RE: [ippm] draft-shalunov-ippm-reporting-00.txt

Dear Stanislav,

I read your draft and I think it is going in the 
right direction. Some suggestions for the next 
version from my point of view are:

* Motivation: should state some application areas, i.e.
  "why would a human user want to get those values" - e.g.
  'to check that IP telephony would be feasable with available QoS'

* please don't be offended, but I disagree on the traffic 
  statistics you plan to apply to the traffic metrics.
  To me they seem to be quite unusual. see below:

* delay: I would suggest to use mean or a high percentile as
  I have never seen median delay to be used to report QoS

* loss: just a typo = per cent -> percent

* jitter: as far as I know the two common defintions are 
  (high) percentile minus min delay across some interval
  (ITU approach) or min/max of IP delay variation, taken from
  the series of differences of consecutuve OWD values (IETF approach)

* duplication: just lacks definition of a default timeout value

* additionally I think two things will need to be added to the draft:
  a) mentioning about the size of the interval about which all
     those metrics are obtained and the fact whether this will be 
     a sliding window or fixed time slots, e.g. new values each 10sec
  b) I'd personally like to see some "packet filter" added to the
     reporting record. Data might relate only to a fraction of all
     traffic, e.g. only to UDP or only to traffic from videos.fun.org

* additionally "availability" could be one metric
  (probably with param = (list of) server(s) or network)

* a small final note (not specific to the draft): when applying the 
  ITU definition for jitter, then high percentile of delay and jitter
  are quite correlated, and just differ by the interval's min-delay.
  I cannot say if/how they correlate when the IETF definition (IPDV) is
used.

* one question from my side: how would you define/report the measurement
parameters?
  (i.e. the src/dst/network/path to which the reported delay/jitter etc.
applies)

With best regards,
Carsten.

> -----Original Message-----
> From: stanislav shalunov [mailto:shalunov@internet2.edu] 
> Sent: Monday, April 10, 2006 4:16 AM
> To: ippm@ietf.org
> Subject: [ippm] draft-shalunov-ippm-reporting-00.txt
> 
> I did not see this announcement on the IPPM list.
> 
> Internet-Drafts@ietf.org writes:
> 
> > Network measurement has many purposes.  Often, the ultimate purpose
> > is to report a concise set of metrics describing a 
> network's state to
> > an end user.  The aim of this document is to define a small set of
> > metrics that are robust, easy to understand, orthogonal, relevant,
> > and easy to compute.
> > 
> > A URL for this Internet-Draft is:
> > 
> http://www.ietf.org/internet-drafts/draft-shalunov-ippm-report
ing-00.txt
> 
> -- 
> Stanislav Shalunov		http://www.internet2.edu/~shalunov/
> 
> Al your Qaeda are belong to US.
> 
> _______________________________________________
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> ippm@ietf.org 
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> 
> 

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