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RE: Strange port loss [7:84887] posted 02/25/2004
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were any cables plugged into the ports in question?

> I'm going to make a guess that in each case the four ports share a common
> chip in the hub/switch. If that is true, then if something fries one port
> takes out four. I don't believe that Cat5 has the same issues with
> electrical ground loops that coax has. Therefore I'm not too concerned
> the power to the PCs. This sounds like a layer one issue. So, I'd trace all
> four of the wires from switch to PC looking for frayed insulation and any
> possible source of electricity that might touch it. I'm thinking modular
> workspaces with wires running through channels in the components. I'm also
> thinking about wet floors and maybe in-floor electrical receptacles. The
> patch cord from the PC to its local network jack seems to always receive
> most abuse.
> Fridays seem to be a bad day. Do cleaning crews do anything special on
> certain days? Can you think of anything in the office that changed about
> time that the trouble started? Move of office components? New janitor? New

> large electrical feeds run adjacent to wiring?
> When you find the solution - this may be one for the ComputerWorld Daily
> Shark.
> -----Original Message-----
> From: Steve Smith [mailto:ssmith@xxxxxxxxxxx] 
> Sent: Wednesday, February 25, 2004 9:06 AM
> To: cisco@xxxxxxxxxxxxxx
> Subject: Strange port loss [7:84887]
> Hey gang has anyone seen this. I have a client who had a hub that "just
> quit working". They put in an old Boca hub and everything ran fine until
> the following Friday. Then 4 of the ports just locked up and went amber.
> Even if you unplugged the hub and plugged it back up it would not work
> on those ports. I went out and put in a Cisco Fast400 hub while while
> waiting for there switch to come in. The following Friday the Cisco hub
> lost 4 ports. 3 where amber and one was locked green. The hub will not
> do anything now but light up those ports. I replaced the hub with a Cat
> 2948 switch last Thursday. Monday they lost 4 ports again! They moved

> those 4 connections to different ports and they where able to continue
> working. On the switch, even after reboot, the 4 ports just flash amber
> and the switch shows them as faulty.
> Does any have any idea what could be causing this to happen. The switch
> is plugged into a UPS.
> thanks,
> Steve Smith
> Enterprise Engineer
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