Re: [mpls] WG last call: draft-ietf-mpls-inband-pm-encapsulation

Hi Tony,
thank you for your prompt clarification of the eSPL value allocation. I
assume that the listed implementations, or some of them, are already
deployed. As I understand it, they all use some value as FLI, most likely
the same one across all the implementations. As you've pointed out, using a
value from the Unassigned or Reserved ranges of the Extended
Special-Purpose MPLS Label Values registry
<https://www.iana.org/assignments/mpls-label-values/mpls-label-values.xhtml#extended>
would
be squatting.
About potential squatting (that, as I believe, should not be encouraged).
If I was considering an early implementation of this draft, I'd use a value
from the Experimental range (240-255). If that is the case for this draft,
moving it to the Experimental track, in my opinion, is reasonable. On the
other hand, if the implementers of earlier version of the draft did use a
value from Unassigned range without the early allocation, why wouldn't they
ask for allocation of that specific value rather than letting IANA to pick
one for them and be forced to change their implementations in case the two
values turned to be different?

Regards,
Greg

On Fri, May 3, 2024 at 1:00 PM Tony Li <tony.li@tony.li> wrote:

>
> [WG chair hat: on]
>
> Hi Greg,
>
> I will let the authors respond to the bulk of the comments here, but I do
> want to address some process concerns.
>
> Currently, the registry action for the 'Extended Special-Purpose MPLS
> Label Values' registry is ’Standards Action’. If this document were to be
> published as Experimental, then it would not be allowed to allocate a
> permanent code point, resulting in the implementations squatting on a code
> point. This is sub-optimal.
>
> It appears that there was no early allocation done for a code point, so
> the squatting is already obviously occurring. Also sub-optimal.
>
> First publishing as Standards Track and then shifting to Historical allows
> for code point allocation.
>
> Regards,
> Tony
>
>
> On May 3, 2024, at 12:37 PM, Greg Mirsky <gregimirsky@gmail.com> wrote:
>
> Hi, Tony and All,
> I've read the latest version of the draft. Please find my comments below:
>
>    - The proposed mechanism, as stated in Abstract, applies to "MPLS live
>    traffic". I couldn't find the definition of the term "live traffic" and
>    appreciate it if you can clarify it for me. Does that apply to any MPLS
>    packet or a particular class of MPLS packets in a network?
>    - I appreciate that the document mentions work on Synonymous Flow
>    Labels. However, it is not clear to me why SFL-based application of the AMM
>    is characterized as hop-by-hop, while the solution described in the draft -
>    as edge-to-edge. I would appreciate it if the authors can clarify that
>    characterization of measurement methods, particularly since the T-bit
>    (defined in Figure 1) differentiates between edge-to-edge and hop-by-hop
>    measurements using the proposed solution.
>    - Furthermore, it seems like the comparison of the impact on an MPLS
>    packet of the proposed solution and IOAM is inaccurate. As I understand it,
>    contrary to the statement in Introduction that "the former doesn't
>    introduce any new header whereas the latter introduces a new In-situ OAM
>    header", both introduce (unlike SFL-based application of AMM) extra
>    ancillary data in an MPLS packet.
>    - And, on the last paragraph in Introduction. I believe that
>    publishing a draft on Standard track and then moving it to Historic once
>    another solution is standardized by IETF is sub-optimal. I recognize the
>    value of the work put in by implementers of the described in the draft
>    solution. The deployment experience is invaluable. On the other hand, there
>    seems to be an agreement that the MNA is the preferred mechanism to support
>    AMM in the MPLS networks. (Note that draft-ietf-mpls-mna-usecases is being
>    updated to include AMM as another use cases of on-path telemetry in the
>    MPLS networks, in addition of IOAM). Hence my proposal to switch this
>    document to Experimental track (see my question about the requested IANA
>    allocation below).
>    - The list of implementations is impressive and suggests that there
>    are several deployments. If that is the case, which value of eSPL for
>    Flow-ID Label Indicator is used?
>
> In conclusion, I don't support progressing this draft on the Standard
> track. I would support progressing it as Experimental or Informational
> (perhaps that means that the IANA section is removed).
>
> Regards,
> Greg
>
> On Thu, Apr 25, 2024 at 8:09 AM Tony Li <tony.li@tony.li> wrote:
>
>>
>> [WG chair hat: on]
>>
>>
>> Hi all,
>>
>> This starts a 2 week working group last call on
>> draft-ietf-mpls-inband-pm-encapsulation.
>>
>> This last call ends at 12:01 PM PDT, Thurs. May 9, 2024.
>>
>> Please send all comments to the mailing list.
>>
>> Regards,
>> Tony
>>
>>
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>
>