Re: [v6ops] PMTUD issue discussion

[Fernando Gont <[e-mail]>]

Hi, Fred,

On 08/26/2014 12:13 PM, Fred Baker (fred) wrote:
>> I think it would be useful to see the discussion of this measure 
>> and its applicability/tradeoffs in the draft.
> 
> It seems like it might have value to also test the interaction
> with various initial window settings, and look at its inclusion in
> other relevant OS’s including FreeBSD, Windows, and MacOSX.

FWIW, while RFC4821 can work without relying on PLPMTUD at all, some
OSes (such as Windows) only fall back to ICMP-less PMTUD as part of
"ICMP blackhole detecion" -- and they have been doing this for years
now...


> My reading of 4821 says it’s grand theory, but I’m not precisely
> sure how I would write the code. As an initial setting, for
> example, I could imagine sending an initial burst containing a 9K
> byte packet, a 1500 byte

Unlikely if the underlying link-layer technology is Ethernet (PMTUD
will never be assumed to be larger than your own MTU).

Additionally, I doubt you'd employ different packet
sizes/assumed_PMTUDs all at once.

Thanks,
-- 
Fernando Gont
SI6 Networks
e-mail: [e-mail]
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