Re: [mpls] Last Call: <draft-ietf-mpls-spl-terminology-03.txt> (Special Purpose Label terminology) to Informational RFC

[Kireeti Kompella <[e-mail]>]

Thanks, Tom, for your feedback.

The two ranges (0-15, 16-1048575) have the unfortunate property of being contiguous and thus appearing related, but they are completely unrelated: one is for solo labels, the other is for the second label of a composite special purpose label.  This unintended confluence may be aggravated by referring to the ranges are "lower" and "upper".  I would get rid of these terms as follows:

NEW
     o  Collectively, the two (unrelated) ranges (0-15 and 16-1048575) are
          known as Special Purpose Labels (SPL).

     o  Special purpose labels from the range 0-15 are
         called Base Special Purpose Labels (bSPL).

     o  Special purpose labels from the range 16-1048575
          are called Extended Special Purpose Labels (eSPL).  The
          reserved values 0-15 from the 'Extended Special-Purpose MPLS
          Label Values' registry do not need a name as they are not available
          for allocation.
END

(change of tense, as readers of the RFC will be seeing a fait accompli.)

Kireeti.

On 8/24/20, 03:02, "tom petch" <[e-mail]> wrote:

    [External Email. Be cautious of content]


    On 23/08/2020 21:47, Adrian Farrel wrote:
    > Hi Tom,
    >
    > You're right (a condition that must be scarily familiar for you).
    >
    > Probably...
    >
    > OLD
    >     o  Collectively, the two ranges are known as Special Purpose Labels
    >        (SPL).
    >
    >     o  The special purpose labels from the lower range will be called
    >        Base Special Purpose Labels (bSPL).
    >
    >     o  The special purpose labels from the higher range will be called
    >        Extended Special Purpose Labels (eSPL).
    > NEW
    >     o  Collectively, the two ranges (0-15, and 16-1048575) are known
    >         as Special Purpose Labels (SPL).
    >
    >     o  The special purpose labels from the lower range (0-15) will be
    >         called Base Special Purpose Labels (bSPL).
    >
    >     o  The special purpose labels from the higher range (16-1048575)
    >          will be called Extended Special Purpose Labels (eSPL).  The
    >          reserved values 0-15 from the 'Extended Special-Purpose MPLS
    >          Label Values' registry do not need a name as they can never be
    >          used.
    > END

    Yes, clearer.

    Perhaps
    "       The
         reserved values 0-15 from the 'Extended Special-Purpose MPLS
         Label Values' registry do not need a name as they are not available
    for allocation. "
    to tie in with the wording of IANA.  They SHOULD NOT or MUST NOT be used
    but I can see some independent-minded organisation deciding that because
    noone else will ever use them then they can and they will so I think
    'can never be used' is not quite right.  They can never be allocated so
    we do not need an identifier for them, which is what I am wanting to
    express.

    I note that this is Informational and so RFC2119 language is best avoided.

    Tom Petch

    > Best,
    > Adrian
    >
    > -----Original Message-----
    > From: tom petch <[e-mail]>
    > Sent: 19 August 2020 17:25
    > To: [e-mail]
    > Cc: [e-mail]; [e-mail]; [e-mail];
    > [e-mail]
    > Subject: Re: Last Call: <draft-ietf-mpls-spl-terminology-03.txt> (Special
    > Purpose Label terminology) to Informational RFC
    >
    > I find this confusing.
    >
    > It specifies two ranges 0-15 and 0-1048575 the latter being subdivided
    > into ranges 0-15 16-239 etc and then talks of the lower range and the
    > higher range; is the higher range 0-1048575 or 16-239 or 16-1048575 or ...?
    > Lesser and greater or first and second or smaller and larger .. I might
    > find unambiguous but reading this with an innocent eye, I find higher
    > ambiguous.
    >
    > And in Security, 'It does not effect the forwarding ...' Well, no, it
    > would likely not affect it either:-)
    >
    > Tom Petch
    >
    >
    >
    > On 12/08/2020 19:48, The IESG wrote:
    >>
    >> The IESG has received a request from the Multiprotocol Label Switching WG
    >> (mpls) to consider the following document: - 'Special Purpose Label
    >> terminology'
    >>     <draft-ietf-mpls-spl-terminology-03.txt> as Informational RFC
    >>


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