Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!thunder.mcrcim.mcgill.edu!snorkelwacker.mit.edu!apple!usc!rutgers!aramis.rutgers.edu!athos.rutgers.edu!hedrick From: hedrick@athos.rutgers.edu (Charles Hedrick) Newsgroups: comp.dcom.lans Subject: Re: Ethernet "heartbeat" Message-ID: Date: 19 May 91 00:17:30 GMT References: <12164@uwm.edu> <1991May16.004523.21301@berlioz.nsc.com> <104479@sgi.sgi.com> <1991May16.134857.1@ptavv.llnl.gov> Organization: Rutgers Univ., New Brunswick, N.J. Lines: 14 >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. I'm not sure why you say this. Some older cisco routers use Interlan multibus Ethernet controllers. With those controllers, cisco checks heartbeat, and declares the interface down if it's missing. This seems to detect disconnected cables fine, except for a few cases where it's partly in and so not all signals are interrupted. (The test can be disabled by a configuration command.) Newer cisco products use a cisco controller card, which can hear its own transmissions. This allows a more complete test than what you get from heartbeat. But for the majority of controllers heartbeat is the best you can do, and does seem worth doing.