Multiple redundant paths between LAN segments can greatly improve fault
tolerance. But, unfortunately, multiple paths have a serious side effect:
frames can cycle and multiply within the interconnected LANs.
To prevent this, bridges communicate with each other in order to determine
a spanning tree. Data is sent along this spanning tree topology
-a subset of the original topology- that has no loops.
Once the bridges determine a spanning tree, they virtually disable appropriate
interfaces or a whole bridge in order to create the spanning tree out
of the real topology. If one of the links in the spanning tree fails,
the bridges run the spanning tree algorithm again and determine a new
The application guides you step by step through the spanning tree algorithm.