Sure, STP is described at: http://en.wikipedia.org/wiki/Spanning_Tree_Protocol http://en.wikipedia.org/wiki/Spanning_Tree_Protocol When an 802.1D capable bridg

Sure, STP is described at: http://en.wikipedia.org/wiki/Spanning_Tree_Protocol http://en.wikipedia.org/wiki/Spanning_Tree_Protocol When an 802.1D capable bridge appears on a network with STP, the other bridges will all drop their forwarding table and learn again from scratch. Failure mode sounds spookily like the one described.