Re: [SAM] [irsg] IRSG review for draft-irtf-samrg-sam-baseline-protocol-02
Michael Welzl <michawe@ifi.uio.no> Wed, 01 May 2013 09:38 UTC
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From: Michael Welzl <michawe@ifi.uio.no>
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To: "Thomas C. Schmidt" <schmidt@informatik.haw-hamburg.de>, Internet Research Steering Group <irsg@irtf.org>, "sam@irtf.org" <sam@irtf.org>
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Subject: Re: [SAM] [irsg] IRSG review for draft-irtf-samrg-sam-baseline-protocol-02
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Hi, Yes. One (non-blocking) question: why is this intended as Informational, and not Experimental? The latter would seem more appropriate to me. Cheers, Michael On Apr 28, 2013, at 10:00 AM, Thomas C. Schmidt <schmidt@informatik.haw-hamburg.de> wrote: > Hi Michael, > > this means a "ready to publish" vote? > > Viele Grüße > > Thomas > > On 28.04.2013 07:23, Michael Welzl wrote: >> Hi, >> >> I just noticed that somehow, irsg and samrg were dropped from the list >> of recipients of this response, sorry >> >> Begin forwarded message: >> >>> *From: *Michael Welzl <michawe@ifi.uio.no <mailto:michawe@ifi.uio.no>> >>> *Subject: **Re: [irsg] IRSG review for >>> draft-irtf-samrg-sam-baseline-protocol-02* >>> *Date: *April 24, 2013 4:06:17 PM GMT+02:00 >>> *To: *Dr Mario Kolberg <mko@cs.stir.ac.uk <mailto:mko@cs.stir.ac.uk>> >>> *Cc: *sam <sam@irtf.org <mailto:sam@irtf.org>>, John Buford >>> <buford@samrg.org <mailto:buford@samrg.org>> >>> >>> Hi, >>> >>> In line: >>> >>> >>> On 22. apr. 2013, at 12:36, Dr Mario Kolberg wrote: >>> >>>> Hi Michael and All, >>>> >>>> please find below our response to the IRSG review by Michael Welzl. >>>> >>>> Best wishes, >>>> Mario & John >>>>> >>>>> General higher-level comments: >>>>> >>>>> 1) I found parts of the document very hard to read, sometimes >>>>> wondered if this is really necessary. >>>>> >>>> The document is intended for an audience which does have a technical >>>> background in the area of application layer multicasting and peer to >>>> peer overlay protocols. We would expect readers unfamiliar with the >>>> area to first go to more basic material. Perhaps many comments in the >>>> review stem from the fact that the reviewer doesn’t have this >>>> familiarity. To help readers to get a better understanding we have >>>> added references to introductory and background material as a >>>> starting point: >>>> >>>> J. Buford, H. Yu, E. K. Lua P2P Networking and Applications. Morgan >>>> Kaufman 2009 (Ch 9 Peercasting and Overlay Multicasting). >>>> M. Kolberg. Employing Multicast in P2P Networks, in: Handbook of >>>> Peer-to-Peer Networking. (Ed. X. Shen, H. Yu, J. Buford, M. Akon). >>>> J. Buford and H. Yu. Peer-to-Peer Overlay Multicast, in: Encyclopedia >>>> of Wireless and Mobile Communications. 2008. >>>> >>> Good! >>> I would like to mention that, while I know very little about >>> application layer multicast, I do have some (outdated) P2P knowledge. >>> It's not really my field, but I have done a little bit of work on it >>> and also taught a lecture about it a few years ago (which even >>> contained a brief overview of Scribe, IIRC). So that made me think, >>> someone like me should at least be able to make some sense of the >>> document - within certain limits of course, as I know nothing about >>> RELOAD, for example. >>> >>> >>>>> 2) In particular, P2PCast appears to be a rather complex algorithm >>>>> which is "sort of" described here... I doubt that the description in >>>>> the document will help most readers to really fully understand >>>>> P2PCast, and I wonder, is it necessary for this doc to try to >>>>> really explain the algorithm (when, in doing so, it can really only >>>>> go half-way anyway)? e.g., wouldn't it suffice to just keep the >>>>> "Overview" (section 9.1) but then point to [P2PCAST] for further >>>>> details, and just list the necessary facts? e.g., the JOIN procedure >>>>> - do we have to know all these details here, isn't it enough to e.g. >>>>> list the reorganisation messages by name and say that they're used >>>>> in accordance with [P2PCAST]? >>>> The ID is written for a technical audience which is presumed to be >>>> knowledgeable about RELOAD and P2P overlays and has somefamiliarity >>>> with multicasting at the application layer. We provide summaries of >>>> P2PCAST and SCRIBE since these two algorithms are well known in the >>>> ALM research community, and are each representative of an important >>>> class of ALM algorithms. If the reader needs more background, then >>>> they can go to thereference papers and find it there. >>>> >>>> In our opinion, the inclusion of the essential features about each >>>> algorithm is useful and should be in the ID. The level of >>>> detaildescribes “Scribe-like” and “P2PCast-like” algorithms, and not >>>> only Scribe and P2PCAST. Since the protocol we define is intended to >>>> support a large variety of such algorithms. >>>> >>>> This is done in other in other IDs and RFCs. For example, please >>>> take a look at section 10 of the RELOAD ID which gives detailed >>>> information about the Chord algorithm, but yet omits Chord details >>>> which one would find in the original papers from MIT. If your >>>> comments were followed, this Chord material should be removed from >>>> RELOAD spec. Likewise see this id produced by the PPSP WG >>>> draft-ietf-ppsp-survey-04. There are lots of other examples where >>>> important previously existing algorithms are summarized in an ID. >>> >>> Well. I'm not sure if the cases you compare here really are comparable >>> - the Chord text in the RELOAD ID is much longer, for a (it seems to >>> me) much simpler algorithm, and a survey is really a different case, I >>> think - its overall intention is different from a document like this >>> one. But I see your point about trying to convey the essential >>> features right here, and if you feel the text explains the essential >>> bits and is helpful, I'll trust you on this one, given my lack of >>> expertise in application-layer multicast. >>> >>> >>>>> 3) Another source of confusion: the Scribe algorithm description has >>>>> some pseudocode that I wasn't able to parse (maybe it refers to >>>>> RELOAD things?) Not all functions there seem to clearly relate to >>>>> messages that were described earlier. Even more confusing, the >>>>> P2PCast algorithm description doesn't have these pseudocode >>>>> snippets, so the whole thing appears inconsistent. Should it be >>>>> everywhere? Should it be removed? If it stays, some explanations are >>>>> needed. It can't be up to the reader to guess what e.g. >>>>> "invokeMessageHandler" does, right?? (section 8.7). In this >>>>> particular section, I would also expect the text and/or pseudocode >>>>> to somehow draw a relationship to "push" (listed in fig. 3), but >>>>> that's not there... so what is this? >>>> >>>> We agree that this pseudocode is more general and applies to both >>>> algorithms. To avoid duplication, we have moved it from Section 8 to >>>> the relevant subsections in Section 7. >>> >>> Fine. >>> >>>>> 4) Structure: even if the two algorithms are only a part of the >>>>> whole thing you define, the text going with them feels a bit like >>>>> "we've set the stage, now we apply it - the messages you heard about >>>>> before are used like this & that with this & that algorithm". That's >>>>> fine! But it also gives the reader the feeling of that being "part >>>>> 2", i.e. I think it should be at the end, if that makes sense. >>>>> >>>> Yes the algorithms are an application of the material in earlier >>>> sections, but we don't agree that moving it to the end will help the >>>> understanding of the draft. >>> >>> Fine. >>> >>>>> 5) I also think that it would be better to move the examples >>>>> (section 12) to where you introduce the messages, the flow of which >>>>> they illustrate. First I have to imagine what an "INVITE" message >>>>> flow could look like, then I get complicated explanations of how >>>>> INVITE is applied in an algorithm that I can't fully understand from >>>>> this text anyway, and THEN I get a nice example illustrating an >>>>> INVITE message flow... that's not very helpful for the reader I >>>>> think. e.g., when I read 7.2.3, I wondered why the "peer_id" of the >>>>> source peer is even needed in the struct. By looking at the example, >>>>> this would have become clear to me. >>>>> >>>> The document is not meant to be a tutorial, hence the examples are >>>> not first. The examples follow the definition of the messages sothat >>>> the message use is illustrated. If we moved the examples first, then >>>> some other reviewer could then say … why are the examplesshown before >>>> the protocol messages are defined? It is not the purpose of the ID to >>>> bootstrap the reader into basic knowledge of ALM and Peer to Peer >>>> messaging. >>>> >>> Fine. >>> >>>>> 6) Speaking of the examples, what's the point of showing more peers >>>>> than you actually use in the example? Okay, I can understand that >>>>> perhaps you wanted to have the same number for all of them, but then >>>>> you could still remove P3 because it seems that you never use P3 for >>>>> anything in any of the examples. >>>> >>>> We added these peers is to illustrate that 1) not all the peers in >>>> the overlay have to be part of each ALM connection, and 2) the >>>> overlay could have an arbitrary number of peers. >>> >>> Well, even a total P2P nut like myself understands that >>> without even seeing P3, but whatever :-) >>> >>>>> 7) Nits: >>>>> >>>>> IANA Considerations: are you sure that there is nothing? e.g., how >>>>> would a new algorithm code be assigned? (section 11.4) >>>>> - btw, why is the section called "Algorithm Codes" but then the text >>>>> talks about "Algorithm Types" ? >>>>> >>>> There are no IANA considerations since this is to be an informational >>>> RFC. >>> >>> Ah, ok, sure - >>> >>>>> 8) Some references (CASTRO2003, P2PCAST) need a space (I mean, " ") >>>>> after their first appearance. >>>>> cut..... >>>>> >>>> All these edits have been done and version 03 has been submitted. >>> >>> Fine, thanks! >>> >>> Cheers, >>> Michael >>> >> >> >> >> _______________________________________________ >> SAM mailing list >> SAM@irtf.org >> http://www.irtf.org/mailman/listinfo/sam >> > > -- > > Prof. Dr. Thomas C. Schmidt > ° Hamburg University of Applied Sciences Berliner Tor 7 ° > ° Dept. Informatik, Internet Technologies Group 20099 Hamburg, Germany ° > ° http://www.haw-hamburg.de/inet Fon: +49-40-42875-8452 ° > ° http://www.informatik.haw-hamburg.de/~schmidt Fax: +49-40-42875-8409 °
- [SAM] IRSG review for draft-irtf-samrg-sam-baseli… Thomas C. Schmidt
- Re: [SAM] [irsg] IRSG review for draft-irtf-samrg… Michael Welzl
- Re: [SAM] [irsg] IRSG review for draft-irtf-samrg… Thomas C. Schmidt
- Re: [SAM] [irsg] IRSG review for draft-irtf-samrg… Dr Mario Kolberg
- Re: [SAM] [irsg] IRSG review for draft-irtf-samrg… Michael Welzl
- Re: [SAM] [irsg] IRSG review for draft-irtf-samrg… Dr Mario Kolberg
- Re: [SAM] [irsg] IRSG review for draft-irtf-samrg… Michael Welzl
- [SAM] Fwd: [irsg] IRSG review for draft-irtf-samr… Michael Welzl
- Re: [SAM] [irsg] IRSG review for draft-irtf-samrg… Michael Welzl
- Re: [SAM] [irsg] IRSG review for draft-irtf-samrg… Buford, John F (John)
- Re: [SAM] [irsg] IRSG review for draft-irtf-samrg… Michael Welzl
- Re: [SAM] [irsg] IRSG review for draft-irtf-samrg… Eggert, Lars
- Re: [SAM] [irsg] IRSG review for draft-irtf-samrg… John Buford
- Re: [SAM] [irsg] IRSG review for draft-irtf-samrg… Eggert, Lars