> -----Original Message----- > From: Robert Carter [mailto:robert.car...@octoscope.com] > Sent: Friday, March 15, 2019 6:03 AM > To: Keller, Jacob E <jacob.e.kel...@intel.com>; > linuxptp-devel@lists.sourceforge.net > Subject: Re: [Linuxptp-devel] mcast_bind patch > > > Can you justify why we should *always* want this? perhaps there's > > reason to want a different subnet. > > This patch was the minimal, localized change required to address a > problem we were seeing in our PTP application. Where an interface had > multiple IP addresses, this change made source address selection > deterministic, rather than random. Random didn't work. >
Ok, it makes sense to be deterministic here, instead of random. > > We already force the specific interface via its index, so this only > > helps in the case where there are multiple subnets on the same > > interface.. > > Correct. Multiple IP subnets on a single physical interface isn't an > unusual networking configuration. Right. > > > Would it make better sense to allow a configuration option to specify > > which subet? > > Maybe. Maybe not. We needed ptp4l to be consistent. Adding a > configuration item would have taken considerably more time and effort to > implement. Adding a configuration option is design consideration. The > patch I've provided is one possible solution to the problem we encountered. > Sure. I'm just trying to understand the problem, and make sure that the specific implementation solves the right problem. It sounds like the problem isn't "it picked the subnet I didn't want" but rather "different instances of ptp4l didn't consistently pick the same subnet, but I don't really care which one they pick as long as it's stable"? If it's the former, I'd rather see some sort of option that lets you specify the subnet. However, being deterministic is reasonably useful. Is my description of the second option accurate? Can you describe the symptoms that happen when the wrong subnet is chosen? Thanks, Jake > Best regards, > > Bob Carter _______________________________________________ Linuxptp-devel mailing list Linuxptp-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-devel
