[DNSOP] Re: [v6ops] Re: Fwd: New Version Notification - draft-ietf-dnsop-avoid-fragmentation-18.txt

[Paul Vixie <[e-mail]>]

On Thursday, July 4, 2024 7:05:22 AM PDT Tim Wicinski wrote:
> On Tue, Jul 2, 2024 at 9:26 PM David Farmer <[e-mail]> wrote:
> > 2. Also, maybe R5 should have text similar to R3 with "...the minimum
> > of...the interface MTU, the network MTU...and 1400 bytes..." Instead of
> > "It should use a limit of 1400 bytes, but a smaller limit MAY be used."
> 
> Something like this:
> 
> "UDP requestors should limit the requestor's maximum UDP payload size  to
> use the RECOMMENDED size of 1400 bytes, but a smaller limit MAY be used."

As before, I'd like to future-proof this document. 1400 may not survive and should not be a 
hard limit. If someone ever gets PLPMTUD working, or if local knowledge includes MTU 
over a topology as a static configuration, then the recommended value should be ignored, 
and the measured or locally defined limit should be the operational maximum for that 
datagram.

Thus, not only a smaller limit, but also a larger limit, may be sometimes used. This 
document need not enumerate all such cases, but should not require revision if 1400 turns 
out to be like 640KB -- not a sensible limit for all possible futures.

-- 
P Vixie