Thanks Les - I just wanted to make sure that the text added in -09 with respect to link metric on interface groups addressed your comment.
Thanks, Acee > On Apr 26, 2024, at 13:54, Les Ginsberg (ginsberg) > <ginsberg=40cisco....@dmarc.ietf.org> wrote: > > Acee – > > I left it up to Shraddha to introduce the I-bit or not – she has chosen not > to do so. > I believe all of my comments have been addressed to my satisfaction – sorry > if it appeared that I left this issue unresolved. > > Les > > From: Acee Lindem <acee.lin...@gmail.com> > Sent: Friday, April 26, 2024 8:53 AM > To: Shraddha Hegde <shraddha=40juniper....@dmarc.ietf.org> > Cc: Ketan Talaulikar <ketant.i...@gmail.com>; lsr <lsr@ietf.org>; > draft-ietf-lsr-flex-algo-bw-...@ietf.org; Les Ginsberg (ginsberg) > <ginsb...@cisco.com> > Subject: Re: [Lsr] Working Group Last Call for "Flexible Algorithms: > Bandwidth, Delay, Metrics and Constraints" - > draft-ietf-lsr-flex-algo-bw-con-07 > > Hi Ketan, Shraddha and Les, > > > I’m trying to conclude this thread and send this document to the AD. I’ve > read the Emails but I must admit I don’t understand all the arguments. > > > Ketan - if we have the generic-metric in IS-IS, why wouldn’t define it in > OSPF as well? If you cannot provide a compelling argument, I ‘m going to > request publication of the document send it to the actual LSR AD. > > Shraddha - I see that you included similar text in section 4.3.1 to address > Les’s comment. I guess the example referring to Flex algo 128/129 is not > needed. > > Les - I’m sure what the I-bit but I don’t see that adding it at this juncture > is a good idea unless the described protocol enhancements don’t work without > it. > > Thanks, > Acee > > > > > On Apr 15, 2024, at 02:46, Shraddha Hegde > <shraddha=40juniper....@dmarc.ietf.org > <mailto:shraddha=40juniper....@dmarc.ietf.org>> wrote: > > Hi Ketan, > > Thanks for reply. > Pls see inline.. > > > Juniper Business Use Only > > From: Ketan Talaulikar <ketant.i...@gmail.com <mailto:ketant.i...@gmail.com>> > Sent: Monday, April 8, 2024 2:25 PM > To: Shraddha Hegde <shrad...@juniper.net <mailto:shrad...@juniper.net>> > Cc: Acee Lindem <acee.lin...@gmail.com <mailto:acee.lin...@gmail.com>>; lsr > <lsr@ietf.org <mailto:lsr@ietf.org>>; > draft-ietf-lsr-flex-algo-bw-...@ietf.org > <mailto:draft-ietf-lsr-flex-algo-bw-...@ietf.org> > Subject: Re: [Lsr] Working Group Last Call for "Flexible Algorithms: > Bandwidth, Delay, Metrics and Constraints" - > draft-ietf-lsr-flex-algo-bw-con-07 > > [External Email. Be cautious of content] > > Hi Shraddha, > > Thanks for your responses. Please check inline below for clarifications with > KT. > > > On Thu, Apr 4, 2024 at 9:49 AM Shraddha Hegde <shrad...@juniper.net > <mailto:shrad...@juniper.net>> wrote: > Hi Ketan, > > Thanks for the review and comments. > Pls see inline for replies. > > > Juniper Business Use Only > > From: Ketan Talaulikar <ketant.i...@gmail.com <mailto:ketant.i...@gmail.com>> > Sent: Thursday, March 21, 2024 10:07 PM > To: Acee Lindem <acee.lin...@gmail.com <mailto:acee.lin...@gmail.com>> > Cc: lsr <lsr@ietf.org <mailto:lsr@ietf.org>>; > draft-ietf-lsr-flex-algo-bw-...@ietf.org > <mailto:draft-ietf-lsr-flex-algo-bw-...@ietf.org> > Subject: Re: [Lsr] Working Group Last Call for "Flexible Algorithms: > Bandwidth, Delay, Metrics and Constraints" - > draft-ietf-lsr-flex-algo-bw-con-07 > > [External Email. Be cautious of content] > > Hi All, > > I have reviewed this document and believe it needs some further work before > publication. > > I am sharing my comments below: > > 1) There is the following text in sec 2.1 and 2.2 for Generic Metric. > > A metric value of 0xFFFFFF is considered as maximum link metric and a link > having this metric value MUST NOT be used during Flex-algorithm calculations > [RFC9350 > <https://urldefense.com/v3/__https:/www.ietf.org/archive/id/draft-ietf-lsr-flex-algo-bw-con-08.html*RFC9350__;Iw!!NEt6yMaO-gk!DwOojW2YZ48IROz9qMyyh7uKj3rYC-09avEhFQtcPkvxJ5mKF5Cyy6qSVvDJ89s9DmAUVwsT_pgfmuk-veyTXw$>]. > The link with maximum generic metric value is not available for the use of > Flexible Algorithms but is availble for other use cases. > > I believe the FlexAlgo reference here is to > https://www.rfc-editor.org/rfc/rfc9350.html#name-max-metric-consideration > <https://urldefense.com/v3/__https:/www.rfc-editor.org/rfc/rfc9350.html*name-max-metric-consideration__;Iw!!NEt6yMaO-gk!DwOojW2YZ48IROz9qMyyh7uKj3rYC-09avEhFQtcPkvxJ5mKF5Cyy6qSVvDJ89s9DmAUVwsT_pgfmumv0_0Zeg$> > > > But the above text does not align with the RFC9350. If a link is to be made > unavailable for FlexAlgos operating with a specific Generic Metric, then the > way to do that is to omit that specific Generic Metric TLV from the ASLA for > flex-algo application. The same would apply for other applications - just > omit the metric. Why do we need a special MAX-LINK-METRIC value for generic > metric given that it is a new thing we are introducing? > > <SH> I see what you are saying. Text is updated as below for ISIS and similar > for OSPF. > “A metric value of > 0xFFFFFF is considered as maximum link metric and a link having > this metric value MUST be used during Flex-algorithm calculations > as a last resort link as described in sec 15.3 of RFC[9350] > > KT> Thanks - that works. Perhaps also clarify that to make the link unusable > by FlexAlgo using that generic metric, the advertisement of the particular > generic metric can be skipped. > <SH2> ok > > > 2) This comment is specific to OSPF given the encoding differences it has > with ISIS. Section 2.2 allows for Generic Metric TLV to be used in too many > places without clear specification of what it is used for - this is a > potential pitfall for interop issues. RFC9492 provides helpful directions for > us here. > a) This draft specifies FlexAlgo extensions, it is natural that Generic > Metric be advertised under ASLA TLV. No issues here. > b) This draft does not specify anything about use of generic metric in base > OSPF and as a reminder there is nothing like L-bit in OSPF encoding. > Therefore, it does not make sense to advertise Generic Metric outside of ASLA > and under the OSPFv2 Extended Link TLV or OSPFv3 Router Link TLV. > c) This draft does not specify anything about use of generic metric with > RSVP-TE/GMPLS. Therefore, it does not make sense to advertise Generic Metric > in the TE Opaque LSAs. > We can have specific documents that introduce (b) or (c) when there is a > proper specification. > <SH> Generic metric is a link attribute and can be used by other applications > apart from Flex-algo. > I don’t see a reason to not take code-points under other applicable LSAs. > > KT> I disagree on this one. There is a reason why what is proposed in the > draft for ISIS is OK - due to the L-bit in ASLA, we need codepoints both > under ASLA and at the top level for FlexAlgo. There is no L-bit in OSPF and > therefore this does not apply. The code-points can be allocated when the > behavior is specified for those other LSAs and applications (beyond FlexAlgo) > in OSPF. We should not set the precedent for allocating code-points for TLVs > without any defined use or behavior. > > <SH2> Early code points are taken and implementations underway for other > applications. > > “Implementations MUST support sending and receiving generic metric > sub-TLV in ASLA encodings as well as in the TLV 22/extended link LSA/TE-LSAs. > The usage of a generic metric by an individual application is subject to the > same > rules that apply to other link attributes defined in respective standards.” > > The above text clarifies the use of generic metric by individual application. > > 3) Please introduce a reserved field to pad the OSPF FAEMD sub-TLV to a 4 > octet boundary as is the convention in OSPF - > https://www.ietf.org/archive/id/draft-ietf-lsr-flex-algo-bw-con-08.html#section-3.2.2 > > <https://urldefense.com/v3/__https:/www.ietf.org/archive/id/draft-ietf-lsr-flex-algo-bw-con-08.html*section-3.2.2__;Iw!!NEt6yMaO-gk!DwOojW2YZ48IROz9qMyyh7uKj3rYC-09avEhFQtcPkvxJ5mKF5Cyy6qSVvDJ89s9DmAUVwsT_pgfmunYcymQgw$> > <SH> OK > > KT> Thanks. > > > 4) In section 3.2.2 there is the following text for OSPF. Could you please > use the TLV/sub-TLV name? OSPF folks are not good at remembering numbers ;-) > > The Min Unidirectional Link Delay as advertised by sub-sub-TLV 12 of ASLA > sub-TLV [RFC8920 > <https://urldefense.com/v3/__https:/www.ietf.org/archive/id/draft-ietf-lsr-flex-algo-bw-con-08.html*RFC8920__;Iw!!NEt6yMaO-gk!DwOojW2YZ48IROz9qMyyh7uKj3rYC-09avEhFQtcPkvxJ5mKF5Cyy6qSVvDJ89s9DmAUVwsT_pgfmun5uDKc7A$>], > MUST be compared against the Maximum delay advertised in the FAEMD sub-TLV. > <SH> changed to “The Unidirectional Link Delay as advertised by sub-sub-TLV > 12” > > KT> Perhaps my comment was not clear. The following text would be more > accurate: > > The Min Delay value advertised via the Min/Max Unidirectional Link Delay > sub-TLV [RFC7471] of the ASLA sub-TLV [RFC8920 > <https://urldefense.com/v3/__https:/www.ietf.org/archive/id/draft-ietf-lsr-flex-algo-bw-con-08.html*RFC8920__;Iw!!NEt6yMaO-gk!HoQCxz15c5OoUVXjpmPpCU0N94Ex0cMuET6hFT8l6FE_kNkB58lpI-LSmXBUJvY4IdViL2mzTjVwvp4nyibk3A$>], > MUST be compared against the Maximum delay advertised in the FAEMD sub-TLV. > <SH2> I think there is a misunderstanding here. You are proposing to use > sub-tlv 13 where as the text in the draft clearly proposes to use sub-tlv 12. > This probably justifies why it is important to specify sub-tlv number > And not just name. > > > 5) Do we want to call out that the reference bandwidth approach requires a > router to compute and maintain a per link per algo bandwidth metric for every > link in that algo topology. It may not be very obvious to some. > <SH> updated as below > “Advertising > the reference bandwidth in the FAD constraints allows the metric > computation to be done on every node for each link. > The metric is computed using reference bandwidth and the advertised link > bandwidth. > Centralized control of this > reference bandwidth simplifies management in the case that the > reference bandwidth changes” > > KT> The above text is not really needed IMHO. My point was more about the > implementation detail - for the flexalgo computation, we need to maintain > this info on a per link per algo topology basis in the link-state data store > used for path computation. I will leave it to the authors if this is needed > or is obviously clear to implementers. > <SH2> I don’t see the need to add implementation specific details. > > > 6) There are a lot of procedures which are common to both OSPF and ISIS and > are repeated in each section instead of a common section. It would be easier > (and avoid errors) if there was some consolidation. > https://www.rfc-editor.org/rfc/rfc9350.html#section-5 > <https://urldefense.com/v3/__https:/www.rfc-editor.org/rfc/rfc9350.html*section-5__;Iw!!NEt6yMaO-gk!DwOojW2YZ48IROz9qMyyh7uKj3rYC-09avEhFQtcPkvxJ5mKF5Cyy6qSVvDJ89s9DmAUVwsT_pgfmumpoQRYAA$> > provides a good reference for such an organization of text. > <SH> There is repetition in some cases but its not much so it seems to me > leaving it as is for clarity may be better. > > KT> This is an editorial comment so I leave it to the authors. My concern is > that great care/diligence is required through the rest of the publication > process to ensure that when anything is changed or updated for one IGP, it is > done appropriately for the other as well - it may be copy/paste case when the > change is IGP agnostic but may need careful consideration when related to the > specific IGP mechanics. > > > 7) Regarding > https://www.ietf.org/archive/id/draft-ietf-lsr-flex-algo-bw-con-08.html#section-6 > > <https://urldefense.com/v3/__https:/www.ietf.org/archive/id/draft-ietf-lsr-flex-algo-bw-con-08.html*section-6__;Iw!!NEt6yMaO-gk!DwOojW2YZ48IROz9qMyyh7uKj3rYC-09avEhFQtcPkvxJ5mKF5Cyy6qSVvDJ89s9DmAUVwsT_pgfmumnzxX7UA$>, > it seems like we want to retain a numbering ordering of rules/sequence for > flex-algo as extension documents are introduced. Am I correct? If so, then > this document should formally "update" RFC9350 since it is changing the "set > of rules/sequence" for FlexAlgo computations. Further such extensions will > also need to keep updating the base spec similarly. I would suggest that a > full set of rules that is a union of what is in RFC9350 and rules added by > this draft are maintained in an Appendix section. Other documents in the > future can similarly maintain the latest set of rules. > <SH> This draft is adding 2 new rules at the end of existing rules. Its not > modifying or changing the order. > I don’t see what value it is going to add by repeating the set of rules in > Appendix. > > KT> What happens when another FlexAlgo document adds more rules? What happens > when some FlexAlgo document wants to insert rules in the middle of existing > ones instead of appending at the end? My point is that if there is a desire > to establish a "live" set of rules in specific orders, then we need to leave > a trail of document "updates" on the base FlexAlgo that one can refer to know > how these "live set of rules" are getting "updated" by this and future > documents. I am thinking of this on lines similar to an update for an FSM. > <SH2> It’s a matter of choice. For ex RFC 8029 > Has so many updates to the Rules but each update only lists the > changes. > I am fine with whatever WG decides to do. > I want to hear if anyone in WG has an opinion on adding Appendix. > > Thanks, > Ketan > > > > 8) Please fix idnits warnings - some are related to obsolete references while > others are related to formatting. There are also some spelling/grammar errors. > <SH> ok > > Thanks, > Ketan > > > On Tue, Feb 20, 2024 at 3:56 AM Acee Lindem <acee.lin...@gmail.com > <mailto:acee.lin...@gmail.com>> wrote: > > This starts the Working Group Last call for > draft-ietf-lsr-flex-algo-bw-con-07. At least some of the flex algorithm > enhancements described in the document have been implemented. > > Please send your support or objection to this before March 5th, 2024. > > Thanks, > Acee > _______________________________________________ > Lsr mailing list > Lsr@ietf.org <mailto:Lsr@ietf.org> > https://www.ietf.org/mailman/listinfo/lsr > <https://urldefense.com/v3/__https:/www.ietf.org/mailman/listinfo/lsr__;!!NEt6yMaO-gk!DwOojW2YZ48IROz9qMyyh7uKj3rYC-09avEhFQtcPkvxJ5mKF5Cyy6qSVvDJ89s9DmAUVwsT_pgfmukG-EHJRw$> > _______________________________________________ > Lsr mailing list > Lsr@ietf.org <mailto:Lsr@ietf.org> > https://www.ietf.org/mailman/listinfo/lsr > > _______________________________________________ > Lsr mailing list > Lsr@ietf.org > https://www.ietf.org/mailman/listinfo/lsr
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