Hi Dhruv and all, I also agree with you that "Bandwidth is well suited to filtering to get endpoints that can provide the requested bandwidth". An ALTO Server may also use other TE metrics to filter on other abstracted metrics. This may be convenient for ALTO Servers that do not wish to unveil their TE metrics values to all Clients.
The ALTO Server may protect from "malicious" requests by setting thresholds on the granularity of the filtering interval, e.g. reject [a, b] with b-a < 10, and or reject series of requests with e.g. "< a" with "too close" values of a. Best regards Sabine -----Message d'origine----- De : Dhruv Dhody [mailto:[email protected]] Envoyé : mardi 22 juillet 2014 17:23 À : Qin Wu Cc : [email protected]; Y. Richard Yang; RANDRIAMASY, SABINE (SABINE) Objet : Re: statistics operators for ALTO cost metrics Hi Qin, One point to note that would be that metrics in IGP drafts are in terms of a TE link, in ALTO we need to worry about E2E cost ( or cost of an abstract link incase when ALTO also convey an abstract topology), so these cost metrics are composite metrics. ALTO server may rely on database populated by routing protocols, or a PCE, or a measurement system. Thus ALTO server rely completely on the source on how this cost metric is derived and all it can do is to specify the source (or composition mechanism) in its reply. Bandwidth is a bit different from the delay, jitter and loss which can be easily composed to an end to end metric. Bandwidth is well suited to filtering to get endpoints that can provide the requested bandwidth. As a cost it might either represent the bottleneck link for the E2E path. Question for us to consider is - do we need all of max bandwidth, max resv bandwidth, available bandwidth etc; and what format they should be in. Dhruv On Fri, Jul 18, 2014 at 8:13 AM, Qin Wu <[email protected]> wrote: > Hi, > > Motivated by RFC3630 and draft-ietf-isis-te-metric-extensions, we > define 11 alto cost metrics, > > The value of these alto cost metrics are high aggregated value, we may > have several statistics operators, e.g., > > Mean, variance, avg, percentile). > > In the current draft, delay and delay jitter are both on delay, we use > mean > > For delay and use variance for delayjitter. > > It is not clear these statistics operator are appropriate for them? > E.g., should we use percentile for bandwidth related cost metric? > > Any opinion? > > > > Regards! > > -Qin _______________________________________________ alto mailing list [email protected] https://www.ietf.org/mailman/listinfo/alto
