Date: Fri, 11 Nov 2016 09:49:30 +0800 From: Erich Dollansky <erichsfreebsdlist@alogt.com> To: "John W. Kitz" <John.Kitz@xs4all.nl> Cc: <freebsd-arm@freebsd.org> Subject: Re: How to change MAC address on RPI-B? Message-ID: <20161111094930.46f55a60@X220.alogt.com> In-Reply-To: <000c01d23b3a$c06e1ef0$414a5cd0$@Kitz@xs4all.nl> References: <005701d23a7d$71400630$53c01290$@Kitz@xs4all.nl> <20161110065105.77a19e3b@X220.alogt.com> <000c01d23b3a$c06e1ef0$414a5cd0$@Kitz@xs4all.nl>
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Hi John, On Thu, 10 Nov 2016 11:11:02 +0100 "John W. Kitz" <John.Kitz@xs4all.nl> wrote: > > To the best of my recollection at the time there was no need > > whatsoever to configure these NICs into promiscuous mode, which in > > you need this for fault-tolerant computing. A machine or a device > with a known goes down, the failure will be detected and another > device or machine is configured to take over the other's task by also > taking over the other's MAC address. The communication partners will > only a delay but not a failure. > > JKi: I'm curious, would, in your experience, the impact of any delay > incurred by tinkering with addresses at both layer-3 AND layer-2 in a > failover situation be less in comparison to any delay incurred when > tinkering with the addresses at layer-3 ONLY and leave the recovery of > addressing issues at layer-2 to the relevant protocols? > it depends of what you want. When the machine connecting to the fault-tolerant machine is not fault-tolerant, it will not be able to change any addresses. All it will do is repeating requests. A watch-dog should have realised by then that either the interface or the machine with the interface is down and should have activated either a different interface or a different machine. It is just one of many option you have. And it is a cheap option as you can make even FreeBSD fault-tolerant with this as the operating system does not play any part in this kind of fault-tolerance. Erich
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