[nmrg] draft-irtf-nmrg-snmp-measure-05.txt now moving to IRSG for approval
"Bert Wijnen - IETF" <bertietf@bwijnen.net> Sun, 01 June 2008 14:47 UTC
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From: Bert Wijnen - IETF <bertietf@bwijnen.net>
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Date: Sun, 01 Jun 2008 16:47:50 +0200
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Cc: Internet Research Steering Group <irsg@isi.edu>, "Karen R. Sollins" <sollins@csail.mit.edu>, j.schoenwaelder@jacobs-university.de
Subject: [nmrg] draft-irtf-nmrg-snmp-measure-05.txt now moving to IRSG for approval
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Since I have seen no further reaction on the NMRG list I assume we are all happy with this document (revision 5), I am going to ask the IRSG to approve it for publication. Bert Wijnen document shepherd > -----Oorspronkelijk bericht----- > Van: nmrg-bounces@ibr.cs.tu-bs.de > [mailto:nmrg-bounces@ibr.cs.tu-bs.de]Namens Bert Wijnen - IETF > Verzonden: maandag 19 mei 2008 23:49 > Aan: Karen R. Sollins; j.schoenwaelder@jacobs-university.de > CC: Internet Research Steering Group; nmrg@ibr.cs.tu-bs.de > Onderwerp: [nmrg] RE: [IRSG] review of > draft-irtf-nmrg-snmp-measure-04.txt > > > Karen, > Juergen has posted revision 5 with the fixes/updates as you > and he discussed. If you could quickly check that revision 5 is now OK > with you and let us all know if so, that would be appreciated. > > The document is here: > http://www.ietf.org/internet-drafts/draft-irtf-nmrg-snmp-measure-05.txt > > NMRG members, pls check and speak up if you see any issues in the > changes that were made for revision 5 as a result of IRSG review. > > Bert Wijnen > document shepherd > > > -----Oorspronkelijk bericht----- > > Van: Karen R. Sollins [mailto:sollins@csail.mit.edu] > > Verzonden: maandag 19 mei 2008 19:25 > > Aan: j.schoenwaelder@jacobs-university.de; Karen R. Sollins > > CC: nmrg@ibr.cs.tu-bs.de; Bert Wijnen - IETF; Internet Research Steering > > Group > > Onderwerp: Re: [IRSG] review of draft-irtf-nmrg-snmp-measure-04.txt > > > > > > HI Juergen, > > > > It is all fine with me. I think all you need now is concurrence from > > the research group. > > > > Cheers, > > Karen > > > > At 11:46 AM +0200 5/19/08, Juergen Schoenwaelder wrote: > > >On Sun, May 18, 2008 at 09:05:15PM -0700, Karen R. Sollins wrote: > > > > > >> Thanks for your thoughtful responses. I also did not think > > that what I was > > >> suggesting was a lot of work. At a high level, think about > > a reader who > > >> is not part of your group, whom you are trying to convince > > that what you > > >> are doing is valuable or whom you would like to convince to > > do such a data > > >> collection exercise. I have interspersed my comments into > > your responses > > >> below. > > > > > >I will repond to those things that are still "open" with suggestions > > >on how to "close" them. > > > > > >KS> The second high level concern I have is that there is talk about > > >KS> specific kinds of information to be collected and an > interest in not > > >KS> only the nature but longer term inferences with perhaps > implications > > >KS> for future redesign efforts in the SNMP context. I have > > two levels > > >KS> of concern here. The most important one is that since network > > >KS> management and in particular SNMP is NOT the primary > > objective of the > > >KS> net (the primary objective being the transport of real > payload), it > > >KS> seems to me that the truly critical question with respect > to network > > >KS> management traffic is the impact that it has or does not > > have on that > > >KS> real job. To me this implies that the measurements MUST > > also include > > >KS> contextual information. As an example, it is probably more > > important > > >KS> to understand whether or not the network management traffic is > > >KS> causing significant congestion for the payload traffic than the > > >KS> particular mix or frequency pattern within the network management > > >KS> traffic. Without out the complementary contextual > information, the > > >KS> whole measurement exercise seems to me to be of somewhat narrow > > >KS> value. > > > > > >JS> The measurement may be of narrow value from your point of view but > > >JS> please keep in mind that this document is coming from the Network > > >JS> Management Research Group and not from a general Network > Measurement > > >JS> Research Group. Our goal is to understand how network management > > >JS> protocols are being used because that has impact on their > design and > > >JS> implementation strategies. Further note that in many networks, the > > >JS> management traffic is logically and sometimes even physically > > >JS> separated from the normal traffic and perhaps this is the > reason why > > >JS> we did not even think about the question whether management traffic > > >JS> has an impact on normal traffic. > > > > > >KS> If you want to leave it as is, then I think it would be > > valuable to say as > > >KS> much. Be specific about what you are not doing, because > > much of the rest > > >KS> of the world looks at network traffic from a broader perspective. > > > > > >I think the abstract and the introduction are pretty clearly spelling > > >out the scope of the measurement effort. So I am not sure changes are > > >needed, but see below. > > > > > >KS> 1. Section 1: It seems to me that there are TWO key questions with > > >KS> respect to SNMP. The first is how it is being used, which in turn > > >KS> leads to the points made in this section, but the second is the > > >KS> impact of that traffic. I think that ought to appear in the > > >KS> Introduction as well. > > > > > >JS> See my comments above. So far, the NMRG did not consider the > > impact of > > >JS> SNMP on other traffic a target of this activity. I don't > want to add > > >JS> such text unless I see support from the NMRG and concrete proposals > > >JS> what should be added. > > > > > >KS> Again, as above, if you want to leave the scope as it is, > > then you should > > >KS> probably be up front about that, clearly leaving that work > > to another time > > >KS> and place. > > > > > >I propose to add the following paragraph just before the last > > >paragraph in section 1: > > > > > > The measurement approach described in this document is by design > > > limited to the study of SNMP traffic. Studies of other management > > > protocols or the impact of management protocols such as SNMP on > > > other traffic sharing the same network resources is left to future > > > efforts. > > > > This is what I was looking for. > > > > >KS> 2. Section 2.1. The second paragraph begins with, "It is > > recommended > > >KS> to capture at least a full week of data." This is never > > justified or > > >KS> explained. Is one week really enough? For what? Why wouldn't > > >KS> several weeks be critical, because one week might be > anomalous? Why > > >KS> isn't a year critical, since we know that there are annual or > > >KS> seasonal differences in traffic behaviors? Typically, I find that > > >KS> one-week data sets often leave me with lots of unanswered > questions, > > >KS> so justify this. > > > > > >JS> The text actually says: > > >JS> > > >JS> It is recommended to capture at least a full week of > > data. Operators > > >JS> are encouraged to capture traces over even longer > periods of time. > > >JS> > > >JS> The text tries to establish a lower bound of one week an encourages > > >JS> longer capture periods. I would love to get continuous traces but > > >JS> reality is such that this is not feasible. Our idea is > > simply to catch > > >JS> at least the weekly behaviour. Yes, there is of course also > > monthly or > > >JS> yearly behaviour but I believe it is not useful to set the > > bar so high > > >JS> that nobody gives us appropriate traces. I personally > > believe the text > > >JS> is fine as is. > > > > > >KS> So, what I was really getting at was the question of why one week > > >KS> was the minimum necessary. So, something like that it is the > > >KS> minimum over which one can see the diurnal patterns in the weekly > > >KS> pattern and it is understood that both for computational and > > >KS> storage reasons the operators may not want to collect more. > > > > > >I have changed the text to the following: > > > > > > It is recommended to capture at least a full week of data > to capture > > > diurnal patterns and one cycle of weekly behavior. Operators are > > > strongly encouraged to capture traces over even longer periods of > > > time. > > > > OK by me. > > > > >KS> 4. Section 3.3, end of first paragraph: The sentence reads, "Some > > >KS> SNMP implementations approximate networking delays by measuring > > >KS> request-response times and it would be useful to > understand to what > > >KS> extent this is a viable approach." I agree, but traces > > will not tell > > >KS> you anything about whether behaviors observed in packet traces are > > >KS> for this reason or some other reason. I do not believe > you can get > > >KS> at this question with the data you are collecting. > > > > > >JS> I think it is possible to analyze retransmission > behaviour. Depending > > >JS> on the SNMP version used (and the other versions also depending on > > >JS> implementation choices), you can get information whether a > > response is > > >JS> just coming late for the original request or it is actually > > a response > > >JS> to a retranmitted request. We are not talking TCP here; we > > are talking > > >JS> about application layer retransmissions and SNMP has its own > > msgID and > > >JS> requestID fields. > > > > > >KS> The point I was trying to make here is that it is very > > difficult to intuit > > >KS> the reasons behind behaviors seen in the traffic, unless someone or > > >KS> something tells you. So, you can see what the ends do, > but not why. > > > > > >I agree, but this is a rather general observation and not necessarily > > >specific to 3.3 and it is not clear to me what I should do about it. > > >There is already a general remark in the last paragraph of section 2.5 > > >that one has to be careful with drawing conclusions that go beyond > > >what you can really get out of traces. > > > > OK - I'll drop it. > > > > > > > >KS> 5. Section 3.4: Please explain why it is "interesting" > > (your word) to > > >KS> identify whether concurrency or sequentiality is occurring? What > > >KS> will you "learn" if both are observed? And, if one is > > occurring more > > >KS> frequently or under specific identifiable conditions, what further > > >KS> does that tell you? Just knowing that one or the other occurs is > > >KS> only the tip of the iceberg, and without acknowledging > the fact that > > >KS> these are important and unanswered questions, just learning first > > >KS> ordered details suggests you are setting the bar too low. > > > > > >JS> The introduction of section 3 says: > > >JS> > > >JS> The questions raised in the following subsections are > meant to be > > >JS> illustrative and no attempt has been made to provide a complete > > >JS> list. > > >JS> > > >JS> I believe it is a good idea to first figure out whether there is an > > >JS> iceberg or not (keeping your analogy) and if there is one to ask > > >JS> questions how big the iceberg might be. For SNMP agent > > implementations > > >JS> that tend to do quite some caching, it is useful to know how well > > >JS> caching strategies are working in real-world networks. The > > concurrency > > >JS> level an agent experiences has clear impact on that. > Furthermore, it > > >JS> will be useful to know how bursty the traffic tends to be > or how well > > >JS> managers spread the traffic over polling intervals and > this is again > > >JS> related to the concurrency we can extract from traces. > > >JS> > > >JS> I am not really sure what I should change, perhaps the word > > >JS> "interesting" is the source of the trouble and I should > replace this > > >JS> with "valuable"? > > > > > >KS> What I was trying to ask was that you tell the reader a bit about > > >KS> what makes it interesting. It certainly doesn't have to be > > >KS> complete, but just a> hint. I don't think you should change the > > >KS> word "interesting", because if it isn't interesting, you probably > > >KS> shouldn't be doing it. > > > > > >I added the following sentence to section 3.4: > > > > > > The concurrency level and the amount of redundant requests has > > > implications on caching strategies employed by SNMP agents. > > > > Fine. > > > > >KS> 6. Section 3.5: Please explain what you would do with the > > >KS> information about which approach to table retrieval is > used. Again, > > >KS> what if the results tell you that both are used? And, if not, of > > >KS> what use is it to know which approach is prevalent? Mighten it be > > >KS> useful to know the conditions under which one or the other is used > > >KS> more commonly? > > > > > >JS> This again has direct impact on agent implementation techniques and > > >JS> caching strategies. > > > > > >KS> And again, just explain a little. > > > > > >I changed the last sentence of section 3.5 to read as follows: > > > > > > [...] It will be useful to know which of > > > these approaches are used on production networks since this has a > > > direct implication on agent implementation techniques and caching > > > strategies. > > > > Fine. > > > > >/js > > > > > >-- > > >Juergen Schoenwaelder Jacobs University Bremen gGmbH > > >Phone: +49 421 200 3587 Campus Ring 1, 28759 Bremen, Germany > > >Fax: +49 421 200 3103 <http://www.jacobs-university.de/> > > > > > > -- > > > > Karen R. Sollins, Ph. D. > > Principal Research Scientist > > M.I.T. CSAIL > > The Stata Center > > 32 Vassar St., 32-G818 > > Cambridge, MA 02139 > > V: 617/253-6006 > > F: 617/253-2673 > > E: sollins@csail.mit.edu > > > > -- > !! This message is brought to you via the `nmrg' mailing list. > !! Please do not reply to this message to unsubscribe. To > unsubscribe or adjust > !! your settings, send a mail message to <nmrg-request@ibr.cs.tu-bs.de> > !! or look at https://mail.ibr.cs.tu-bs.de/mailman/listinfo/nmrg. >
- [nmrg] RE: [IRSG] review of draft-irtf-nmrg-snmp-… Bert Wijnen - IETF
- [nmrg] Re: [IRSG] review of draft-irtf-nmrg-snmp-… Juergen Schoenwaelder
- RE: [nmrg] Re: [IRSG] review of draft-irtf-nmrg-s… David B Harrington
- Re: [nmrg] Re: [IRSG] review of draft-irtf-nmrg-s… Juergen Schoenwaelder
- [nmrg] Re: [IRSG] review of draft-irtf-nmrg-snmp-… Karen R. Sollins
- RE: [nmrg] Re: [IRSG] review of draft-irtf-nmrg-s… David B Harrington
- [nmrg] Re: [IRSG] review of draft-irtf-nmrg-snmp-… Juergen Schoenwaelder
- [nmrg] RE: [IRSG] review of draft-irtf-nmrg-snmp-… Bert Wijnen - IETF
- [nmrg] Re: [IRSG] review of draft-irtf-nmrg-snmp-… Karen R. Sollins
- [nmrg] Re: [IRSG] review of draft-irtf-nmrg-snmp-… Juergen Schoenwaelder
- [nmrg] review of draft-irtf-nmrg-snmp-measure-04.… Karen R. Sollins
- RE: [nmrg] draft-irtf-nmrg-snmp-measure-05.txt no… Medhi, Deep
- [nmrg] draft-irtf-nmrg-snmp-measure-05.txt now mo… Bert Wijnen - IETF