> > This problem should not exist. Nagios --> Router A --> Router B uplink1+2 ring (and Router B is in a ring topology which closes in it)
http://tinypic.com/view.php?pic=11uhx7a&s=3 (this is the logical layout) Yes. But if you cut the 2 uplinks from Router B, then the Nagios machine will see Router B as up but will not be able to reach any other router from the ring and will thus alert that all other routers are down (which is not true). I mean having split the ring into the 2 halves you suggested that: C has parent B, D has parent C, E has parent D G has parent B, F has parent G => B up but B uplinks to C and G down -> alerts that C and G are down although they aren't Can this be eliminated ? (I'm sure the solution should be simple and obvious but I'm not being as careful as I should to see it) Am I right ? P.S. Currently I am monitoring each link state (up/down) by using SNMP interface queries (on Cisco routers) and the hosts themselves with ping/icmp on loopback interfaces that are propagated throughout the network for reachability(OSPF). > > Because if you cut the ring in 1 place all nodes can still be reached. > So no router will go down. If you cut it in 2 places you loose part of > the ring and only get alerts for the nodes directly on the other side of > the cuts from your perspective. > > If you alert on unreachable as well then you get all the alerts you > tried to get rid of by introducing the parent relation in the first > place. So don't use them. > > You need an additional means of detecting your first cut in the ring as > all routers can still be reached at that time and you will never know > you had a problem unless you alert on the actual link conditions. > ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Nagios-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null
