Les,

You clearly said:

*> and a given operator might wish to NOT have to configure enablement in
the interest of configuration simplification.*


So let me restate that NO ONE including Bruno nor myself are asking for
making configuration mandatory to *enable* sending of MP-TLVs *and keeping
as default MP-TLV generation disabled. *


The entire topic of contention is about making it mandatory == REQUIRED to
have a knob to *disable* MP-TLV generation (likely on a per TLV basis).


If you take time to read my mail 3rd time perhaps you will find post
helpful ...


Cheers,

R.



On Wed, Sep 25, 2024 at 6:42 PM Les Ginsberg (ginsberg) <[email protected]>
wrote:

> Robert –
>
>
>
> I have read your email twice and it makes no sense to me.
>
>
>
> I stated – and Bruno agreed – that one of the points of discussion was:
>
>
>
> <snip>
>
> Section 7.1
>
> "It is RECOMMENDED that implementations which support the sending of
> MP-TLVs provide configuration controls to enable/disable generation of
> MP-TLVs. "
>
> Possibly changing RECOMMENDED to REQUIRED
>
> <end snip>
>
>
>
> So enabling/disabling MP via configuration is a point of discussion.
>
>
>
> Given that Bruno and I understand each other (even if we do not agree) – I
> do not find your post helpful – just confusing.
>
>
>
>    Les
>
>
>
> *From:* Robert Raszuk <[email protected]>
> *Sent:* Wednesday, September 25, 2024 8:43 AM
> *To:* Les Ginsberg (ginsberg) <[email protected]>
> *Cc:* [email protected]; Tony Li <[email protected]>; Yingzhen Qu <
> [email protected]>; lsr <[email protected]>; lsr-chairs <
> [email protected]>
> *Subject:* Re: [Lsr] Re: WG Last Call for draft-ietf-lsr-multi-tlv
> (7/1/2024 - 7/15/2024)
>
>
>
> Les,
>
>
>
> > Example: One can imagine a network where MP is the norm and a given
> operator
>
> > might wish to NOT have to configure enablement in the interest of
>
> > configuration simplification.
>
>
>
> Wrong example .. or not related to this discussion.
>
>
>
> There is no mandate to enable MP-TLVs by configuration. It can be enabled
> by default and perhaps you can even put this into the text of the draft.
>
>
>
> The discussion is about ALWAYS having ability to disable MP-TLV by
> complient with the draft/rfc implementations.
>
>
>
> Thx,
>
> R
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> On Tue, Sep 24, 2024 at 7:41 AM Les Ginsberg (ginsberg) <ginsberg=
> [email protected]> wrote:
>
> Folks –
>
>
>
> I appreciate the good discussion that went on over the last couple weeks.
>
> There are three potential textual changes being considered:
>
>
>
> Section 4.1
>
>
>
> *"The set of link identifiers SHOULD be identical in all TLVs which are
> part of the MP-TLV set."*
>
>
>
> *Possibly changing "SHOULD" to MUST".*
>
>
>
> Section 7.1
>
>
>
> *"It is RECOMMENDED that implementations which support the sending of
> MP-TLVs provide configuration controls to enable/disable generation of
> MP-TLVs. "*
>
>
>
> *Possibly changing RECOMMENDED to REQUIRED*
>
>
>
> Section 7
>
>
>
> *"Providing appropriate controls to enable/disable the sending of MP-TLVs
> as discussed in Section 7.1 is essential to avoid interoperability issues."*
>
>
>
> *Changing "essential" to "important"*
>
> *Note: This is a consistency issue - if we do NOT use REQUIRED in Section
> 7.1*
>
> *then it would be better NOT to use "essential" in Section 7.*
>
>
>
> DISCUSSION
>
>
>
> Regarding Section 7/7.1
>
>
>
> The argument is being made that using “REQUIRED/essential” reduces the
>
> potential for interoperability problems. This assumes that some vendors who
>
> might otherwise NOT implement the recommended practices would be more
> likely
>
> to do so if normative language were used. This in turn presumes that the
>
> chance of interoperability problems would be reduced as a result.
>
>
>
> I am sympathetic to the goal. Many of us have had real world
>
> experiences with interoperability issues and they are costly.
>
> But I believe mandating aspects of an implementation which are
> unenforceable
>
> and undetectable is not guaranteed to reduce interoperability issues.
>
>
>
> The incidence of interoperability issues is most effectively reduced by
>
> robustness in implementations. As Tony Li has stated:
>
>
>
> *"You do not make the network safer by mandate.  You make it safer by
> writing more forgiving code."*
>
>
>
> What is REQUIRED in a protocol specification are normative statements about
>
> what is sent on the wire. But asserting that there is "one correct way" for
>
> an implementation to support enablement/disablement is not appropriate -
>
> not least because the benefits of a given approach may well depend upon
> the use case.
>
>
>
> Example: One can imagine a network where MP is the norm and a given
> operator
>
> might wish to NOT have to configure enablement in the interest of
>
> configuration simplification. I see no reason why this should be declared
>
> "illegal" just because others might not use that deployment strategy.
>
>
>
> Suggestions/recommendations as to how an implementation might ease
>
> deployment are valuable and these are discussed in the draft - and I
> believe
>
> we do have consensus as to recommended best practices.
>
>
>
> I therefore believe the current wording is appropriate and should not be
>
> changed. The only change that needs to be made to the draft
>
> is to change "essential" to "important" in Section 7 (for consistency).
>
>
>
> I appreciate the passion associated with this discussion - but I am hopeful
>
> that this resolution is acceptable to all.
>
>
>
> Regarding Section 4.1, any interoperability issues with link identifiers
>
> are not introduced by MP. If the WG feels there is an issue here, it should
>
> be taken up outside of MP as it could impact two-way connectivity checks
>
> even in non MP-TLV cases.
>
>
>
> I am not suggesting that such work is necessary - only indicating the
> correct
>
> context in which such work should be done if it is to be done at all.
>
>
>
> As far as the current wording in Section 4.1, it intentionally allows
>
> existing implementations which successfully interoperate sending a subset
>
> of link identifiers to continue to do so.
>
>
>
>    Les
>
>
>
>
>
>
>
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>
>
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