Re: [rmcat] AD review of draft-ietf-rmcat-sbd-09
Anna Brunstrom <anna.brunstrom@kau.se> Tue, 06 February 2018 15:30 UTC
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To: Michael Welzl <michawe@ifi.uio.no>, "Mirja Kuehlewind (IETF)" <ietf@kuehlewind.net>
CC: "rmcat WG (rmcat@ietf.org)" <rmcat@ietf.org>, draft-ietf-rmcat-sbd.all@ietf.org
References: <227D2FC6-A331-4311-A8BF-E783B9F0B8EB@kuehlewind.net> <1b78e928-3fb3-7959-552a-e4c9bbcd7af6@kau.se> <1E245578-0EC9-4496-A683-9FBFBA1FC5C2@kuehlewind.net> <5E43ED74-2BBF-4E1E-8C4B-21D2D718E2F2@ifi.uio.no>
From: Anna Brunstrom <anna.brunstrom@kau.se>
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Date: Tue, 06 Feb 2018 16:30:36 +0100
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Subject: Re: [rmcat] AD review of draft-ietf-rmcat-sbd-09
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Hi, On 2018-02-06 13:34, Michael Welzl wrote: > Hi, > > As an author, first of all, thanks for your feedback! > > I’m answering a point below: > > >> On Feb 6, 2018, at 9:21 AM, Mirja Kuehlewind (IETF) >> <ietf@kuehlewind.net <mailto:ietf@kuehlewind.net>> wrote: >> >> >> >>> Am 06.02.2018 um 02:18 schrieb Anna Brunstrom <anna.brunstrom@kau.se >>> <mailto:anna.brunstrom@kau.se>>: >>> >>> Hi Mirja, all, >>> >>> Comments inline. >>> >>> On 2018-02-02 17:04, Mirja Kuehlewind (IETF) wrote: >>>> Hi authors, hi chairs, >>>> >>>> many thanks for this very well written document as well as a good >>>> write-up from the shepherd! >>>> >>>> Before I start the IETF LC call I have two small questions: >>>> >>>> 1) Normative references: >>>> >>>> I wonder if draft-ietf-rmcat-coupled-cc should be a normative >>>> reference, especially as it is mentioned in the abstract, but also >>>> because it probably helps to at least read section 4 (architecture) >>>> of draft-ietf-rmcat-coupled-cc. >>> >>> My understanding is that only normative statements create normative >>> references, so the fact that it is mentioned in the abstract or >>> useful to read does not make it normative? As I am not so >>> experienced with the process I looked for guidelines on this before >>> reviewing the draft and this is at least what >>> draft-peterson-informational-normativity-01 suggests. >> >> Normative references and normative language are two different things. >> A reference should be normative if it is (or part of it) a required >> read to understand the content of the document. E.g. if you write an >> TCP extension the RFC defining the TCP base protocol must be a >> normative reference. So my question is here, do you think that couple >> congestion is a required read to understand this document (I’m asking >> this because there is this architecture section in >> draft-ietf-rmcat-coupled-cc). I did not mean to suggest that normative references and normative language were the same. I was referring to these guidelines from the draft mentioned above: /For the benefit of specification authors, the following is a list of conditions in which a reference to a document need not be normative:// // 1. if the source document is itself Informational (not a standards-track document, BCP or an Experimental document).// // 2. if the referencing statement is not a normative statement; i.e., does not prescribes some degree of normative compliance with the target document.// // 3. if the target document, and in particular any subset scope designated by the referencing statement (a section, or what have you), contains no normative statements./ Either way, I do not think that coupled congestion control is a required read to understand the SBD document. For the next update the authors may perhaps still consider removing the reference from the abstract, as it may in general look a bit odd. > I’m not Anna, but at least I think that, despite there being an > architecture section in draft-ietf-rmcat-coupled-cc, it is not a > required read to understand draft-ietf-rmcat-sbd-09. It really > shouldn’t be: SBD is just a mechanism that provides information about > flows traversing common bottlenecks. Coupled-cc is a mechanism that > can use it (it doesn’t have to, but if you combine them, you can, > e.g., couple flows from one sender towards multiple receivers). > > Here is an example of how the SBD algorithm can be used independent > of draft-ietf-rmcat-coupled-cc: > > Simone Ferlin, Ozgu Alay, David Hayes, Thomas Dreibholz, Michael > Welzl: "Revisiting Congestion Control for Multipath TCP with Shared > Bottleneck Detection", IEEE Infocom 2016, San Francisco, USA, 10-15 > April 2016. > http://heim.ifi.uio.no/michawe/research/publications/infocom2016.pdf > > >>>> Further this sentence seems to make avtcore-cc-feedback-message >>>> should also be a normative reference: >>>> "Timing information described by >>>> [I-D.ietf-avtcore-cc-feedback-message] should be sufficient for the >>>> sender to calculate relative OWD.“ >>>> I don’t think we want to wait for avtcore-cc-feedback-message for >>>> publication, therefor I would recommend to say something about the >>>> resolution used in avtcore-cc-feedback-message, e.g. >>>> „Frequent timing information in millisecond resolution as described by >>>> [I-D.ietf-avtcore-cc-feedback-message] should be sufficient for the >>>> sender to calculate relative OWD.“ >>> >>> From the same reasoning as above, I am not sure that this is a >>> normative reference either? But I agree that your proposal to >>> mention the resolution is much better! Actually, reading the text >>> now we should probably also avoid the lower case should just to not >>> confuse it with SHOULD, Perhaps "will be" or "is believed to be" or >>> something similar instead of "should be“. >> >> There is no need to avoid lower case should. Actually there is the >> update of RFC2119 which clarifies this. You should probably also use >> the new boilerplate of RFC8174. Forgot to mention that! Ok, good I had missed this. Authors, please add updating the boilerplate to the list for the next draft update. >> >>> >>>> 2) I can't remember if this was discussed in the group but actually >>>> I believe it was not: this document could also be an informational >>>> document, as it is just one example algorithm but there are no >>>> dependencies on this scheme otherwise. I also don’t think is makes >>>> too much sense to think about this proposed algorithm as an >>>> experiment; if you want to change the algorithm or use a different >>>> one just do it; this is just a documentation of one proposal. I >>>> also assume that there is actually not much interest in the group >>>> to publish an updated version of this algorithm as proposed >>>> standard, as such why not informational from the beginning…? >>>> >>>> If the authors and the group are uncertain about this point, I’m >>>> okay to start IETF LC as exp and see if we can get further feedback >>>> there or from the IESG; „downgrading“ to information can easily be >>>> done with any additional actions at any time. >>> >>> This is not something that has been discussed as far as I know, but >>> I am not sure what happened in the beginning of the process. Unless >>> the authors prefer to have it informational I would not like to >>> change the status at this point as this is not something that has >>> been discussed in the group. I also do not think it is fully correct >>> to say that SBD does not interact with other mechanisms in the >>> network as it can affect congestion control and the performance of >>> other flows. So the need to verify a sane and useful behavior still >>> seems to be applicable here. >> >> I didn’t say it didn’t interact but it does not need to be >> standardized for interoperability. >> >> If we would decide to change the status, in agreement with the >> authors of course, I think it would be okay to simply announce it on >> the mailing list. I would not expect to see a lot of discuss there. I >> will wait for feedback from the authors. However, I don’t have a >> strong opinion here. > > We believe that Experimental status is more fitting; we looked at the > checklist here, from which this seems a pretty clear decision to us: > https://www.ietf.org/standards/process/informational-vs-experimental Ok, thanks for the feedback Michael. Then we stay with experimental. Best Regards, Anna > > Cheers, > Michael >
- [rmcat] AD review of draft-ietf-rmcat-sbd-09 Mirja Kuehlewind (IETF)
- Re: [rmcat] AD review of draft-ietf-rmcat-sbd-09 Anna Brunstrom
- Re: [rmcat] AD review of draft-ietf-rmcat-sbd-09 Mirja Kuehlewind (IETF)
- Re: [rmcat] AD review of draft-ietf-rmcat-sbd-09 Michael Welzl
- Re: [rmcat] AD review of draft-ietf-rmcat-sbd-09 Anna Brunstrom
- Re: [rmcat] AD review of draft-ietf-rmcat-sbd-09 Michael Welzl
- Re: [rmcat] AD review of draft-ietf-rmcat-sbd-09 Mirja Kühlewind
- Re: [rmcat] AD review of draft-ietf-rmcat-sbd-09 Michael Welzl
- Re: [rmcat] AD review of draft-ietf-rmcat-sbd-09 Mirja Kuehlewind (IETF)
- Re: [rmcat] AD review of draft-ietf-rmcat-sbd-09 Mirja Kuehlewind (IETF)