Date: Thu, 23 Jan 1997 20:04:09 +1030 (CST) From: Michael Smith <msmith@atrad.adelaide.edu.au> To: ccsanady@me.bla.com (Chris Csanady) Cc: jdp@polstra.com, freebsd-hackers@freebsd.org Subject: Re: Fault-tolerant network with 2 ethernets Message-ID: <199701230934.UAA21143@genesis.atrad.adelaide.edu.au> In-Reply-To: <199701230833.CAA28531@me.bla.com> from Chris Csanady at "Jan 23, 97 02:33:27 am"
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Chris Csanady stands accused of saying: > > > >A client wants a fault-tolerant LAN setup like this: > > > > ethernet A (100BaseT) > > ---+------+------+------+------+------+--- > > | | | | | | > > host host host host host host > > | | | | | | > > ---+------+------+------+------+------+--- > > ethernet B (100BaseT) > > > >The goal is that either ethernet could go down, yet all the hosts could > >still talk to each other. Or, one of the ethernet cards on a host could > >go down, and it could still talk to all the other hosts. In either > >case, it has to happen automatically, without manual intervention. Load > >balancing isn't a goal, just fault-tolerance. Speaking of sickness : - hack the kernel to support duplicate addresses on different interfaces (ie. emit packet on all interfaces with the desired source address) - hack the listening side at a low level (ether layer or so) to pick one interface to listen to a given host on. Devise a simple heuristic for deciding when to swap (maybe count incoming packets from each host & swap when the "off" host gets some number ahead). Either way, it's not something that's trivial to do, and has previously been observed, it's really concentrating on the wrong parts of the picture. -- ]] Mike Smith, Software Engineer msmith@gsoft.com.au [[ ]] Genesis Software genesis@gsoft.com.au [[ ]] High-speed data acquisition and (GSM mobile) 0411-222-496 [[ ]] realtime instrument control. (ph) +61-8-8267-3493 [[ ]] Unix hardware collector. "Where are your PEZ?" The Tick [[
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