RE: Jumbo Frames in 10GbE?

["Thirion, Walt" <wthirion@xxxxxxxxxx>]

Title: RE: Jumbo Frames in 10GbE?

Just because there is an IETF document that implementers are free to follow doesn't mean the base IEEE standard should be changed. Expanding the frame size can cause major incompatibility with previous implementations and that, in my opinion, would obviate one of the very reasons that ethernet continues to be successful.

Moreover, segmentation can be done with a smart network interface, thereby offloading the per packet load on the host without breaking the standard.

This does not mean, however, that hardware shouldn't be built that can handle larger packets. As I said, that is left to the implementer. If a network designer wants to turn that feature "on", he can do so at his own risk AND with the understanding it isn't a standard setup.

There is some precedent for this in the early days of ethernet in that many PHYs were capable of driving significantly longer cables than specified in the standard. Implementers were free to take advantage of this when they felt it had value. But, because it was non-standard, there was no guarantee that changing a piece of equipment on either end of the wire would still work over the longer cables. But it was their choice...

Walter Thirion
Level One Communications
512-407-2110

> -----Original Message-----
> From: owner-stds-802-3-hssg@xxxxxxxxxxxxxxxxxx
> [mailto:owner-stds-802-3-hssg@xxxxxxxxxxxxxxxxxx]On Behalf Of
> Joe Gwinn
> Sent: Monday, June 21, 1999 2:39 PM
> To: Booth, Brad
> Cc: HSSG_reflector (E-mail)
> 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
> level.
>
> 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
> >challenge
> >        >this they should bring a presentation to the next
> meeting providing
> >        detailed reasoning why this needs to change.
> >
> >        It strikes me that the issue of larger maximum
> packet sizes will likely
> >        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 theoretical
> >        packet loss rate.   I'm not sure how much effect
> this would have in
> >        practice, as most gigabit links achieve much better
> than 10^-12,
> >if they
> >        work at all.  Anyway, these items are ripe for
> debate and decision.
>
> **** end of message ****
>