Thanks a lot Ron. I will craft some explanatory text to add to Section 5 
and get back to you in a day or two.

Regards
Suresh

On 09/10/2015 12:48 PM, Ronald Bonica wrote:
>
> Resend, this time with correct email address
>
>
>> -----Original Message-----
>> From: Ronald Bonica
>> Sent: Wednesday, September 09, 2015 4:50 PM
>> To: 'Suresh Krishnan' <[email protected]>; [email protected]
>> Cc: [email protected]
>> Subject: RE: [Gen-art] Gen-ART review of draft-ietf-conex-tcp-modifications
>>
>> Suresh,
>>
>> You are absolutely right. We have two possible solutions, an HBH Option and
>> a Destination Option.  Both solutions severely limit CONEX deployability.
>>
>> Since my comment is more about draft-ietf-conex-destopt than it is about
>> draft-ietf-conex-tcp-modifications, I think that we can let draft-ietf-conex-
>> tcp-modifications go forward, as is.
>>
>> Before draft-ietf-conex-tcp-modifications comes up for last call, we might
>> want to augment Section 5, explaining why both solutions limit severely limit
>> CONEX deployability. Since all of the CONEX documents are EXPERIMENTAL,
>> that caveat shouldn't be an impediment to publication.
>>
>> We will need to address the problem before the CONEX documents become
>> PROPOSED STANDARD. But we can cross that bridge when we get to it.
>>
>>                                                                              
>>           Ron
>>
>>
>>
>>
>>> -----Original Message-----
>>> From: Suresh Krishnan [mailto:[email protected]]
>>> Sent: Tuesday, September 08, 2015 2:47 PM
>>> To: Ronald Bonica <[email protected]>; [email protected]
>>> Cc: [email protected]
>>> Subject: Re: [Gen-art] Gen-ART review of
>>> draft-ietf-conex-tcp-modifications
>>>
>>> Hi Ron,
>>>     Thanks for your review. Please find comments inline.
>>>
>>> On 09/08/2015 12:20 PM, Ronald Bonica wrote:
>>>> I am the assigned Gen-ART reviewer for this draft. For background on
>>>> Gen-ART, please see the FAQ at
>>>> <http://wiki.tools.ietf.org/area/gen/trac/wiki/GenArtfaq>
>>>>
>>>> Document:                                      
>>>> draft-ietf-conex-tcp-modifications-09
>>>> Reviewer:                                        Ron Bonica
>>>> Review Date:                                  2015-09-07
>>>> IETF LC End Date:                          2015-08-31
>>>> IETF Telechat Date:                      2015-10-01
>>>>
>>>> Summary:          This document will be ready for publication as soon as 
>>>> the
>>> major issue (below) below is addressed.
>>>>
>>>> Major Issues:
>>>>
>>>> This document contains a normative reference to
>>>> draft-ietf-conex-destopt-
>>> 09. The normative reference is appropriate, because this document
>>> doesn't work at all unless the concepts described in
>>> draft-ietf-conex-destopt-09 work.
>>>>
>>>> I am concerned about draft-ietf-conex-destopt-09. It uses an IPv6
>>> Destination Option to signal CONEX state to intermediate routers.
>>> However, according to RFC 2460:
>>>>
>>>>      "With one exception, extension headers are not examined or
>> processed
>>>>      by any node along a packet's delivery path, until the packet reaches
>>>>      the node (or each of the set of nodes, in the case of multicast)
>>>>      identified in the Destination Address field of the IPv6 header."
>>>>
>>>> The exception to which RFC 2460 refers is the Hop-by-hop Extension
>>> Header. Intermediate routers don't examine Destination Options.
>>>>
>>>> Section 5 of draft-ietf-conex-destopt-09 attempts to address this
>>>> issue, but
>>> I am not sure that the argument is acceptable.
>>>
>>> I think we can discuss this further but in my view there are no good
>>> solutions to this problem. There are two probable alternatives here
>>>
>>> Hop-by-hop options: This is arguably the right way to define
>>> information that is inspected on intermediate nodes. But using this
>>> implies that there is a huge performance penalty for conex packets
>>> that hit conex unaware routers (basically being punted into the slow
>>> path in the best case, being dropped at worst). RFC7045 section 2.2
>>> talks about this explicitly but this problem has been known for much
>> longer. This will break requirement R-3.
>>>
>>> Destination options: Intended for the destination of the packet, but
>>> capable of being read at *consenting* conex-aware network nodes. Does
>>> not affect nodes that are conex unaware. This is no different than a
>>> router that looks at a TCP port for an enforcing an ACL, right?
>>>
>>> Let me know what you think. (Especially, we would be grateful if you
>>> think there is a better solution we ought to be considering that would
>>> meet the
>>> requirements)
>>>
>>> Regards
>>> Suresh
>>>
>
>


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