Hi Greg, The case with this draft is that IGP drafts [RFC7471] and [RFC7810] uses 24 bit integers for delay and delay variation already to flood this in TEDB. The PCEP [RFC5440] defined METRIC value as 32 bit IEEE floating point format. Changing that in this extension doesn’t seem wise.
It is important to note that this draft is not about measurements, but how to use delay/delay-variation as constraints/criteria and use the date in TEDB for calculating a suitable E2E path (and thus before the path is setup and data flowing). I personally don’t see the benefit in changing format now. Thanks! Dhruv From: Greg Mirsky [mailto:gregimir...@gmail.com] Sent: 15 September 2016 23:00 To: Dhruv Dhody <dhruv.dh...@huawei.com> Cc: Alia Atlas <akat...@gmail.com>; The IESG <i...@ietf.org>; pce@ietf.org; draft-ietf-pce-pcep-service-aw...@ietf.org; pce-cha...@ietf.org Subject: Re: [Pce] Alia Atlas' No Objection on draft-ietf-pce-pcep-service-aware-12: (with COMMENT) Dear All, delay and delay variation are usually calculated using timestamps collected at two endpoints of the path. AFAIK, there are two formats, NTP and IEEE-1558v1/v2, being used in OAM protocols to measure Latency/Jitter with different precision determined by length of fractional seconds field. Hence my question, wouldn't it be easier, more intuitive to use one of the formats or, even better, allow both with explicit indication of the format being used, e.g. as in RFC 6734. Regards, Greg On Thu, Sep 15, 2016 at 9:14 AM, Dhruv Dhody <dhruv.dh...@huawei.com<mailto:dhruv.dh...@huawei.com>> wrote: Hi Alia, Thanks for your comment, see inline... > -----Original Message----- > From: Pce [mailto:pce-boun...@ietf.org<mailto:pce-boun...@ietf.org>] On > Behalf Of Alia Atlas > Sent: 15 September 2016 19:13 > To: The IESG <i...@ietf.org<mailto:i...@ietf.org>> > Cc: pce@ietf.org<mailto:pce@ietf.org>; > draft-ietf-pce-pcep-service-aw...@ietf.org<mailto:draft-ietf-pce-pcep-service-aw...@ietf.org>; > pce-cha...@ietf.org<mailto:pce-cha...@ietf.org> > Subject: [Pce] Alia Atlas' No Objection on > draft-ietf-pce-pcep-service-aware-12: (with COMMENT) > > Alia Atlas has entered the following ballot position for > draft-ietf-pce-pcep-service-aware-12: No Objection > > When responding, please keep the subject line intact and reply to all email > addresses included in the To and CC lines. (Feel free to cut this introductory > paragraph, however.) > > > Please refer to > https://www.ietf.org/iesg/statement/discuss-criteria.html > for more information about IESG DISCUSS and COMMENT positions. > > > The document, along with other ballot positions, can be found here: > https://datatracker.ietf.org/doc/draft-ietf-pce-pcep-service-aware/ > > > > ---------------------------------------------------------------------- > COMMENT: > ---------------------------------------------------------------------- > > I am concerned that the 24 bit values of microseconds are being represented > in IEEE 32-bit floating point. > A quick look at conversions indicates that all integers will up to 6 > significant figures can be converted without loss of precision. That > implies that values of over 1 second may not be accurately sent. It would > be useful to at least refer to the precision issue in the document. I don't > expect that the loss of precision at the microsecond level is critical. > > [Dhruv] I could add a sentence for delay and delay variation - The conversion from 24 bit integer to 32 bit IEEE floating point could introduce some loss of precision. Will this be okay? Regards, Dhruv > _______________________________________________ > Pce mailing list > Pce@ietf.org<mailto:Pce@ietf.org> > https://www.ietf.org/mailman/listinfo/pce _______________________________________________ Pce mailing list Pce@ietf.org<mailto:Pce@ietf.org> https://www.ietf.org/mailman/listinfo/pce
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