Joe,
All things are fragile. That's one of life's realities.
But some things are more fragile than others.
Ron
Juniper Business Use Only
-----Original Message-----
From: Joe Touch <[email protected]>
Sent: Thursday, August 15, 2019 10:21 AM
To: Ron Bonica <[email protected]>
Cc: Brian E Carpenter <[email protected]>; Alissa Cooper
<[email protected]>; Tom Herbert <[email protected]>; Joel Halpern
<[email protected]>; [email protected]; int-area
<[email protected]>; IESG <[email protected]>; intarea-chairs
<[email protected]>
Subject: Re: [Int-area] Alissa Cooper's Discuss on
draft-ietf-intarea-frag-fragile-15: (with DISCUSS and COMMENT)
Well, there’s the tautology that “it worked when it worked”.
Given that’s basically the rule that defines *everything* in the Internet, it’s
baffling we need to say it again here, but if we did, we could simply state:
“The Internet is a best-effort system and lacks a formal validation or
conformance mechanism. Like any other protocol feature, IP fragmentation is
useful only when it actually works - both by successfully traversing routers
and other in-network devices and when it is correctly supported by endpoints.
As a consequence, like any other protocol feature, IP fragmentation MAY be used
by new protocols that validate its successful traversal and provide an
alternate as a backup.”
(and yes, if we’re going to try to imply that frag is limited, it really should
be clear that this is *no different than any other protocol feature* in the
Internet)
Joe
> On Aug 15, 2019, at 6:59 AM, Ron Bonica
> <[email protected]> wrote:
>
> Folks,
>
> Has anyone proposed text that:
>
> a) satisfies Alissa's request
> b) satisfies the WG
>
> If not, do we believe that such text could possibly exist?
>
> Ron
>
>
>
>
> Juniper Business Use Only
>
> -----Original Message-----
> From: Brian E Carpenter <[email protected]>
> Sent: Tuesday, August 6, 2019 8:55 PM
> To: Alissa Cooper <[email protected]>; Tom Herbert
> <[email protected]>
> Cc: Joel Halpern <[email protected]>;
> [email protected]; int-area
> <[email protected]>; IESG <[email protected]>; intarea-chairs
> <[email protected]>
> Subject: Re: [Int-area] Alissa Cooper's Discuss on
> draft-ietf-intarea-frag-fragile-15: (with DISCUSS and COMMENT)
>
> On 07-Aug-19 12:11, Alissa Cooper wrote:
>> Hi Tom,
>>
>>> On Aug 6, 2019, at 5:41 PM, Tom Herbert <[email protected]> wrote:
>>>
>>> On Tue, Aug 6, 2019 at 1:30 PM Alissa Cooper via Datatracker
>>> <[email protected]> wrote:
>>>>
>>>> Alissa Cooper has entered the following ballot position for
>>>> draft-ietf-intarea-frag-fragile-15: Discuss
>>>>
>>>> When responding, please keep the subject line intact and reply to
>>>> all email addresses included in the To and CC lines. (Feel free to
>>>> cut this introductory paragraph, however.)
>>>>
>>>>
>>>> Please refer to
>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__www.ietf.org_i
>>>> e
>>>> sg_statement_discuss-2Dcriteria.html&d=DwIFaQ&c=HAkYuh63rsuhr6Scbfh
>>>> 0
>>>> UjBXeMK-ndb3voDTXcWzoCI&r=Fch9FQ82sir-BoLx84hKuKwl-AWF2EfpHcAwrDThK
>>>> P
>>>> 8&m=IUZsPOprgYi_5nBSPGeqNCLb8LwDMKCxRNeEBfcUZ5c&s=c7tAk-Lfr6pcQSMn1
>>>> x 1tdfjkQsL8F_NryIiq3caZ26k&e= for more information about IESG
>>>> DISCUSS and COMMENT positions.
>>>>
>>>>
>>>> The document, along with other ballot positions, can be found here:
>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__datatracker.ie
>>>> t
>>>> f.org_doc_draft-2Dietf-2Dintarea-2Dfrag-2Dfragile_&d=DwIFaQ&c=HAkYu
>>>> h
>>>> 63rsuhr6Scbfh0UjBXeMK-ndb3voDTXcWzoCI&r=Fch9FQ82sir-BoLx84hKuKwl-AW
>>>> F
>>>> 2EfpHcAwrDThKP8&m=IUZsPOprgYi_5nBSPGeqNCLb8LwDMKCxRNeEBfcUZ5c&s=lb6
>>>> u 0SVhJIFnTV7TdqeLiDBfadRxJkAxNEDqOvFqhyQ&e=
>>>>
>>>>
>>>>
>>>> -------------------------------------------------------------------
>>>> -
>>>> --
>>>> DISCUSS:
>>>> -------------------------------------------------------------------
>>>> -
>>>> --
>>>>
>>>> Thanks for writing this document.
>>>>
>>>> Section 6.1 says:
>>>>
>>>> "Developers MAY develop new protocols or applications that rely on
>>>> IP fragmentation if the protocol or application is to be run only
>>>> in environments where IP fragmentation is known to be supported."
>>>>
>>>> I'm wondering if there should be a bit more nuance here to make the
>>>> recommendation clearer. Do we think there is a case where an
>>>> application protocol developed in the IETF will be known to only
>>>> run in environments where fragmentation is supported? If we don't
>>>> think developing such a protocol would be in scope for the IETF,
>>>> then I'm wondering if that case should be called out explicitly with a
>>>> stronger normative requirement.
>>>>
>>> Alissa,
>>>
>>> Are you distinguishing between protocol development and application
>>> development?
>>
>> I’m specifically wondering about application protocols (as distinct from
>> other protocols) developed in the IETF (as distinct from developed
>> elsewhere). Sometimes we use BCPs to guide future work in the IETF
>> specifically, and it seemed to me that in that specific slice —
>> IETF-developed application protocols — we may be able to make a stronger
>> recommendation since we can’t be sure of the environment in which any given
>> application protocol would be deployed (I think, but would be open to
>> arguments otherwise).
>
> fwiw, I agree with what I think Alissa is saying. Unless we actually
> *implement* a mechanism to define and support limited domains
> (draft-carpenter-limited-domains) protocol designers cannot safely make
> assumptions such as "fragmentation works".
>
> Maybe this paragraph needs to be more of a health warning than a somewhat
> dubious RFC2119 statement. At least, "should not ... unless" might be a
> better formulation than "MAY ... if".
>
> Brian
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