On 02/07/2017 05:06 PM, [email protected] wrote: > >>> Could you expand on your view of how this pertains to advancing >>> RFC1981? >>> >> It's called last call input. My input is that this document needs >> to be more realistic in noting that, for all intents, ICMP-based >> MTU discovery isn't viable and that other methods need to be >> *expected*, not just that they're available. > > Right, but if you are correct that ICMP-based MTU discovery is not > viable then this document should not be advanced. At the same time > for many protocols we have nothing else. An operator can break any > protocol if that's their policy. And that's the breakage we're > talking about here, not any issues with the protocol specification. > > There is a philosophical aspect of this. (Which I'm not the best > person to represent as I skipped my University studies in philosophy > and used the student loan to buy a motorcycle... (and only read the > art of motorcycle maintenance years later) ) This is a tussle. The > IETF specifies protocols under the assumption that operators treat > those protocols largely as specified. The 5-10% failure of PMTUD > messages may be caused by misconfiguration, misunderstanding or > mis-intent... Many of our protocols are suffering from the same fate. > Should the IETF adjust all its protocols to be as middlebox friendly > as possible? You can make this argument about IPv6 fragments, any > packet with IPv6 extension headers, IPv4 fragments. Or anything but > TCP port 443/80 and UDP port 53 for that matter. Are we as the IETF > going to continue standardising protocols to work as best as they > possible can, ignoring protocol abuse, or are we going to bend over > and do whatever it takes to make it work for those 5-10% who've > actively broken the protocol? What about the 90-90% where the > protocols work as expected?
There are two things to note here: 1) the folk breaking PMTUD is probably not the guy suffering from that breakage. So the had that "bad-hevaed" nodes hurt the "well behaved" nodes (i.e., you cannot claim "you're shooting your own foot). 2) Being an engineering group I would expect our protocols to work in the real world -- that's the point of engineering: solving problems. At the end of the day, you can build stuff that works, or complain that way too many people are doing dumb things (for some meaning of "dumb"). -- But the later will not make protocols work, nor solve problems. In that sense, I agree with Joe, and Randy Bush here. Thanks, -- Fernando Gont SI6 Networks e-mail: [email protected] PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492
