2960s-24ts-s problem

[sharbaugh]

Installed a new 2960s-24ts-s in our network of 7 other Cisco switches.  It had been configured and tested on my bench for about a month.  When it was connected to our network (only cross-over, no computers connected to it), somehow it caused a spanning-tree fault on two other switches, killing our users database connections.  All had to reconnect via there apps, it did not reconnect.  What would cause this reaction on other switches just by powering up an new switch? And, how can we avoid this in the future?

[Leo Laohoo]

Installed a new 2960s-24ts-s in our network of 7 other Cisco switches.

You mean you stacked 7 2960S together?

[sharbaugh]

No.  All switches are connected in star topology.  This switch, along with another one, is actually in another building.  Cat 6 runs underground to other building.  No, it does not exceed 328'.  All we did was move the 2960 to the other building, boot it up, and then patched it to another switch in this building.  (We have two Cat6's underground and one was unused).  So, 2960 connected, fairly long run, to a 520G.  We had errors on 6 or 7 ports on the 520g and also 5 or 6 ports on another 2960 connected to the 520g also.  Connection was lost only for a second or two but long enough to kill database connections.  What caused the "blip"?