Re: Path MTU Hop-by-Hop Option

[Fernando Gont <[e-mail]>]

On 10/17/18 6:49 AM, Carsten Bormann wrote:
> On Oct 17, 2018, at 00:55, Bob Hinden <[e-mail]> wrote:
>>
>> This document specifies a new Hop-by-Hop IPv6 option that is used to
>>   record the minimum Path MTU
> 
> A while ago I proposed something similar to collect information about adaptation layer fragmentation MTUs (information about which is truly not available in any other way):
> 
> https://tools.ietf.org/html/draft-bormann-intarea-alfi-04
> 
> (I also only looked at the Internet layer here — leaving it as an exercise to put in transport/application protocol support.)
> 
> After mulling an initial version of the proposal, there was pretty much consensus that hop-by-hop options were not really available on the Internet.  So I put in an alternative way to collect the information, see above if you are interested.  Then at some point SPUD came along and I was hoping that would lead to a framework within in which this information could be better handled.
> 
> Maybe it’s time to pull the old draft out again.  The hop-by-hop option problem of course hasn’t gone away.

IPv6 EHs are not readily available on the public IPv6 Internet. See
RFC7872. While not included in RFC7872, my measurements indicate that
the same applies even to IPsec EHs. :(

Thanks,
-- 
Fernando Gont
SI6 Networks
e-mail: [e-mail]
PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492