Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!elroy.jpl.nasa.gov!decwrl!sgi!vjs@rhyolite.wpd.sgi.com From: vjs@rhyolite.wpd.sgi.com (Vernon Schryver) Newsgroups: comp.dcom.lans Subject: Re: Ethernet "heartbeat" Message-ID: <105002@sgi.sgi.com> Date: 19 May 91 03:20:33 GMT References: <12164@uwm.edu> <1991May16.004523.21301@berlioz.nsc.com> Sender: guest@sgi.sgi.com Organization: Silicon Graphics, Inc., Mountain View, CA Lines: 30 >>SQE is unlikely to be very helpful in finding loose connectors, but I do have >>some workstations that gernerate LOTS of errors if they don't se it. If they >>run NFS the error reporting can essentially kill the system. > Some older cisco routers use Interlan > multibus Ethernet controllers. With those controllers, cisco checks > heartbeat, and declares the interface down if it's missing. Ok, it seems an unnamed workstations (which brand and models?), some older Cisco routers (what about newer ones?), and VMS-VAXen pay attention to heartbeat. Are there any others? Can and are any or all three of these commonly configured to ignore the absense of heartbeat? Consider that Cisco routers tend to be far less common than workstations, and are less likely to have loose or disconnected cables (tho with unhappier consequences). VAXen are not the most popular machine this decade. If these are the only machines that care, it seems to me that heartbeat (or SQE which is not identical, but close enough) is almost useless in real life. I care, because I'm wondering if a bunch of BSD-style ethernet drivers I know about should be changed to notice missing hearbeats. They did notice about 3 years ago, but only by mistake. If they should care, where should they report the problem? Would a printf be appreciated or cursed? Say one printf on the first missing heartbeat? My guess is it would be cursed, because almost all transceivers have heartbeat turned off. Vernon Schryver, vjs@sgi.com