On 19 Feb 2014, at 09:50, Richard Cochran <richardcoch...@gmail.com> wrote: > On Tue, Feb 18, 2014 at 07:08:41PM +0100, Delio Brignoli wrote: >> >> I also assumed the peer delay had to be non-negative to be meaningful. >> Would you be OK with a patch that introduced a minimum acceptable peer >> delay configuration option? > > I think even for gPTP, the measured mean peer propagation can > legitimately be less than zero. Let me explain. First, consider the > performance limits from the 802.1AS-2011 standard.
[…] I looked at the standard after your first reply and understood your point. That’s why I was asking if you’d be OK with a configuration option to set the minimum acceptable peer delay. > I think we have to allow this, or maybe rethink our peer delay > measurement for gPTP. In any case this patch is not correct, since it > will prevent the port from being labeled as asCapable, and it also > prevents discovering the neighborRateRatio. > > It is perfectly fine for the measured propagation to be negative as > long as the calculation for the master offsets are correct after > applying the neighborRateRatio. Preventing the port from being labelled asCapable and avoid calculating neighborRateRatio is exactly what I want to do. I am working with specs layered on top of 802.1AS-2011 which require me to flag a port as non-asCapable if the peer delay is negative. Thanks — Delio ------------------------------------------------------------------------------ Managing the Performance of Cloud-Based Applications Take advantage of what the Cloud has to offer - Avoid Common Pitfalls. Read the Whitepaper. http://pubads.g.doubleclick.net/gampad/clk?id=121054471&iu=/4140/ostg.clktrk _______________________________________________ Linuxptp-devel mailing list Linuxptp-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-devel
