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Re: Jumbo Frames in 10GbE?

I have heard some folk lore that the CRC-32 algorithm rather suddenly falls
apart (in terms of high detection rate) above the present maximum Ethernet
block size (1518 bytes).

Indeed, there has been some pleas for "no superpackets, please!" on this

This should be carefully checked before making any great leaps, tempting
though it may be from an overhead perspective.

Larry Miller
Nortel Networks

-----Original Message-----
From: Joe Gwinn <>
To: Booth, Brad <>
Cc: HSSG_reflector (E-mail) <>
Date: Monday, June 21, 1999 12:34 PM
Subject: Jumbo Frames in 10GbE?

>At 4:24 PM 99/6/17, Booth, Brad wrote:
>>Just a small point.  One of the objectives that passed with greater than
>>75% in Coeur d'Alene was to "preserve minimum and maximum FrameSize of
>>current 802.3 Std."
>I don't know that the issue is going to stay decided all that long, based
>on the recent article "Jumbo Frames gather support" (Jeff Caruso, Network
>World, 14 June 1999, page 6), which states that IETF has published a
>working document proposing that ethernet frames be made larger than the
>current 1,500-byte maximum, the basic rationale being to reduce the packet
>rate and thus load on packet-handling components of the system.  In short,
>this is a system issue, and cannot really be decided solely at the MAC
>If jumbo frames are to come, 10GbE would be a logical place to start.
>The issue will ultimately be decided by an IEEE Ballot Group, not a
>Plenary.  If the market is really going to bigger packets, as this article
>implies, it will be hard to resist.
>Joe Gwinn
>The above is in response to the following:
>>        >Issues 3 - Bit Error Rate
>>        >The assumption will be that this is 10-12. If someone wishes to
>>        >this they should bring a presentation to the next meeting
>>        detailed reasoning why this needs to change.
>>        It strikes me that the issue of larger maximum packet sizes will
>>        come up, just as it did for GbE.  If 10GbE goes to 9 KB packets,
>>the design
>>        center BER would need to go to 10^-13 to maintain the same
>>        packet loss rate.   I'm not sure how much effect this would have
>>        practice, as most gigabit links achieve much better than 10^-12,
>>if they
>>        work at all.  Anyway, these items are ripe for debate and
>**** end of message ****