Ron - Dealing simply with the language in the RFCs, both RFCs discuss the problems the RFCs are aimed at solving in the Introduction. Those problems are not specific to the set of link attributes defined at the time of writing the RFCs. Which is why the Introduction concludes with:
"...as evolution of use cases for link attributes can be expected to continue in the years to come, this document defines a solution that is easily extensible to the introduction of new applications and new use cases." Which is exactly what is being introduced in draft-ietf-lsr-flex-algo-bw-con. There is then the more important question as to why new attributes - and Generic Metric specifically - should NOT follow the ASLA model. The same issues discussed in the RFCs that motivated the ASLA solution certainly apply to Generic Metric. This has been made clear by others in their responses to this thread - and each of the arguments Shraddha has made have been countered by responses in this thread. The substance of what is being discussed here is not (and should not be) whether there is a violation of the "letter of the law" - but whether there is a behavioral aspect of the new attribute that makes ASLA unsuitable. On that point I think clear and cogent arguments have been made that ASLA is appropriate and necessary. If the WG feels that more explicit language is needed to prevent such debates in the future, I am happy to work on an Errata - but that isn’t the substance of this discussion and I would much prefer that any future posts on this thread focus on the substantive issues. We can address improving the RFC language separately. Les > -----Original Message----- > From: Ron Bonica <rbonica=40juniper....@dmarc.ietf.org> > Sent: Thursday, July 22, 2021 9:13 PM > To: Les Ginsberg (ginsberg) <ginsb...@cisco.com>; Acee Lindem (acee) > <a...@cisco.com>; Shraddha Hegde <shrad...@juniper.net>; > gregory.mir...@ztetx.com; Peter Psenak (ppsenak) <ppse...@cisco.com>; > lsr@ietf.org > Cc: draft-ietf-lsr-flex-algo-bw-con.auth...@ietf.org > Subject: RE: [Lsr] I-D Action: draft-ietf-lsr-flex-algo-bw-con-01.txt > > Les, > > Please, let us avoid discussion of whether my message is disingenuous. As > Acee will agree, discussion of my internal motivations and moral deficiencies > is beyond the scope of the LSR WG. > > Now, let us address my point and your counter points. My point was that > draft-ietf-lsr-flex-algo-bw-con does not violate RFC 8919. Nothing more, > nothing less. > > In your counterpoint #1, you point out tension between draft-ietf-lsr-flex- > algo-bw-con and draft-ietf-lsr-flex-algo. While this point deserves > discussion, > it is orthogonal to my point. It is entirely possible that both of the > following > statements are true: > > - draft-ietf-lsr-flex-algo-bw-con does not violate RFC 8919 > - there is tension between draft-ietf-lsr-flex-algo-bw-con and draft-ietf-lsr- > flex-algo > > In your counterpoint #2, you talk about the "clear intent" of RFC 8919. > Section 6.1 of RFC 8919 reduces that intent to a few very clear normative > statements. Draft-ietf-lsr-flex-algo-bw-con does not violate any of those > normative statements. Therefore, it does not violate RFC 8919. > > You may say: > > - Section 6.1 should have included more prohibitions > - The authors had additional prohibitions in mind when they wrote the draft, > but failed to add them to Section 6.1 > > That's all fine, but the community agreed only to the words on the page, not > the authors larger intent. > > > Ron > > > > > > Juniper Business Use Only > > -----Original Message----- > From: Les Ginsberg (ginsberg) <ginsberg=40cisco....@dmarc.ietf.org> > Sent: Thursday, July 22, 2021 2:49 PM > To: Ron Bonica <rbon...@juniper.net>; Acee Lindem (acee) > <a...@cisco.com>; Shraddha Hegde <shrad...@juniper.net>; > gregory.mir...@ztetx.com; Peter Psenak (ppsenak) <ppse...@cisco.com>; > lsr@ietf.org > Cc: draft-ietf-lsr-flex-algo-bw-con.auth...@ietf.org > Subject: RE: [Lsr] I-D Action: draft-ietf-lsr-flex-algo-bw-con-01.txt > > [External Email. Be cautious of content] > > > Ron - > > With respect, it is hard to read your email without feeling that it is > disingenuous. > > But, let's cover the relevant points nonetheless. > > Point #1: > > https://urldefense.com/v3/__https://datatracker.ietf.org/doc/html/draft- > ietf-lsr-flex-algo-17*section-12__;Iw!!NEt6yMaO-gk!XOCcoj- > YdMkhznRiGAo1oeY1A6HMHuk5BDmsYqHAUf_hYgKb9tlp_Umpu3UxZFFM$ > states: > > " Link attribute advertisements that are to be used during Flex- > Algorithm calculation MUST use the Application-Specific Link > Attribute (ASLA) advertisements defined in [RFC8919] or [RFC8920]..." > > As the new generic-metric is intended for use by flex-algo it needs to > conform to this normative statement. > > Point #2: > > RFC 8919 and 8920 were written to address ambiguities associated with the > use of multiple applications. > The Introduction sections of both documents discuss this in some detail. > > The clear intent is to make use of ASLA going forward - not to restrict ASLA > only to the set of link attributes defined at the time of the writing of the > RFCs. Failure to do so would reintroduce the same set of issues that RFC > 8919/8920 were written to address. > Your attempt to infer that because Generic-Metric was not defined at the > time that RFC 8919/8920 were written that the RFCs don’t apply to it makes > no sense. > ASLA is in fact a revision to the link attribute architecture and is meant to > be > used going forward. > > The more appropriate question to ask is why we need to define a legacy style > sub-TLV for new link attributes? Ketan has made this point in his post on this > thread and I have sympathy with his position. > > We do understand that legacy applications such as RSVP-TE may continue to > be deployed in networks for some time to come. It is not reasonable to > expect that legacy application implementations will be updated to use ASLA, > which is why I do not object to defining a legacy style encoding for Generic > Metric if folks believe that legacy applications may be enhanced to support > new link attributes. > > I strongly disagree with your interpretation that ASLA is limited only to the > code points defined in RFC 8919/8920. > > Les > > > > -----Original Message----- > > From: Ron Bonica <rbonica=40juniper....@dmarc.ietf.org> > > Sent: Thursday, July 22, 2021 10:28 AM > > To: Acee Lindem (acee) <a...@cisco.com>; Les Ginsberg (ginsberg) > > <ginsb...@cisco.com>; Shraddha Hegde <shrad...@juniper.net>; > > gregory.mir...@ztetx.com; Peter Psenak (ppsenak) > <ppse...@cisco.com>; > > lsr@ietf.org > > Cc: draft-ietf-lsr-flex-algo-bw-con.auth...@ietf.org > > Subject: RE: [Lsr] I-D Action: draft-ietf-lsr-flex-algo-bw-con-01.txt > > > > Acee, > > > > I don't think that draft-ietf-lsr-flex-algo-bw-con violates RFC 8919. > > > > Section 6.1 of RFC 8919 says: > > > > " New applications that future documents define to make use of the > > advertisements defined in this document MUST NOT make use of legacy > > advertisements. This simplifies deployment of new applications by > > eliminating the need to support multiple ways to advertise attributes > > for the new applications." > > > > Section 3 of RFC 8919 defines legacy advertisements. The definition of > > legacy advertisements does not include new attributes such as generic > > metric. Therefore draft-ietf-lsr-flex-algo-bw-con does not violate RFC > > 8919 > > > > Relevant text from Section 3 of RFC 8919 is included below for > convenience. > > > > > > Ron > > > > > > RFC 8919, Section 3 > > --------------------------- > > 3. Legacy Advertisements > > > > > > Existing advertisements used in support of RSVP-TE include sub-TLVs > > for TLVs 22, 23, 25, 141, 222, and 223 and TLVs for Shared Risk Link > > Group (SRLG) advertisement. > > > > Sub-TLV values are defined in the "Sub-TLVs for TLVs 22, 23, 25, 141, > > 222, and 223" registry. > > > > TLVs are defined in the "TLV Codepoints Registry". > > > > 3.1. Legacy Sub-TLVs > > > > +======+====================================+ > > | Type | Description | > > +======+====================================+ > > | 3 | Administrative group (color) | > > +------+------------------------------------+ > > | 9 | Maximum link bandwidth | > > +------+------------------------------------+ > > | 10 | Maximum reservable link bandwidth | > > +------+------------------------------------+ > > | 11 | Unreserved bandwidth | > > +------+------------------------------------+ > > | 14 | Extended Administrative Group | > > +------+------------------------------------+ > > | 18 | TE Default Metric | > > +------+------------------------------------+ > > | 33 | Unidirectional Link Delay | > > +------+------------------------------------+ > > | 34 | Min/Max Unidirectional Link Delay | > > +------+------------------------------------+ > > | 35 | Unidirectional Delay Variation | > > +------+------------------------------------+ > > | 36 | Unidirectional Link Loss | > > +------+------------------------------------+ > > | 37 | Unidirectional Residual Bandwidth | > > +------+------------------------------------+ > > | 38 | Unidirectional Available Bandwidth | > > +------+------------------------------------+ > > | 39 | Unidirectional Utilized Bandwidth | > > +------+------------------------------------+ > > > > Table 1: Sub-TLVs for TLVs 22, 23, 25, > > 141, 222, and 223 > > > > > > > > Juniper Business Use Only > > > > -----Original Message----- > > From: Lsr <lsr-boun...@ietf.org> On Behalf Of Acee Lindem (acee) > > Sent: Tuesday, July 20, 2021 1:21 PM > > To: Les Ginsberg (ginsberg) <ginsberg=40cisco....@dmarc.ietf.org>; > > Shraddha Hegde <shrad...@juniper.net>; gregory.mir...@ztetx.com; > > ppsenak=40cisco....@dmarc.ietf.org; lsr@ietf.org > > Cc: draft-ietf-lsr-flex-algo-bw-con.auth...@ietf.org > > Subject: Re: [Lsr] I-D Action: draft-ietf-lsr-flex-algo-bw-con-01.txt > > > > [External Email. Be cautious of content] > > > > > > Speaking as WG member: > > > > I agree with Les. The Generic Metric MUST be advertised as an ASLA for > > usage in Flex Algorithm. Additionally, it may be advertised as a > > sub-TLV in IS- IS link TLVs. However, the latter encoding really > > shouldn't be used for new applications (at least that is my reading of RFC > 8919). > > > > For OSPF, I'd certainly hope one wouldn't originate additional LSAs > > when an ASLA can support the legacy applications with the ASLA mask. > > > > Thanks, > > Acee > > > > _______________________________________________ Lsr mailing list Lsr@ietf.org https://www.ietf.org/mailman/listinfo/lsr
