In a communications network, a database is searched for a least cost route in response to a call request from a subscriber, and a connection is established along the least cost route between the calling subscriber and a called subscriber. For the duration of the call, the database is repeatedly searched...http://www.google.com/patents/US6023501?utm_source=gb-gplus-sharePatent US6023501 - Least cost routing with repeated searches for lower cost route
