Re: [[e-mail]: New Version Notification for draft-jones-6man-historic-rfc2675-00.txt]

[神明達哉 <[e-mail]>]

At Wed, 8 May 2019 18:07:51 +0200,
Ole Troan <[e-mail]> wrote:

> > We have put this together to change the status of RFC2675 to Historic
> > and would like to request discussion in the working group.
>
> IPv6 jumbograms was intended for some super computer inter connect with a
massive MTU.
> I don't know of any use of it, but is it harmful if the specification is
left there in place?
>
> I don't expect any implementation supporting it unless they also support
data-link layers with an MTU > 64K.

FWIW, (most if not all) BSD variants have been supporting jumbograms
for many years (admittedly I don't know if it's still working as
originally implemented, but the code is still there).  When I worked
on the implementation I confirmed its behavior with a loopback
interface configured to have an MTU larger than 64KB.  In that sense,
this statement of the draft is probably too strong:

   This also removes the need for testing Jumbogram support, which
   otherwise require links with a MTU greater than 65,535 bytes, making
   testing of implementations impractical without significant effort.

It's not a straightforward effort, but I don't think it requires a
"significant" one.

In any case, I agree there has been probably no real world deployment
of jumbograms.  I don't have a strong opinion about whether to
deprecate it.

--
JINMEI, Tatuya