollection of the reasons against
"standardizing jumbo frames" (not ordered):
1) Interoperability with legacy gear
2) Increasing frame size is a slippery slope. Why 9KB? Why not something
larger, like 16KB or 64KB?
3) The network performance bottlenecks change over time. Each major
component of the network/system goes through improvements and upgrades,
which changes the requirements on other parts of the
4) QoS (frame delay, frame delay variation, etc.) impacts
Chair, P802.3as TF
Note from archive attached below:
Subject: [HSSG] Topics for Consideration: Jumbo Frames
From: Joel Goergen <joel@xxxxxxxxxxxxxxxxxxx>
Date: Wed, 9 Aug 2006 11:23:42 -0700
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If I go to any search engine and input "jumbo ethernet frames chips", I will see that every system and silicon vendor supports jumbo ethernet frames.
My question is not wether to support jumbos, because we all already do ... my question is should we finally spec it out? I think we should, at a minimum, provision for it.