A first router is configured for monitoring prescribed attributes of an active path connected to the first router, and supplying an update message to a second router, according to a prescribed routing protocol such as Enhanced Interior Gateway Routing Protocol (EIGRP), that specifies a detected change...http://www.google.com.hk/patents/US7720054?utm_source=gb-gplus-share專利 US7720054 - Router configured for outputting update messages specifying a detected attribute change of a connected active path according to a prescribed routing protocol
