Any update? Thanks, Acee
> On Apr 26, 2024, at 11:53 AM, Acee Lindem <acee.lin...@gmail.com> wrote: > > 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> wrote: >> >> Hi Ketan, >> Thanks for reply. >> Pls see inline.. >> >> Juniper Business Use Only >> From: Ketan Talaulikar <ketant.i...@gmail.com> >> Sent: Monday, April 8, 2024 2:25 PM >> To: Shraddha Hegde <shrad...@juniper.net> >> Cc: Acee Lindem <acee.lin...@gmail.com>; lsr <lsr@ietf.org>; >> 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> 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> >> Sent: Thursday, March 21, 2024 10:07 PM >> To: Acee Lindem <acee.lin...@gmail.com> >> Cc: lsr <lsr@ietf.org>; 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]. 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 >> 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 >> <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], 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], 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 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, >> 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> 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 >> https://www.ietf.org/mailman/listinfo/lsr >> _______________________________________________ >> Lsr mailing list >> Lsr@ietf.org >> https://www.ietf.org/mailman/listinfo/lsr > > _______________________________________________ > Lsr mailing list > Lsr@ietf.org > https://www.ietf.org/mailman/listinfo/lsr _______________________________________________ Lsr mailing list -- lsr@ietf.org To unsubscribe send an email to lsr-le...@ietf.org
