Network switch issues

[Bryan]

I'm looking for some wisdom from our networking saavy boarders... After the storm on Friday night, our in-house network is schizo. Looks like our print server and a network hub got zapped. I think whatever took out those two also traveled back down the CAT5 and took out several ports on our main switch. Is it possible/common that only a few ports would get cooked while the rest of the switch is just fine? I always seemed to think that if the surge was enough to take out a port, it would take out the whole thing. Same thing with the hub. I reset it, everything powers on OK and I even get a good link, but for some reason it will not transfer traffic. Replaced it with a different switch and everything is fine.

I just always assumed that if something got zapped, it really got fried to the point of not being able to power on. Never experienced a situation where just the logic got cooked. I'm really baffled by this one.

[Docta]

yo b,

i know i have had switches in the past with bad ports, so i would assume it would be possible for just some to have been fried. if the surge traveled through the wire then i suppose there would be a possiblity of just the contacts on specific ports being hosed somehow. can you go in and look at the ports through the management interface?

i'd maybe call your vendor to see if they have ideas.

[Bryan]

It's an unmanaged switch so there's really no way to check on the status of the ports other than the status LEDs on the front. It looks like 5 ports got cooked on the big switch along with the uplink port on another hub and the LAN port on our print server. Looks like some stray voltage from a nearby lightning strike must have found its way onto the CAT5 and knocked out some ports. Weird... but it's the only thing I can think of.

[daemon]

I've seen individual ports "go bad", although not from lightning. a deja search confirms that this isn't all that uncommon, though.

APC actually makes a 1u network surge protection (http://www.apcc.com/resource/include/techspec_index.cfm?base_sku=PRM24&language=en&LOCAL.APCCountryCode=US) device. surprisingly it's not even that terribly expensive.

-brian

[daved]

May not be lightning per se, but static or differential charges propagated along the network grounds. Who knows?

In any event, ports go bad individually, ESPECIALLY from things like static or leaking current. In a well designed piece of equipment inputs and outputs are isolated from the active circuitry, if only to properly interface and match levels etc. The isolation is designed to keep something that fries a port from frying not only switch guts, but other connected gear. Switchmakers lawyers don't want any hint of liability for a lightning or static strike from a WAN connection taking out laser printers and unrelated computers. So, it's not uncommon for stuff to be isolated by transformers, active circuitry or even optical links that completely seperate the switching components from the interconnects.

-d-