In practice, switching is a continuously changing mixture of point-to-point connections, point-to-multipoint connections with low fanout, and point-to-multipoint connections with high fanout. The switching elements of a switch optimized for point-to-point connections are additionally enabled to copy...http://www.google.com/patents/US5202885?utm_source=gb-gplus-sharePatent US5202885 - ATM exchange with copying capability
