Re: Errata #5933 for RFC8200

[Fernando Gont <[e-mail]>]

On 27/2/20 18:32, Suresh Krishnan wrote:
> Hi Fernando,
> 
>> On Feb 27, 2020, at 3:07 PM, Fernando Gont <[e-mail] 
>> <mailto:[e-mail]>> wrote:
>>
>> Suresh,
>>
>> Two months ago I filled an errata on RFC8200 regarding the processing 
>> of IPv6 extension headers. The errata is available here: 
>> https://www.rfc-editor.org/errata/eid5933
>>
>> While I believe that folks with a knowledge of Internet Protocols 
>> would be able to interpret what is in RFC8200, given recent 
>> discussions on the topic, and upon a re-read of the text, I believe a 
>> clarification is warranted, such that we allow all sorts of curious 
>> interpretations of the text.
> 
> I think this would be fine to clarify, but IMHO the errata process is 
> not the right way to do it.
> 
> Based on the IESG Statement about processing of RFC Errata for the 
> IETF Stream 
> (https://ietf.org/about/groups/iesg/statements/processing-rfc-errata/)
> 
> "Changes that modify the working of a protocol to something that might 
> be different from the intended consensus when the document was approved 
> should be either Hold for Document Update or Rejected. Deciding between 
> these two depends on judgment. Changes that are clearly modifications to 
> the intended consensus, or involve large textual changes, should be 
> Rejected."

I have been part of the rfc2460bis/RFC8200 effort, and clearly the 
consensus was the IPv6 extension headers are not added/removed along the 
packet delivery path.

For instance, Appendix B of RFC8200 says:
    o  Clarified that extension headers (except for the Hop-by-Hop
       Options header) are not processed, inserted, or deleted by any
       node along a packet's delivery path.



> As you said above, some people might interpret the text in RFC8200 to 
> mean the replacement text you provided in the errata but others might 
> read the text exactly as written ("until the packet reaches the node 
> identified in the Destination Address field of the IPv6 header”). Given 
> that the text in RFC8200 had consensus (and I don’t think you said 
> otherwise) and it is impossible to tell after the fact if the proposed 
> replacement text would have achieved consensus, I think this erratum 
> falls under the above category.

Can you please, as AD, answer these questions:

* Does IPv6 support IPv6 header insertion/removal along the packet 
delivery path?

* If you assume so, then, How does it play with core IPv6 functionality 
like:
     IPsec AH
     PMTUD
     error reporting



> I will process this and move it to the “Hold for Document Update” state 
> with the following note

This would clearly be incorrect. This is not a proposal for new 
behavior, but a clarification of the intended behavior of IPV6/RFC8200.

Thanks,
-- 
Fernando Gont
SI6 Networks
e-mail: [e-mail]
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