Dear Sabine, Qin,
On Thu, Oct 17, 2013 at 2:17 PM, RANDRIAMASY, SABINE (SABINE) < [email protected]> wrote: > Hello,**** > > ** ** > > This is definitely a good idea and it will be interesting to merge the > metric definitions of the current drafts. > Thanks a lot for the work on systematically defining a set of metrics. Please see below. I agree that it is a good idea to merge the definitions. > I started the exercise, using the RFC 6390 definition template > This is a good starting point indeed. We should also define "routingcost" in this metrics document. > and found that there are other definition attributes that highlight the > attractiveness of the ALTO Service that may be used at several layers of > the network, with several levels of control and by several parties. > This multi-level/layer concept is quite interesting. Can you please elaborate a bit? > > > ** > > There has been a number of metrics proposed besides ‘routingcost’ and > ‘hopcount’. One aspect that should be documented is the usage of such > metrics in different environments. For instance, some drafts assume a > controlled environment where metric values are closer or equal to real > values where as other drafts assume a less or no access control and propose > abstracted metric values to reflect preferences w.r.t. these metrics. **** > > ** ** > > So it could be useful to include attributes in the metric definition > reflecting their degree (may be yes/no) of abstraction, > Let me try to understand. The hopcount metric might say 5 hops, and then a "hopcount-detail" will give the exact 5 hops; an AScount metric might say 5 ASes, and ASPath then lists the 5 AS's, and then routePath lists the spwcifi routes, for example? Or this is too detailed? > or whether their values are explicitly provided or are just used in a > hidden way to filter or tie-break other metric values. > Filtering-only metrics can be tricky, but of course interesting. > ** > > Besides, most currently documented ALTO metrics relate to the transport > topology where as the protocol architecture and initial extension > discussions mentioned metrics relating to capabilities, of endpoints such > as storage or CPU capacity. So I could be useful to document the potential > providers of the different metrics and the potential users. > I am not sure we may want to combine transport and storage/CPU metrics in a single documents. My first reaction is that separate documents may be a more modular design, and I can think more. Thanks! Richard > **** > > ** ** > > What is your opinion?**** > > ** ** > > Thanks**** > > Sabine**** > > ** ** > > ** ** > > ** ** > > ** ** > > *De :* [email protected] [mailto:[email protected]] *De la part de > * Y. Richard Yang > *Envoyé :* lundi 14 octobre 2013 01:20 > *À :* IETF ALTO > *Cc :* [email protected]; RANDRIAMASY, SABINE (SABINE); > [email protected]; Greg Bernstein; Qin Wu; Young Lee > *Objet :* ALTO Extension: Defining a Cost Metrics document?**** > > ** ** > > Dear all,**** > > ** ** > > I am reading up on the documents that define cost metrics. **** > > ** ** > > The motivation is that the base ALTO protocol ( > http://www.ietf.org/id/draft-ietf-alto-protocol-20.txt) has defined only > one Cost Metric: 'routingcost':**** > > ** ** > > - Defined the semantics at Sec. 6.1.1.1 of , and then listed it at Table 3. > **** > > ** ** > > - Used "hopcount" in examples of Sec. 9.2.3 and 9.2.4, but the semantics > of not formally defined.**** > > ** ** > > Given the aforementioned state of the base protocol, I see good value in > that the WG produces a WG document that defines a relatively complete set > of Cost Metrics.**** > > ** ** > > I particular, I read the following:**** > > ** ** > > - http://tools.ietf.org/html/draft-lee-alto-app-net-info-exchange-02**** > > (Sec. 3.4 introduced three metrics: hopcount, latency, pktcost, and cost) > **** > > ** ** > > - http://tools.ietf.org/html/draft-wu-alto-json-te-01**** > > Defined a set of metrics: in Sec. 4. This work, as stated in the > document, is motivated by **** > > ** ** > > - http://www.ietf.org/id/draft-ietf-ospf-te-metric-extensions-04.txt**** > > ** ** > > During the review of ALTO base protocol, we are suggested to document > performance metrics (cost metrics) per the guideline of **** > > - RFC 6390 Guidelines for Considering New Performance Metric Development. > A. Clark, B. Claise. October 2011. (Format: TXT=49930 bytes) (Also BCP0170) > (Status: BEST CURRENT PRACTICE)**** > > ** ** > > Here a first question, I have, is whether the authors will produce a > "simple" document, at the upcoming IETF, whose only purpose is to:**** > > ** ** > > define a set of cost metrics, including the nameing, the semantics, ... > following the guideline per RFC 6390, that can benefit the base protocol.* > *** > > ** ** > > I feel that such a document is focused, and has good value by itself.**** > > ** ** > > The implications of the introducing multiple cost metrics can be explored > in another document, which I will send in another email shortly.**** > > ** ** > > Thanks.**** > > ** ** > > Richard**** > > **** >
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