RE: [nmrg] draft-irtf-nmrg-snmp-measure-05.txt now moving to IRSG forapproval
"Medhi, Deep" <DMedhi@umkc.edu> Sun, 01 June 2008 16:51 UTC
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Subject: RE: [nmrg] draft-irtf-nmrg-snmp-measure-05.txt now moving to IRSG forapproval
Date: Sun, 01 Jun 2008 11:50:48 -0500
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From: "Medhi, Deep" <DMedhi@umkc.edu>
To: Bert Wijnen - IETF <bertietf@bwijnen.net>, nmrg@ibr.cs.tu-bs.de
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Cc: Internet Research Steering Group <irsg@isi.edu>, "Karen R. Sollins" <sollins@csail.mit.edu>, j.schoenwaelder@jacobs-university.de
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Just to confirm; this version is fine with me. -- Deep Deep Medhi, Ph.D. Professor, Computer Science & Electrical Engineering Department, University of Missouri-Kansas City, USA, Tel: +1-816-235-2006, http://www.csee.umkc.edu/~dmedhi Chair, Internet Technical Committee, http://www.comsoc.org/~itc > -----Original Message----- > From: nmrg-bounces@ibr.cs.tu-bs.de [mailto:nmrg-bounces@ibr.cs.tu- > bs.de] On Behalf Of Bert Wijnen - IETF > Sent: Sunday, June 01, 2008 9:48 AM > To: nmrg@ibr.cs.tu-bs.de > Cc: Internet Research Steering Group; Karen R. Sollins; > j.schoenwaelder@jacobs-university.de > Subject: [nmrg] draft-irtf-nmrg-snmp-measure-05.txt now moving to IRSG > forapproval > > 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. > > > > -- > !! 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