Re: [tcpm] WGLC: TCP's Reaction to Soft Errors

On Fri, May 04, 2007 at 03:34:01PM -0700, Joe Touch wrote:
> 
> 
> Fernando Gont wrote:
> > At 13:44 03/05/2007, Ted Faber wrote:
> > 
> >> This seems to have generated some discussion, and seems to me (with
> >> my chair hat) to be an interaction worth mentioning in the tcpm draft.
> >> I think that would be a lot easier to accomodate (i.e., easy to add
> >> without another WGLC round) if someone were to suggest a paragraph or 2
> >> to be included in the tcpm draft and we hammered out a quick consensus.
> >>
> >> Any takers?
> >>
> >> (And if I'm reading the group's take wrong here, let me know that, too.)
> > 
> > So far Saikat is for documenting this, and Joe for not doing so.
> 
> Largely because it focuses on behavior that is not BEHAVE compliant;
> IMO, this sort of thing should be for a BEHAVE-based 'implementation
> problems' doc. If we want to add this, are we adding all other known
> ICMP implementation errors?

It seems to me (hat's off) that a pitfall that this soft-errors response
causes when combined with an IETF BCP is a more constrained and
important case than an interaction between this response and a buggy
system.  I agree it needs to be flagged in the NAT literature as a
pitfall for BEHAVE NAT implementers.  I think it should also be flagged
here for TCP implementers who want to understand the ramifications of
this design choice (soft error == hard error during connection setup).
It's worth calling out against all the other potential design choices
because it conflicts with a BCP - implementation advice - rather than
just against observed behavior.

In the same way the soft-errs doc points out that a TCP that treats soft
errors as hard is out of step with ICMP and TCP standards, I think it
should point out that the decision violates the assumptions of the
BEHAVE BCP.

Anyone else care?  If it's just Saikat and me who think this warning
needs to be added, I'm not opposed to having the draft go to RFC as-is.

-- 
Ted Faber
http://www.isi.edu/~faber           PGP: http://www.isi.edu/~faber/pubkeys.asc
Unexpected attachment on this mail? See http://www.isi.edu/~faber/FAQ.html#SIG