Re: [mpls] FW: New Version Notification for draft-jags-mpls-ps-mna-hdr-00.txt

Hi Loa,

We, authors, feel that having a new first Nibble IANA assigned would be a
cleaner solution, but we also like to hear from the other side of the house.

Thanks,
Rakesh


On Fri, Mar 17, 2023 at 3:56 AM Loa Andersson <[email protected]> wrote:

> Rakesh,
>
> Thanks for response, I'd like to point out
>
> - the first nibble is never on its own a sufficient indication for what
>    the payload a a packet is, it might be an Ethernet PW without control
>    word, where the first nibble accidentally is a value that we assigned
>    for some payload.
> - something more is needed to with sufficient accuracy understand what
>    the payload is, for PSD this is the P-bit in the OpCode LSE.
> - actually the the P-bit in the OpCode LSE is sufficient in itself, we
>    don't need the first nibble, unless we for some reason want both
>    brace and waist belt, but I can't see why
> - first nibbles is a scarce resource that should only be allocated if we
>    really need it.
>
> Maybe someone from the the pseudo wire side of the house can confirm this.
>
> /Loa
>
>
> On 2023-03-15 13:16, Rakesh Gandhi wrote:
> > Hi Loa,
> >
> > Authors discussed the first nibble after BOS.
> > Re-using any existing Nibble (e.g. 0000b for CW or 0001b for G-ACH) can
> > lead to backwards compatibility issues on the legacy devices.
> > Note that legacy devices may not support MNA sub-stack.
> > It would be good to assign a new nibble (e.g., 0x2 = 0010b, currently
> > not assigned) to avoid such issues.
> > We can agree on this (i.e. assigning a new nibble for PSD), we can
> > update the draft accordingly.
> >
> > thanks,
> > Rakesh
> >
> >
> >
> >
> > On Fri, Mar 10, 2023 at 9:40 AM Loa Andersson <[email protected]
> > <mailto:[email protected]>> wrote:
> >
> >     All,
> >
> >     I have a question that is not new, and I’m still uncertain what the
> >     correct answer is.
> >
> >     I’m not certain that we should consider “the first nibble” as part
> >     of the MNA PSD. Admittedly it is part of PSD, but not part of the
> >     MNA PSD.
> >
> >     We could say that MNA PSD start after the first nibble. If the
> >     PSD-bit is set in the MNA-label LSE, we can safely ignore the first
> >     nibble, if it is not set we need to look at the first nibble, and
> >     the data following the first nibble is not MNA ancillary data.
> >
> >     I see no meed to define a PSD first nibble. It would also avoid a
> >     potential ambiguity in using the Generic Associated Channel nibble.
> >
> >     For MNA the first should be set to 0000b when sent, and ignored when
> >     received.
> >
> >     /Loa
> >
> >     Sent from my iPhone
> >
> >>     On 10 Mar 2023, at 13:59, Jaganbabu Rajamanickam (jrajaman)
> >>     <[email protected]
> >>     <mailto:[email protected]>> wrote:
> >>
> >>     
> >>
> >>     Hello Everyone,____
> >>
> >>     __ __
> >>
> >>        We like to introduce our new draft on Post-Stack MNA
> solution.____
> >>
> >>        Welcome your review comments and suggestions.____
> >>
> >>     __ __
> >>
> >>     Thanx,____
> >>
> >>     Jags____
> >>
> >>     __ __
> >>
> >>     *From: *[email protected] <mailto:[email protected]>
> >>     <[email protected] <mailto:[email protected]>>
> >>     *Date: *Friday, March 10, 2023 at 7:52 AM
> >>     *To: *Jaganbabu Rajamanickam (jrajaman) <[email protected]
> >>     <mailto:[email protected]>>, Jie Dong <[email protected]
> >>     <mailto:[email protected]>>, Rakesh Gandhi (rgandhi)
> >>     <[email protected] <mailto:[email protected]>>, Royi Zigler
> >>     <[email protected] <mailto:[email protected]>>, Tony
> >>     Li <[email protected] <mailto:[email protected]>>
> >>     *Subject: *New Version Notification for
> >>     draft-jags-mpls-ps-mna-hdr-00.txt____
> >>
> >>
> >>     A new version of I-D, draft-jags-mpls-ps-mna-hdr-00.txt
> >>     has been successfully submitted by Jaganbabu Rajamanickam and
> >>     posted to the
> >>     IETF repository.
> >>
> >>     Name:           draft-jags-mpls-ps-mna-hdr
> >>     Revision:       00
> >>     Title:          Post-Stack MPLS Network Action (MNA) Solution
> >>     Document date:  2023-03-10
> >>     Group:          Individual Submission
> >>     Pages:          17
> >>     URL:
> >>     https://www.ietf.org/archive/id/draft-jags-mpls-ps-mna-hdr-00.txt
> >>     <https://www.ietf.org/archive/id/draft-jags-mpls-ps-mna-hdr-00.txt>
> >>     Status:
> >>     https://datatracker.ietf.org/doc/draft-jags-mpls-ps-mna-hdr/
> >>     <https://datatracker.ietf.org/doc/draft-jags-mpls-ps-mna-hdr/>
> >>     Html:
> >>     https://www.ietf.org/archive/id/draft-jags-mpls-ps-mna-hdr-00.html
> >>     <https://www.ietf.org/archive/id/draft-jags-mpls-ps-mna-hdr-00.html
> >
> >>     Htmlized:
> >>     https://datatracker.ietf.org/doc/html/draft-jags-mpls-ps-mna-hdr
> >>     <https://datatracker.ietf.org/doc/html/draft-jags-mpls-ps-mna-hdr>
> >>
> >>
> >>     Abstract:
> >>        This document defines the Post-Stack MPLS Network Action (MNA)
> >>        solution for carrying Network Actions and Ancillary Data after
> the
> >>        MPLS label stack based on In-Stack MNA solution defined in draft-
> >>        ietf-mpls-mna-hdr.  MPLS Network Actions can be used to influence
> >>        packet forwarding decisions, carry additional OAM information
> >>     in the
> >>        MPLS packet or perform user-defined operations.  This document
> >>        addresses the MNA requirements specified in draft-ietf-mpls-mna-
> >>        requirements.  This document follows the MNA framework specified
> in
> >>        draft-ietf-mpls-mna-fwk.
> >>
> >>
> >>
> >>
> >>     The IETF Secretariat
> >>
> >>     ____
> >>
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> >
> >
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>
> --
> Loa Andersson                        email: [email protected]
> Senior MPLS Expert                          [email protected]
> Bronze Dragon Consulting             phone: +46 739 81 21 64
>

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