Normal 802.3 Ethernet requires a tree topology. If a ring or a loop exists, then packets will be forwarded around the ring indefinitely. If the ring is broken, then there is no possibility of packets being propagated forever. This invention shows how to quickly impose a virtual break in the ring such...http://www.google.com/patents/US7355965?utm_source=gb-gplus-sharePatent US7355965 - Apparatus and method for rapid detection of unidirectional breaks in a network ring
