Re: [mpls] [Technical Errata Reported] RFC5960 (2533)

  Speaking as an author, my view is that the original text is correct, 
and the correction is not needed.

It's a fundamental of the IP protocol suite (which includes MPLS) that 
the parser knows what protocol to expect from the previous header or if 
there is no previous header from an identifier in the lower layer.

Indeed the "correction" makes an additional statement, but I don't think 
that is needed because it's an implication of the existing text.

- Stewart

On 30/09/2010 01:18, Benjamin Niven-Jenkins wrote:
> While the intent of reported errata is technically correct I'm somewhat torn between whether I think it should be rejected, or whether I don't care.
>
> My thinking is:
>
> The errata is technically correct because a corner case does exist where a section layer that doesn't support higher layer protocol multiplexing can still be used to support MPLS-TP in some scenarios.
>
> I don't like the proposed replacement text because the original text is placing a requirement on the section layer technology and I think it is reasonable to say "if you want your section layer to work with MPLS-TP it MUST do/support X", however I don't think it's reasonable to say "if you want your section layer to work with MPLS-TP it MAY have to do X" (which is essentially the change the proposed text makes) because it leaves it unclear as to what is actually required from the section layer which practically reduces to section layers having to support X anyway so it becomes a (implicit) MUST in any case.
>
> Furthermore the original text only states that a section layer MUST have a means of identifying the type of payload. If a section layer does not support multiplexing then it has an implicit means of identifying the payload by the interface over which the payload arrived and therefore it meets the requirement as stated by the original text.
>
> Ben
>
>
> On 29 Sep 2010, at 18:39, RFC Errata System wrote:
>
>> The following errata report has been submitted for RFC5960,
>> "MPLS Transport Profile Data Plane Architecture".
>>
>> --------------------------------------
>> You may review the report below and at:
>> http://www.rfc-editor.org/errata_search.php?rfc=5960&eid=2533
>>
>> --------------------------------------
>> Type: Technical
>> Reported by: Italo Busi<italo.busi@alcatel-lucent.com>
>>
>> Section: 3.2
>>
>> Original Text
>> -------------
>>    A section MUST provide a means of identifying the type of payload it
>>    carries.
>>
>> Corrected Text
>> --------------
>>    A section MAY be required to provide a mechanism for multiplexing MPLS
>>    with other protocols.
>>
>>
>> Notes
>> -----
>> This change is intended to clarify that providing a multiplexing capability for a section layer is optional.
>>
>> See https://datatracker.ietf.org/liaison/916/
>>
>> Instructions:
>> -------------
>> This errata is currently posted as "Reported". If necessary, please
>> use "Reply All" to discuss whether it should be verified or
>> rejected. When a decision is reached, the verifying party (IESG)
>> can log in to change the status and edit the report, if necessary.
>>
>> --------------------------------------
>> RFC5960 (draft-ietf-mpls-tp-data-plane-04)
>> --------------------------------------
>> Title               : MPLS Transport Profile Data Plane Architecture
>> Publication Date    : August 2010
>> Author(s)           : D. Frost, Ed., S. Bryant, Ed., M. Bocci, Ed.
>> Category            : PROPOSED STANDARD
>> Source              : Multiprotocol Label Switching
>> Area                : Routing
>> Stream              : IETF
>> Verifying Party     : IESG
>> _______________________________________________
>> mpls mailing list
>> mpls@ietf.org
>> https://www.ietf.org/mailman/listinfo/mpls
>

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