Charles Sprickman wrote: > > > Scott Granados wrote: > >> This problem sounds a lot like a dissimilar grounding issue. Sounds > >> like a potential between buildings is causing problems. I don?t > >> know if this is feasible but a common ground might solve some of the > >> problems. > >> > > Our electricians say that everything is correct, that all the > > grounding circuits are interconnected and they measure their > > parameters annually. I lack the necessary qualification to call them > > liars (even if they are lying which I doubt). > > It still might be interesting next time you have a failure to put a > voltmeter between the switch chassis ground and each pin on the > ethernet cable that blew the port. If you see anything measurable > that might at least tell you if its something like a transient > lightning-induced spike or a weird grounding issue (I think).
If there is something, it must be transient. I have had it measured and it's exactly zero. > > OT, but long ago I worked at an ISP where we once had a few hundred > phone lines going to modems and the lines ran up the buildings > freight elevator shaft. Each time someone had a freight elevator > delivery you could hear the sound of a bunch of modem relays > clicking as a bunch of users were disconnected. This was voltage > induced in the phone cables from whatever power cable the bundle was > lashed to. :-) Well we thought that Ethernet protective devices would mitigate such problems, and maybe they do mitigate them after all (i.e. I would get toasted switches every day and not twice a year). -- Victor Sudakov, VAS4-RIPE, VAS47-RIPN sip:[email protected] _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
