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

From: Ted Faber <[email-masked]>
Date: Mon, 9 Apr 2007 08:13:28 -0700

Mark and I would like to start a WG last call on the informational
document on TCP's reaction to soft ICMP errors on connection set-up:

        Title           : TCP's Reaction to Soft Errors
	Author(s)       : F. Gont
	Filename        : draft-ietf-tcpm-tcp-soft-errors-05.txt
	Pages           : 13
	Date            : 2007-4-4

http://www.ietf.org/internet-drafts/draft-ietf-tcpm-tcp-soft-errors-05.txt

Our understanding is that all feedback to date is reflected in this
version and that there are no known outstanding issues.  Please send
feedback (even if just of the form "yep, looks good").

This WGLC will end on Monday 23 Apr 2007.

Again, please send comments, especially of the form "I read it and think
it's fine."

-- 
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
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---

From: Ted Faber <[email-masked]>
Date: Mon, 9 Apr 2007 10:19:38 -0700

> http://www.ietf.org/internet-drafts/draft-ietf-tcpm-tcp-soft-errors-05.txt

Mark points out that I should mention that the last non-editorial change
to this draft was the addition of several omitted error codes from
Section 2 when the draft was revised from -04 to -05.  WGLC readers
should make sure that the draft does address all the codes.

There have been several editorial only revisions of this draft, so if
you had difficulties with tone or focus in earlier drafts, please have a
look and see if those issues have been addressed.

---

From: Arifumi Matsumoto <[email-masked]>
Date: Tue, 10 Apr 2007 14:17:02 +0900

Hi, all.

> look and see if those issues have been addressed.

I looked at changes in section 2, and I found that I couldn't even
parse these sentences(2nd paragraph of Section 2).
Surely, I know that I'm not good at English, but aren't these a bit 
complicated ?

I like the methods proposed in this draft, but I feel more comfortable
if these sentences are written in plainer English.

Best regards,

-- 
Arifumi Matsumoto
    IP Technology Expert Team
    Secure Communication Project
    NTT Information Sharing Platform Laboratories
    E-mail: [email-masked]

---

From: Fernando Gont <[email-masked]>
Date: Wed, 11 Apr 2007 02:11:57 -0300

>Surely, I know that I'm not good at English, but aren't these a bit

Do you suggest to list the messages in a bulleted-list, or what?

Like:

  o Destination unreachable -- codes 0, 1 and 5
  o Time exceeded -- codes 0 and 1
  o Parameter problem

or what?

Thanks,

-- 
Fernando Gont
e-mail: [email-masked] || [email-masked]
PGP Fingerprint: 7809 84F5 322E 45C7 F1C9 3945 96EE A9EF D076 FFF1

---

From: Arifumi Matsumoto <[email-masked]>
Date: Wed, 11 Apr 2007 15:17:38 +0900

>  o Time exceeded -- codes 0 and 1

Firstly, I couldn't get that the first sentence
corresponds to the second one.
To clarify the mapping between ICMP and ICMPv6,
how about using a table like below.

-----
         ICMP                        ICMPv6
 
o Destination unreachable --- Destination Unreachable
  (0,1,5)                     (0,3)

o Time Exceeded (0,1)     --- Time Exceeded(0,1)

o Parameter Problem       --- Parameter Problem(0,1,2)
-----

The table above shows the mapping of ICMP erorr *types*.
If you want to clarify the mapping of codes, these codes
in the table above should be expanded like below.

-----
         ICMP                        ICMPv6
 
o Destination unreachable 0 --- Destination Unreachable 0
                          1 ---                         3
                          5 ---                         ?
...
-----

Kindest regards.

---

From: Mark Allman <[email-masked]>
Date: Wed, 11 Apr 2007 10:27:27 -0400

> Mark points out that I should mention that the last non-editorial
> change to this draft was the addition of several omitted error codes
> from Section 2 when the draft was revised from -04 to -05.  WGLC
> readers should make sure that the draft does address all the codes.

I just did some diff-ing and the old and new paragraphs are appended
below.  But, basically rev -04 covers these codes:

  ipv4 dest unreach: 0, 1, 5
  ipv6 type 1: 0, 3

and rev -05 covers these:

  ipv4 dest unreach: 0, 1, 5
  ipv4 time exceeded: 0, 1
  ipv4 param problem
  ipv6 dest unreach: 0, 3
  ipv6 time exceeded: 0, 1
  ipv6 param problem: 0, 1, 2

Just in terms of coverage this seems like a pretty significant change.

Fernando- Can you explain why you did this?  And, in particular, did you
receive feedback that stacks are using this expanded list?  (This is
targeted as an informational document about what stacks do, not as a
standards change.)

Thanks,
allman

-04:
   The Host Requirements RFC [RFC1122] states, in section 4.2.3.9., that
   the ICMP "Destination Unreachable" messages that indicate soft errors
   are ICMP codes 0 (network unreachable), 1 (host unreachable), and 5
   (source route failed).  Even though ICMPv6 didn't exist when
   [RFC1122] was written, one could extrapolate the concept of soft
   errors to ICMPv6 Type 1 Codes 0 (no route to destination) and 3
   (address unreachable).

-05:
   The Host Requirements RFC [RFC1122] states, in Section 4.2.3.9., that
   the ICMP messages that indicate soft errors are ICMP "Destination
   Unreachable" codes 0 (network unreachable), 1 (host unreachable), and
   5 (source route failed), ICMP "Time Exceeded" codes 0 (time to live
   exceeded in transit) and 1 (fragment reassembly time exceeded), and
   ICMP "Parameter Problem".  Even though ICMPv6 didn't exist when
   [RFC1122] was written, one could extrapolate the concept of soft
   errors to ICMPv6 "Destination Unreachable" codes 0 (no route to
   destination) and 3 (address unreachable), ICMPv6 "Time Exceeded"
   codes 0 (Hop limit exceeded in transit) and 1 (Fragment reassembly
   time exceeded), and ICMPv6 "Parameter Problem" codes 0 (Erroneous
   header field encountered), 1 (Unrecognized Next Header type
   encountered) and 2 (Unrecognized IPv6 option encountered).

---

From: Fernando Gont <[email-masked]>
Date: Wed, 11 Apr 2007 21:03:38 -0300

At 11:27 a.m. 11/04/2007, Mark Allman wrote:

>Fernando- Can you explain why you did this?

Carlos Pignataro sent me off-list feedback. As part of his feedback, 
he asked why the other codes were not included in the list. I 
re-checked the draft and RFC1122, and it turns out I simply missed 
them (actually, the original paragraph had sort of been copied 
verbatim from the v6onbydefault draft that had given birth to the 
soft errors draft. And the newly incorporated codes were already 
missing in the v6onbydefault draft). I checked the source code of the 
referenced implementations, and they process all the referenced error 
messages in the same way. That's why I included them.

>And, in particular, did you receive feedback that stacks are using 
>this expanded list?  (This is

I looked at the source code myself.

---

From: Carlos Pignataro <[email-masked]>
Date: Wed, 11 Apr 2007 21:32:21 -0400

Mark,

> targeted as an informational document about what stacks do, not as a

I sent some unicast comments/questions to Fernando a few weeks ago about
soft-errors-04; the (translated) one that likely prompted this change is:

----->8-----

2. Error Handling in TCP

###CP> Question: Is there any specific reason why you only consider
###CP> Unreach 0, 1 y 5 as soft errors? And not e.g. timeexceeded?
###CP> RFC1112 says they should be handled the same way:

http://tools.ietf.org/html/rfc1122

            o    Time Exceeded -- codes 0, 1

                 This should be handled the same way as Destination
                 Unreachable codes 0, 1, 5 (see above).

            o    Parameter Problem

                 This should be handled the same way as Destination
                 Unreachable codes 0, 1, 5 (see above).

----->8-----

Thanks,

--Carlos.

> ------------------------------------------------------------------------
> 

-- 
--Carlos Pignataro.
Escalation RTP - cisco Systems

---

From: Mark Allman <[email-masked]>
Date: Wed, 11 Apr 2007 22:53:07 -0400

> I checked the source code of the referenced implementations, and they
> process all the referenced error messages in the same way. That's why
> I included them.

Fair enough.  Thanks for the explanation.

Input on this would certainly be good here folks.  I think that this
change needs some positive feedback before we move forward.

allman

---

From: Mark Allman <[email-masked]>
Date: Tue, 24 Apr 2007 23:46:24 -0400

> This WGLC will end on Monday 23 Apr 2007.

Folks-

We received nearly no feedback on this WGLC.  Since this draft has been
contentious in the past we need some review before passing it along to
the IESG.  We are therefore extending the WGLC until May 15.  Please
take a few minutes and look over the draft and send comments.  As Ted
notes above, even if you think the draft looks fine a one-sentence note
that says this would be very much appreciated.

Thanks,
allman