Re: [Int-area] Alissa Cooper's No Objection on draft-ietf-intarea-frag-fragile-16: (with COMMENT)

[Bob Hinden <[e-mail]>]

Tom,

> On Sep 3, 2019, at 1:33 PM, Tom Herbert <[e-mail]> wrote:
> 
> Bob,
> 
> I agree with Fred. Note, the very first line of the introduction:
> 
> "Operational experience [Kent] [Huston] [RFC7872] reveals that IP
> fragmentation introduces fragility to Internet communication”.

Yes, that text in in the first paragraph of the Introduction
> 
> This attempts to frame fragmentation as being generally fragile with
> supporting references. However, there was much discussion on the list
> about operational experience that demonstrates fragmentation is not
> fragile. In particular, we know that fragmentation with tunnels is
> productively deployed and has been for quite some time. So that is the
> counter argument to the general statement that fragmentation is
> fragile. With the text about tunneling included in the introduction I
> believe that was sufficient balance of the arguments, but without the
> text the reader could be led to believe that fragmentation is fragile
> for everyone all the time which is simply not true and would be
> misleading.

Yes, but we are discussing some text from the Introduction that to my read didn’t say anything useful so I removed it.  The substantive text about tunneling in in Section 3.5.  The Introduction, is just the introduction.  The text was:

   This document acknowledges that in some cases, packets must be
   fragmented within IP-in-IP tunnels [I-D.ietf-intarea-tunnels].
   Therefore, this document makes no additional recommendations
   regarding IP-in-IP tunnels.

Why is that more useful than what is in 3.5?  If it’s not making a recommendation, why call this out in the introduction.  There are lot of other things it doesn’t make recommendations about that aren’t in the Introduction either.

Bob

> 
> Speaking of balance, the introduction also mentions that:
> 
> "this document recommends that upper-layer protocols address the
> problem of fragmentation at their layer"
> 
> But the "problem" of fragmentation is in intermediate devices that
> don't properly handle it as the draft highlights. So it seems like
> part of addressing the problem should also be to fix the problem! That
> is implementations should be fixed to deal with fragmentation. IMO,
> this should be another high level recommendation that is mentioned in
> the introduction.

I am serving as document editor.  This to my understanding has been through w.g. last call and now IESG review.
> 
> Tom
> 
> 
> 
> Tom
> 
> 
> 
> 
> 
> On Tue, Sep 3, 2019 at 1:01 PM Bob Hinden <[e-mail]> wrote:
>> 
>> Fred,
>> 
>>> On Sep 3, 2019, at 12:45 PM, Templin (US), Fred L <[e-mail]> wrote:
>>> 
>>> Bob,
>>> 
>>>> -----Original Message-----
>>>> From: Bob Hinden [mailto:[e-mail]]
>>>> Sent: Tuesday, September 03, 2019 9:10 AM
>>>> To: Templin (US), Fred L <[e-mail]>
>>>> Cc: Bob Hinden <[e-mail]>; Joe Touch <[e-mail]>; Alissa Cooper <[e-mail]>; Joel Halpern
>>>> <[e-mail]>; [e-mail]; [e-mail]; IESG <[e-mail]>; intarea-
>>>> [e-mail]
>>>> Subject: Re: [Int-area] Alissa Cooper's No Objection on draft-ietf-intarea-frag-fragile-16: (with COMMENT)
>>>> 
>>>> Fred,
>>>> 
>>>>> On Sep 3, 2019, at 7:33 AM, Templin (US), Fred L <[e-mail]> wrote:
>>>>> 
>>>>> Why was this section taken out:
>>>>> 
>>>>>> 1.1.  IP-in-IP Tunnels
>>>>>> 
>>>>>> This document acknowledges that in some cases, packets must be
>>>>>> fragmented within IP-in-IP tunnels [I-D.ietf-intarea-tunnels].
>>>>>> Therefore, this document makes no additional recommendations
>>>>>> regarding IP-in-IP tunnels.
>>>> 
>>>> This text in the Introduction was removed because, as noted in Warren Kumari
>>>> Comment (2019-08-07 for -15), this didn’t need to be in the introduction, and it didn’t say very much that isn’t described later in the
>>>> document.
>>>> 
>>>> The normative text in Section 5.3. "Packet-in-Packet Encapsulations” is unchanged.  I think Section 5.3 covers the topic.  It includes the
>>>> reference to [I-D.ietf-intarea-tunnels].
>>> 
>>> While I agree that both passages supply a working vector to 'intarea-tunnels',
>>> the two strike very different tones. The former gives a balanced citation, while
>>> the latter calls it a "corner case" - twice!
>>> 
>>> Whether we like it or not, fragmentation and encapsulation will continue to
>>> be associated with each other no matter what gets documented here. So,
>>> a respectful handoff to 'intarea-tunnels' would be appreciated.
>> 
>> You are talking about text in the Introduction of the document.
>> 
>> The important substance relating to tunnels is in Section 5.3.   The text is:
>> 
>>   5.3.  Packet-in-Packet Encapsulations
>> 
>>   In this document, packet-in-packet encapsulations include IP-in-IP
>>   [RFC2003], Generic Routing Encapsulation (GRE) [RFC2784], GRE-in-UDP
>>   [RFC8086] and Generic Packet Tunneling in IPv6 [RFC2473].  [RFC4459]
>>   describes fragmentation issues associated with all of the above-
>>   mentioned encapsulations.
>> 
>>   The fragmentation strategy described for GRE in [RFC7588] has been
>>   deployed for all of the above-mentioned encapsulations.  This
>>   strategy does not rely on IP fragmentation except in one corner case.
>>   (see Section 3.3.2.2 of RFC 7588 and Section 7.1 of RFC 2473).
>>   Section 3.3 of [RFC7676] further describes this corner case.
>> 
>>   See [I-D.ietf-intarea-tunnels] for further discussion.
>> 
>> Seems fine to me, in tone and substance.
>> 
>> Bob
>> 
>> 
>>> 
>>> Fred
>>> 
>>>> Bob
>>>> 
>>>> 
>>>>> 
>>>>> Tunnels always inflate the size of packets to the point that they may exceed
>>>>> the path MTU even if the original packet is no larger than the path MTU. And,
>>>>> for IPv6 the only guarantee is 1280. Therefore, in order to robustly support
>>>>> the minimum IPv6 MTU tunnels MUST employ fragmentation.
>>>>> 
>>>>> Please put this section of text back in the document where it belongs.
>>>>> 
>>>>> Thanks - Fred
>>>>> 
>>>>>> -----Original Message-----
>>>>>> From: Int-area [mailto:[e-mail]] On Behalf Of Joe Touch
>>>>>> Sent: Tuesday, September 03, 2019 7:06 AM
>>>>>> To: Alissa Cooper <[e-mail]>
>>>>>> Cc: Joel Halpern <[e-mail]>; [e-mail]; [e-mail]; The IESG
>>>> <[e-mail]>;
>>>>>> [e-mail]
>>>>>> Subject: Re: [Int-area] Alissa Cooper's No Objection on draft-ietf-intarea-frag-fragile-16: (with COMMENT)
>>>>>> 
>>>>>> Hi, all,
>>>>>> 
>>>>>> So let me see if I understand:
>>>>>> 
>>>>>> Alissa issues a comment.
>>>>>> 
>>>>>> We discuss this on the list and come to a rare consensus on a way forward.
>>>>>> 
>>>>>> The new draft is issued that:
>>>>>> 
>>>>>> a) ignores the list consensus
>>>>>> b) removes a paragraph not under the DISCUSS (1.1)
>>>>>> c) now refers to vague “other documents” without citation
>>>>>> d) most importantly:
>>>>>> 
>>>>>>   REMOVES a key recommendation that we MAY use frag where it works
>>>>>> 
>>>>>>   Asserts the false claim that IP fragmentation “will fail” in the Internet,
>>>>>>   despite citing evidence that the *majority of the time* it does work
>>>>>>           e.g., for IPv6, sec 3.9
>>>>>> 
>>>>>> What happened? Why is a change this substantial not reflecting the *list consensus*?
>>>>>> 
>>>>>> Joe
>>>>>> 
>>>>>>> On Sep 3, 2019, at 5:59 AM, Alissa Cooper via Datatracker <[e-mail]> wrote:
>>>>>>> 
>>>>>>> Alissa Cooper has entered the following ballot position for
>>>>>>> draft-ietf-intarea-frag-fragile-16: No Objection
>>>>>>> 
>>>>>>> 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://www.ietf.org/iesg/statement/discuss-criteria.html
>>>>>>> for more information about IESG DISCUSS and COMMENT positions.
>>>>>>> 
>>>>>>> 
>>>>>>> The document, along with other ballot positions, can be found here:
>>>>>>> https://datatracker.ietf.org/doc/draft-ietf-intarea-frag-fragile/
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> ----------------------------------------------------------------------
>>>>>>> COMMENT:
>>>>>>> ----------------------------------------------------------------------
>>>>>>> 
>>>>>>> Thanks for addressing my DISCUSS.
>>>>>>> 
>>>>>>> 
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>>>>>> 
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>>> 
>> 
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