In our office, an engineer accidentally connected a LAN cable from CISCO Catalyst switches to Alcatel switches. Suddenly the whole end user network went offline. When the engineer unplugged the cable, network restored immediately.

Will there be any problem the next day? Will the configuration remain working?

  • It wont cause lasting damage if that is what you are asking.
    – soandos
    Jul 26, 2011 at 12:27
  • I see, so my actual question was the configuration will remain as working? Do configuration will be wipe off, suppose I heard the engineer said that part has dedicated ports?
    – thunber
    Jul 26, 2011 at 12:28
  • Can't why if its working one day, it will not work the next.
    – soandos
    Jul 26, 2011 at 12:28

1 Answer 1


It probably created a loop when they connected the second switch. This should not cause any lasting effects because, assuming we are referring to managed switches, their configuration is stored in memory.

You probably need to enable spanning tree on the second switch.

  • yes, but I'm not involve in any of these setup. As for the end user PC network will not be down after recovery from this incident right?
    – thunber
    Jul 26, 2011 at 12:46
  • 3
    No, everything should work as expected. If it's working now, it'll work tomorrow as well.
    – slhck
    Jul 26, 2011 at 12:48
  • Ok, that great to know!
    – thunber
    Jul 26, 2011 at 12:51

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